Jim's Cushman Scooter Site

Vanguard Conversion Information

One of the subjects that I get tons of email about is how to install a Vanguard Engine in a Cushman Eagle. This page is a condensation of my email correspondence for the past few months on this subject. I welcome comments and your suggestions for additional information.

What is in a "Vanguard Kit"
Where can I buy a Vanguard Engine
What should I know before I buy?
What kind of air cleaner do I need?
What about fuel pumps?
What is the little valve on the carb?
Can I relocate the fuel pump?
Do I need an in-line gas filter?
What is "red Llne" on a Vanguard?
Are all the bolts Metric?
How is the carb connected to the throttle?
How do I make a bell crank?
What kind of Ignition Switch can I use?
What kind of battery do I need?
Do I need a starter interlock?
Can I use the raised type floor pan?
Is the present chain strong enough?


What is a Comet Transmission?
How is the Comet held on the engine?
Can I just use the original transmission?
How do I choose a sprocket ratio?
Are larger tires required?
Are disc brakes necessary?
Are there special mods for disc brakes?
OK, I am ready, How do I start?
How can I check my charging system?
How do I adjust the Comet drive belt?
My comet 40 System Jerks!
Where can I get loom for harnesses?
I dropped a bolt in my engine!
How do I get the flywheel off?
How can I advance the timing?
Optional Items you might want
Where can I get more Vanguard Info?

What is in a "Vanguard Kit"?
A vanguard “kit” consists of an air cleaner, exhaust system with clamps, throttle reversing bell crank, jackshaft with braces, engine to frame brackets, a Comet driver and driven pulleys, a Kevlar drive belt for the Comet, a battery box, and a clutch cover.  You will also need to modify your existing throttle cam system or purchase a “jackhammer” type motorcycle throttle.  You can also buy a new reproduction Cushman Eagle frame if you don't have one. 

Where Can I get a Vanguard engine?
I am sure you can order one from your local Briggs & Stratton dealer, but it might be pretty pricey. Most of us using engines that are  “surplus”, but still unused in the original shipping box. 

What should I know before I order a Vanguard Engine?
First choose your horsepower. I suggest the 16 or 18 HP, preferably the 18 HP. The 18 HP will run about 68 to 70 MPH and will have very good acceleration. The 23 HP has so much acceleration that it is scary. Above 18 HP a different air cleaner is required. Be sure the engine comes with a starter, a starter solenoid, an oil filter assembly and either the 10 or 15 ampere charging system with the electronic regulator module. Most come with either the 10 or 15 ampere fully regulated charging system but some have only an unregulated DC output and are unsuitable for scooter use. Some have a rope starter, others only a cover over the air intake area. The rope starter is not necessary, but pretty handy if your battery runs down. Vanguard engines are made for many different brands of lawn equipment and the engine shafts vary.  The standard Comet systems require a 1-inch non-tapered shaft with a ¼ inch keyway.  There are at least two different tapered shafts. I believe there may now be a Comet available for one of the two tapers.

What kind of Air Cleaner do I need?
You can use the air cleaner that comes in one of the kits, or with a little ingenuity you can fabricate your own filter.  The original Briggs air cleaner has a rubber raceway between the engine shroud and the input of the air cleaner. This serves to pressurize the carburetor slightly. I do not know if this actually results in an increase in performance, but I have to assume that it does since Briggs went to the trouble of designing it..  If you make a flat low profile “pancake” air filter like the one pictured on my 1964 Silver Eagle Vanguard you can use the original rubber raceway and pressurize your air filter like Briggs does.  If not, a rubber plug is available from Briggs & Stratton to fill the hole in the shroud. It is part number 692082 and the description is "Plug-Blower Housing2.

What about the Fuel Pump?
If you are installing a Vanguard engine in an Eagle it will gravity feed and you do not need a fuel pump.  A fuel pump is required if you are installing the engine in a Step-Thru or similar scooter where the fuel must be pumped up to a higher level. The fuel pump is very reliable and will cause no trouble, so you can use a pump engine with an Eagle just fine.  The carburetors used with fuel pumps are very different than the carburetors used without fuel pumps. The needle and seat is completely different, one is designed for the higher pressure from the fuel pump and the other is designed for gravity feed with little pressure. You must be sure that no one has removed a fuel pump from the engine you buy. There is a dot code on every carburetor that indicates if it is a pump or non-pump model and this information is available in the B& S repair manual. Briggs engineers told me that it seem may run OK with the wrong combination, but it could cause rough running, stalling and other problems.

What is the little “valve” on the front of the Carburetor with a wire on it?
Some carburetors come with an Anti-Afterfire Valve. If you find a loose white wire that exits the shroud you may have one on your engine. It is an electric solenoid that screws into the front of the carburetor.  It is activated electrically by the ignition switch and allows fuel to flow. When the switch is turned off the fuel supply is shut off. It is of no value on a scooter, just something to break.  It is best to either remove the internal spring and plunger to disable it1 or remove and replace it with a Briggs & Stratton plug, part number 807723.  The B&S Description is “Plug-Carburetor (jet)” and part number is 690744 “Washer-Sealing” is included at a cost of $2.252

Can I relocate the fuel pump?
The fuel pump can be relocated anywhere you like. Any reasonable length of suction tubing back to the valve cover is fine. I put mine down in the "V" in the engine to the left of the carburetor. I made a .060 thick aluminum bracket and fastened it to the existing screws on each cylinder. It is just wide enough to fit the pump. It has some pretty fancy angles bent in it to get it to slip down in place so the existing screws can be used to fasten it.

Do I need an in-line gas filter?
I would strongly suggest using a good in-line filter. The screen in the Cushman tank filter may let some smaller particles through; the in-line filter is good insurance.

What is “Red Line” on a Vanguard?
3600 RPM is the maximum according to Briggs & Stratton. A fairly knowledgeable Dealer says you can get by with an occasional excursion up to near 4000, after which the valves float and bad things happen.   The horsepower and the maximum rated RPM of the engine can be greatly increased by replacement of stock parts with performance versions designed for go-cart racing. This is best left to the experts. 

Are all the bolts and tapped holes on a Vanguard Metric?
The bolts are all metric, as are most tapped holes in the block. The tapped holes designed to be used by the end-user are SAE fine thread. You will have to determine the thread of any hole you plan to use.

How is the carburetor connected to the throttle on the handlebar?
The original Cushman design twist-cam can be used if the cam and the two cross posts in the handle bar part are bright and clean and well lubricated. If they are rusted or rough it is going to be very hard to open up the throttle. Unless you are doing a Silver Eagle you will need to purchase a reverse twist throttle cam to make the speed increase when the throttle is turned counter-clockwise. You can also use a “jackhammer” type motorcycle throttle assembly, Carpenter part number. H-876031-3. It comes complete with a matching grip for the other side of the handlebar.  You will need a special cable to use with it. Carpenter does not list it, but some of the dealers have it. In particular, Bert Barnett has them, as does Arcadia Cushman and Jason Glass.  Just tell them it is for the Jack Hammer grip set.  It has a special little molded block for the grip end and you don't care what is on the other end because you will be trimming the cable to length to go to your bell crank. You also will have to make or buy a bell crank to reverse the direction of the carburetor. This is true whether you use the original throttle cam or use motorcycle type throttle.  The Briggs Vanguard carburetor pushes to increase speed, and this must be reversed to pull to increase speed.  It is not difficult to construct a little bell crank. You can also purchase one in your kit.

How do I make a Bell Crank?
Below is a close-up picture of the bell crank assembly. They can be made in various ways, and this is just a suggestion. The support bracket is made from a piece of 1 inch by 2-inch aluminum angle and the 1-inch side is notched as shown in the picture to clear obstacles. The 2-inch width side is trimmed shorter as shown.  It bolts to two existing holes in the engine. The bolt at the front requires a spacer to line the plate up correctly.  These holes are tapped for Metric thread screws.  The bell crank is made from 1/4-inch thick aluminum and has two miniature-flanged ball bearings in it, one pressed in from each side. A screw goes through the center of the two bearings from the top. Under the bell crank is a small washer that contacts only the inner bearing race followed by two thin nuts locked together. Then the balance of the screw goes through the support plate and has a flat washer, a lock washer and a nut on the underneath. The push/pull rod from the carburetor can be a piece of the original wire or a piece of 1/16inch brass welding rod. Note that it comes over and makes a very sharp right angle and comes up through a hole in the bell crank. It cannot slip out because it is captivated between the bell crank and the support plate under it. The two extra holes were for a possible change in ratio. You can see a small spring just under the choke lever that aids in pulling the carburetor back fully to idle. It is connected to the throttle cam on the carburetor along with the pull/push wire. The throttle cable is secured to the top of a 7/8-inch post threaded all the way through. The clamp is secured to the top of the post with a 6/32 machine screw and a clamp. I have been unable to find a part number for this clamp. It has a tang on it and there is a matching recess on the post to keep it from rotating. You can get by without the recess if you hold the clamp to keep it from twisting while tightening it.  The post is required to make the vertical alignment correct for the cable.  A second 6-32 machine screw and a lock washer secures the post from the bottom of the plate.  I used Locktite on everything to be sure nothing will ever comes loose.  If you want to do it the easy way Elbert Faris makes a bell crank for about $60.00 and you can see a picture of it at his Personal Page. Use the search page and type in Elbert Faris to see his ads.

What kind of Ignition switch can I use?
I prefer a standard electric start Silver Eagle switch to the cheap switch that Briggs supplies. The only difference is that with the original switch the charging lead from the electronic regulator is grounded when the switch is off. We can simulate exactly the same thing by connecting the lead from the electronic regulator directly to the accessory post of the switch. Since the lights will also be connected to the accessory terminal the regulator will see ground through the lamps when the switch is turned off.

What kind of Battery do I need?
The Vanguard is pretty easy to start. If you have a large battery box you can opt for a 14 ampere hour, although a 10 or 12 ampere hour battery is adequate if its rated CCA (cold cranking amperes) is about 160 or more.  Try to get one in the better batteries, not one of the cheap ones.  The better ones usually have YB in the part number. There is now a third choice, a battery that you fill once and seal permanently.  It cannot leak and does not require a drip tube like the  other models. Additionally, it has the greatest CCA of any of the models. This model will not fit in Elbert Faris’ battery box.

Do I need a starter interlock?
In a nutshell, yes.  If you ever start the Vanguard with the throttle advanced it will be gone in a flash before you could possibly react. A starter interlock requires that your foot be solidly on the brake before the engine can start.  Don’t try to get by without one.

Can I use the raised type floor pan?
Yes, you can use the raised floor pan by positioning the engine very close to it. You may want to put a 1-inch hole in the rear lip of the floor pan so that the oil drain plug can stick through and allow the engine to go forward the maximum amount. There are two oil drain holes on the Vanguard, front and rear so you don’t have to be concerned about every removing the plug from the front hole. You can also remove the oil plug and saw it off so it will be flush with the engine when reinstalled. Cut a standard screwdriver across the plug, wrap it with Teflon tape and screw it back in3

Is the present chain strong enough?
A few Guys have gone to larger chains, but it is not necessary. The #40 chain chain that Cushman used works fine with a Vanguard. The allowable load on a chain is determined more from the required service life than the load factor. It might wear out a tad faster with a Vanguard engine, but I don't think there is any worry about breaking it.  Just keep it adjusted properly and well lubricated. If you are using a performance high HP engine you might want to consider using premium #40 chain4. It has O Rings and heavier side plates and is much stronger than standard #40 chain.

What is a Comet Transmission?
The Comet Transmission system consists of two pulleys, a driver and a driven. The driver pulley has internal cams that operate with centrifugal force to squeeze the tapered sides of the pulley together and grip the belt. At idle the belt is extremely loose and cannot propel the scooter. As the RPM’s increases the sides of the driver pulley move closer together and the belt is forced into an increasing radius. At an idle the driver pulley at very small radius and the driven pulley at it’s maximum radius giving an initial reduction ratio of about 2.4:1, which is equal to low gear on a conventional transmission.  As the RPM’s continue to increase the centrifugal force on the driver pulley cams squeeze the sides of the driver pulley together and cause an ever-increasing belt radius. To provide enough slack to allow the larger radius and maintain the proper belt tension the driven pulley twists on a spring and expands, or widens and reduces its effective radius. At very high speeds the belt radius on both the driver and driven pulleys will be the same, or unity.  Since the Comet system assumes a ratio of unity at high speed, all the reduction from engine to rear wheel is accomplished by the ratio of the drive-out sprocket to the rear sprocket. A very important point is that the system is “load sensing”. That is, with a heavier load (a passenger on the buddy seat perhaps) the system will stay in “low gear” longer.  It is almost like having a computerized transmission, very smooth and automatic. Another way you can observe the load sensing capability is to rapidly accelerate to 50 MPH. When your reach that speed your tachometer will be indicating about 3200 RPM.  Now ease back and maintain a steady 50 MPH.  You will find that the RPM's will drop back to about 2800 with the lighter loading presented by the constant 50 MPH.  There is a chart of the Comet’s ratios under acceleration versus RPM at my Comet Ratio page.

How is the Comet clutch held on the engine shaft?
The shaft has a 3/8 SAE fine thread hole tapped in the end of it. The shaft is not long enough to come all the way to the outside of the Comet. Some folks just put a thick flat washer against the Comet and use along bolt to pull it down tight.  I prefer to machine a slug with a flange that serves as the washer, and then make the slug part about .010 inch shorter than the distance to the shaft. Then when it is pulled up with the bolt it bottoms against the engine shaft. If you do this you have to put a small amount of ¼ inch keyway on your slug because it will extend just into the keyway area on the Comet. This also prevents the slug from trying to rotate. The key is an integral part of the Comet; it does not use a separate loose key. You will also need a spacer behind the Comet to keep it from rubbing against the engine. This spacer should be tapered on the engine side to approximately match the taper on the engine shaft. 

Why can’t I use the original transmission instead of a Comet?
You can. But if you use the original transmission you will have a small v-belt rated for an absolute maximum of 8 HP running with 16 HP or more on it. Keeping the belt from slipping depends upon keeping it very tight and possibly treating it with one of the anti-slip compounds.  Some of the Guys I have talked to about their Vanguards with transmissions have said they have to accelerate very carefully to avoid burning the belt, other say no problem at all.  If you are just macho and like to shift that is OK I guess. But, with two bikes side by side, one with a Comet and one with a Transmission, the Comet will leave the transmission bike in the dust. Two reasons: One is the time lost to shifting - and this is important if you are in fast city traffic trying to keep out of harms way. The second reason is that when you throw full throttle to a Comet system the engine RPM immediately rises to about 2800-3000 RPM, very near the center of its maximum torque band. If you continue to hold full throttle it will not move much from around 2800-3000 RPM until you pass around 45-50 mph when it slowly starts increasing to the maximum rated RPM of 3600 at close to 70 mph.  If, while accelerating, you ease off the throttle the Comet will sense the reduced load and lower the engine RPM.  In other words, the harder the Comet is working the longer it stays in "low gear” It is sort of like magic! With a transmission the engine is out of its maximum torque band much of time, especially just after shifting into high gear.

How do I choose my sprocket ratios?
With the 18 HP Vanguard I use a ratio of about 2.6:1. You do want to be sure you choose your ratio so that you are not over-revving the engine. Likewise, you do not want to lug the engine either. I think ideally the gearing should be set so that the maximum attainable road speed occurs at the Briggs red line of 3600 RPM.  If you have a 16 hp engine this will occur with an overall ratio of about 2.7:1 and with a 18 hp about 2.6:1. The maximum speed will be very near 70 on flat terrain with no ambient wind. This results in a 2800 to 3000 RPM cruising speed in the 50's and about 3200RPM at 60MPH. Since the ratio of the Comet at high speed is unity, just divide the number of teeth in your large rear sprocket by 2.6 to find the drive-out teeth. For instance, a 60 rear requires a 23 drive-out.  As stated above, the Comet system is almost human in the way it determines its ratio at any point in time. With a slightly lower ratio between the sprockets it will just tend to stay in a higher ratio (low gear) a little longer to compensate, and it tends to mask out any small differences in the rear sprocket ratios. There is more general information on choosing the proper ratio at my sprocket ratio page.

 Some have asked why not lower the rear end ratio more and make it go faster. Well, the reason is that as you go increasingly faster the wind and rolling resistance increases very fast, almost logarithmically. For any given net Horsepower there is a maximum speed that can be attained, regardless of gearing. If you use a rear-end ratio that is too low the engine will not be able to pull the load and your top speed will be less than with the correct ratio. Conversely, if the ratio is too high the engine may rev in excess of its rated limits. As for acceleration, as explained above the Comet has the unique ability to sense load, and when it sees a large load like when you cram the throttle wide open from a standing start just it just stays in a low ratio longer.  The result is that the difference in acceleration you would expect to see, say between a 23 tooth and a 21 tooth drive-out sprocket to a 60 tooth rear sprocket, is not there because the Comet just stays in low ratio a little longer with the larger drive-out sprocket All rear end ratios quoted in this article assume a 52.5 to 53.0 inch tire circumference. If larger tires are used the ratio must be increased proportionately.  Just divide your tire circumference by 52.5 and raise the ratio by that amount. As an example, assume that you have 56-inch circumference tires and that you want to use my recommended (2.6 ratio for 52.5 inch tires).  Divide 56 by 52.5 to get 1.0667.  Then multiply 1.0667 times the original 2.6 ratio to obtain 2.773, which is the equivalent ratio for 56 inch tires. Note that you may have to compromise a little because the ratio you want may fall between two teeth.

Are larger tires required?
Standard Cushman tires and rims can be used.  However, you may prefer to use more modern high speed rated 10-inch tires for safety. Several of our vintage Cushman dealers carry 10 inch rims and tires. I suggest staying in the middle profiles, say 4.00 x 10. The 3.5 x 10  tires look wimpy and I don't like them at all. The very large 10-inch tires look too massive for a Cushman in my opinion.  Some tires carry special numbering systems so you will have to determine their profile. The mid size 10 inch tires are not much larger in circumference than the original Cushman tires. The rims are larger, but the tire profile is less for little net increase.  Some have used 12-inch rims and tires, but I suggest you stay out of this area unless you are an expert. Some frame and/or fork modifications may be required for 12-inch tires.

If you use the moderate sizes of 10-inch tires your stock speedometer gearing still be very close. This is because original Cushman speedometer gearing was designed to be correct for a tire a little larger than the Cushman 100 or Cushman 200. 

Are disc brakes necessary?
Disc brakes are very nice. If your budget allows only one disc brake I would opt for the front one. It is much better than the original front brake, has lots of stopping power, and it is very easy to install. The original Cushman rear brake with good linings and shoes is usually pretty effective, especially the later model with the lining on the shoes.

Are there any special modifications for a Disc Rear Brake?
Installing the front disc brake is a fifteen-minute job with no modifications of any kind. The rotor and actuator are mounted on a common support at the factory and no alignment of any kind is required. On the rear disc brake the rotor is on the axle assembly and the actuator is bolted to the frame of the scooter. You must align the actuator squarely on the frame, both laterally and squarly with the rotor. Most frames are not very straight in this area, and some shimming may be required.  If the wheel is shifted to tighten the chain you should re-check the alignment of the actuator in relation to the rotor. You will also have to make custom rear fender braces. The left side brace has to come out and over the brake caliper and then back in to the frame. I find that the fender is very solid with only the vertical brace, provided the front of the fender is fastened securely to the jackshaft cross brace with a triangular steel plate like Cushman did on some models.

OK, I have all my parts. How do I get started?
Start by rough-assembling the entire scooter, including the front fork and both the front and rear tires. You must first align the rear tire in the frame to track correctly behind the front tire. To accomplish this have someone else holds the front tire straight and use a long straight edge or stretch a string across the side of both tires. Have the other person turn the fork slightly until his string or straight edge falls equally on the front and back part of the front tire. Then shift the rear tire alignment in the frame until the string or straight edge falls equally across both the front and back part of the rear tire. Once this is done lock down the rear tire in this position. The axle will not usually be symmetrical in the adjustment slots because very few frames are true.  It will help to measure the difference from the rear of the slot (or other reference point) to the axle for future reference.  Leave the axle locked in this position until all layout work has been accomplished. The rear sprocket is now the reference point that will be used to correctly align the jackshaft. This will be accomplished later by placing a straight edge across the drive-out sprocket and the large rear sprocket. When aligning the jackshaft and drive-out sprocket both lateral and parallel alignment must be obtained. That is, the straight edge must fall across both sprockets and mate at on the entire surfaces across both sprockets. Spacers behind the drive-out sprocket may be necessary to obtain lateral alignment. Once the jackshaft has been installed and aligned correctly with the rear sprocket it then becomes the reference point for subsequent rear wheel alignment when adjusting the amount of slack in the chain.

If you purchase Elbert Feris’ kit he will send you a sheet metal template to use mark the engine and jackshaft holes. However, I find that not all frames are quite the same and if you drill first and find that it is a little off it is VERY hard to correct. Place the engine in its approximate location, as far forward as practical, or if you have a template you can use it as a guide for the correct forward-backward location. Bolt the two mufflers (assuming you have dual mufflers) to the engine and fashion temporarily supports at the rear of the bike to hold them in correct alignment both horizontally and vertically. Then shift the engine laterally as necessary until the two mufflers pass by the frame symmetrically. You must be sure that the engine is aligned square so that its shaft is perpendicular to the line of the frame.  The jackshaft pulley cam be adjusted laterally if necessary with spacers to mate correctly with the engine pulley, so don’t worry about it at this time.

Once the correct engine location is determined you can use a short transfer punch or a short pencil to mark the holes the cross brace. It is easier if you line the cross-brace with masking tape before you start so you can see your marks better.  If you have a sheet metal template it can be aligned with the engine hole marks and used to as a guide to mark the jackshaft holes. If you use a pencil wrap it with masking tape to press-fit in the engine holes to improve the accuracy of the mark.

How can I check my charging system?
At a fast idle - perhaps 2200 rpm or so – the 10 or 15 ampere system should charge up to about 13.8 volts to 14.4 volts, even with your lights on.  A partially discharged battery may take a long time to attain this voltage. You can tape a digital voltmeter to the handlebar and ride at least 40 mph for a several miles, or until the voltmeter stops increasing.  It should be at least 13.8 volts. You can also use a suitable ammeter to determine what the charging current it. However, unless you are very familiar with battery charging systems the voltmeter test will the most practical. Some of the reasons for a lack of charge are a bad electronic regulator, a bad stator coil, or a bolt that has dropped down the “V” of the engine and shorted out the stator winding. The part number marked on the electronic regulator is 394890 but Briggs says to use a 691185.

How do I adjust the Comet drive belt?
The center-to-center spacing between the engine shaft and the jackshaft (i.e. spacing between the dead centers of the two bolt holes that will secure the two Comet pulleys) must be exact for a particular belt. The jackshaft will extend out farther than the Vanguard shaft so here is the most accurate way to measure the spacing:  Put an accurate ruler against the back side of the Vanguard engine shaft and let it extend straight past the end of the jackshaft shaft.  Then eyeball as accurately as possible to the exact center of the jackshaft and take the measurement.  The Vanguard shaft is 1 inch in diameter, so add 1/2 inch to the measurement to get the true distance between the centers of the two shafts.  It is hard to design and built a system and have the spacing come out exact, so some means of minor adjustment is helpful.  Once this spacing is attained no further adjustment is ever made.  The belt will appear extremely loose, but it will tightens up as the driver pulley increases RPM.

My Vanguard 40-D system jerks!
First, be sure your spacing is correct, that the lateral alignment is correct with the required 3/8 inch offset (see the Comet instruction sheet) and that the belt and pulleys are clean. If that does not fix it, you have a lack of lubrication problem. Comet sells a special dry material in a spray can that looks a lot like graphite but is actually some hi-tech material. I find that it is good for just about 150 miles, after which the clutch will give a little jerk each time you accelerate from a standing start. The problem is that the roller cams don’t move outward with centrifugal force if they are not lubricated well, and when they do finally move they cause a sudden engagement and a resultant jerk.  My personal solution is to clean the rollers and cams and lubricate them with the tiniest bit of Harley Davidson wheel bearing grease - just a dab on the tip of your finger. To take the pulley apart you will need a dummy keyed shaft that you can chuck in a vice. Then you can drop the pulley over the dummy shaft and use a large end wrench to screw the front part off counter-clockwise. You will see three roller cams and three ramps that they run up with increasing centrifugal force. When you put it back together be sure each cam is centered in a ramp.  I would not advise using grease if you run off-road, but after many hours of satisfactory operation took mine apart for an inspection and the cams and rollers were still clean and dirt free.  An alternate cure is to purchase the 44-magnum driver and remove it’s internal spring to make it engage in the proper RPM area.

Where can I find polyester loom for wiring harnesses?
The polyester loom is ideal to make professional looking wiring harnesses. You can get it from "The Great Atlantic Aeroplane Company, Inc. in Avon Park, FL, Their telephone number is 863-453-5131. They have it in 1/4 inch, 1/2 inch and 3/4 inch. It is expandable, and each size will accommodate a wire bundle slightly larger than the stated size.  The part number for 1/4 is ES14B and 1/2 is ES12B.  The 1/4 is just right for the dimmer switch, etc. and the 1/2 will handle a full Vanguard main cable harness. A diagram of a wiring harness that I built for a 1959 Vanguard Eagle is posted at this web site, and a printed copy is available for a SASE.

I dropped a bolt down in my engine. What now?
It is very easy to drop a screw or loose change down the in the "V" at the top of the engine. Any small bolt or foreign object that is dropped there will settle on or under the coil in the alternator. Then when the engine is started it will either tear up the coil or will wedge up behind it and short it to ground.  Presto - little or no charging current and usually a burned up regulator. It is a shame that Briggs & Stratton made an engine with this susceptibility. If this happens to you do not turn the engine over. Remove the shroud and the flywheel and remove the foreign object. This happened to me at the Cochran meet last year. I don’t even carry change any more when I ride the Vanguards.

How do I get the Flywheel off?
Look behind the flywheel. If it is an 18 Hp it will usually have a strange looking ring of metal with notches cut out that is mounted under the rope starter cam.  A special tool is used with this notched ring to hold the flywheel so you can take the nut off or put it back on.  If it is a 16 Hp you have to find a large strap wrench to hold the flywheel because it will not have the notched ring. The only way to pull the flywheel is with the flywheel removal tool from Briggs. It is a strong bar of metal with two holes and two hardened studs. The studs thread into the existing holes in the flywheel and then the large bolt at the center of the puller forces the flywheel off. You can see one in the Briggs service manual. It is pretty easy to make the puller, very difficult to make the cam device to keep the flywheel from turning. You will need a calibrated torque wrench that can read 125 Ft/Lbs to put the flywheel back on. 

How can I advance the timing?
You can mill 1/10 inch off the side of the key and it will advance the timing about 10 degrees. You mill only the part of the key that extends above the crankshaft. See the article about this at the Hints & Tips page.  

What else might I need?
You may want to consider a Tiny Tach tachometer available from Briggs & Stratton dealer. It is very helpful to make sure your Comet system is adjusted properly. Also you should put a leg protector on the exhaust pipe under the seat area. One of the small aftermarket speedometers is ideal for a Vanguard. You can also purchase an adaptor ring to make it fit right into the Eagle dash plate.

Where can I get more Vanguard Info?
You can go to www.briggsandstratton.com and download the free illustrated parts list for your model, type and code engine. These numbers all appear on your engine tag. You can also buy the manual “Repair Manual for Vanguard V-Twin Overhead Valve”, part number 272144, from any Briggs and Stratton dealer for about $15.00.


1. Thanks Bill Predock for the tip on removing the plunger and spring.

2. Thanks Tommy Manning for finding these part numbers.

3. Thanks to Bill Predock for the tip about cutting off the oil drain plug.

4. Premium #40 chain is available from Steve Lorenz at Arcadia Cushman. See the Dealer page at this web for contact information.  Thanks again to Bill Predock for this tip.


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First published 01/15/03
Revised 01/18/03

Copyright 2003 Jim Frederick. All rights reserved. May be reproduced for non-commercial purposes if copyright notice is retained and credit is given.