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MotoIQ Project Ruckus part 6, the final chapeter is now live!

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  • MotoIQ Project Ruckus part 6, the final chapeter is now live!

    Project Honda Ruckus Part 6: The Final Option, Tuning the Transmission

    By Jeff Naeyaert

    Good transmission tuning info no matter what sort of scoot you have.


    In our last installment of Project Ruckus we got our super motor tuned and running well, however although our acceleration was vastly improved, we did not see much of an improvement in top speed, only gaining about 3 mph before hitting the 10,500 rpm rev limit. To make matters worse, our Ruckus is now always topped out on the rev limiter. Doubling our power has enabled our bike to zoom right on up to its top speed but once that speed is reached, the engine is screaming at 10,500 rpm continuously. This probably is not the best bet for long life!

    Read the Series Here!

    The Kitaco final drive gears raise the gear ratio from 3.5:1 to 3.15:1. While this gives more top speed, it also slows acceleration.

    The engine badly needed to gear up to make the best use of its newfound power and to make the driving more flexible with more top speed and less stress under cruising conditions. We purchased a Kitaco high gear kit from Bowls which raised our gear ratio from the stock 3.50:1 to a higher 3.15:1. While we had the transmission apart we WPC treated the Kitaco gears and the stock intermediate gears to reduce their friction. (To read how WPC works, click here) Since we are dealing with a low powered engine, we are trying to give it all the help possible.

    We used Motul synthetic lubricants for all systems on Project Ruckus. After assembly, we filled the gearbox with Motul 300V 75/90 synthetic gear oil to try to reduce friction even lower. Between the WPC and the oil, things are much freer and you can noticeably feel the difference in drag when spinning the rear wheel by hand or when rolling the Ruckus around. The WPC reduced the rolling resistance by about half and it was amazing that the difference could be so easily felt.

    The WPC treatment gives the gears a lustrous finish. The smoothness greatly reduces friction and wear.

    The gears helped reduce the engines screaming greatly and the bike was becoming really fast, able to now exceed 58 mph on the flats and easily cruising at 50 mph without strain. Unfortunately this flexibility came at a loss in acceleration. Sure Project Ruckus was still much faster but we missed the quick hole shot acceleration of the stock gears. Worse yet, our clutch that had been slightly slipping was starting to get worse. It was time to do some more tuning of the drivetrain to get our acceleration back.

    The difficult part of changing the gears on a Ruckus is knocking the pinion shaft out. We used a socket the same size as the bearing ID and tapped it out using a hammer. The new part installs like the old one. Be careful to only contact the outer race of the bearing so you don't ruin it. The new gears simply install as shown under the cover. Grease the shafts with the supplied red colored lube that comes with the gears.

    The Dr Pulley clutch was chosen for its wide range of adjustably and the ability to raise the engagement speed without increasing slip.

    After some research, we decided to try the Dr Pulley Clutch. Prior experimentation had been done by Battlescooter with the KN Kikaku clutch but the test bikes lost top speed. We theorize that this was because when stiffer clutch springs were used to improve launch, the stockish Ruckuses that were used for testing didn’t have enough revs to fully lock the clutch and top end slippage resulted. We knew that we would need a lot of tuning flexibility so we selected the Dr Pulley clutch as this is the most adjustable clutch on the market.

    We used a 50cc GY6 clutch bell as it has the larger 107mm Dr Pulley Clutch diameter with the same pinion shaft splines as the Ruckus. We machined 0.100" off the center post where the pinion shaft slides in to get the bell to sit more inboard so all of the clutches shoes would contact the bell. You don't have to do this but the clutch will work slightly better and possibly last longer if you do.

    The Dr Pulley clutch is awesome because you can adjust the stall speed of the clutch via the centrifugal springs on the shoes. These control the clutches engagement RPM. We wanted to raise the launch rpm to make up for the sluggishness caused by the higher gear ratio. This would get our Ruckus moving right as the engine was getting into its powerband. What makes the Dr Pulley cool is that it can totally lock up solidly even with a high engagement speed. With other race clutches, when stiff springs are used to raise the launch RPM, the clutch looses centrifugal locking force. This makes them slip more, not exactly a combo for good top speed or acceleration. Dr Pulley clutches have a cam wedging device that mechanically locks the clutch shoes on the drum once they are engaged by using the engines torque driving force to help lock the clutch. Thus the Dr Pulley is the only clutch that can have both a high launch RPM and a solid top end lock up.

    The Dr Pulley clutch on the left has shoes much bigger than stock stock clutch on the right. Plus there are three of them vs the stock two. The friction material is also a more performance oriented semi metallic material vs the stock cardboard like stuff that the stock clutch uses thats designed more for smoothness. As you can see the stock clutch is all glazed from slipping with our powerful modded engine. The Dr Pulley clutch is bolted to a Yamaha Jog/Zuma contra pulley to make it work with our Ruckus.

    The rpm at which lock up occurs and how hard the clutch locks up is adjusted using an additional set of springs called pillow springs. The pillow springs counter the engines torque and reduce the cam wedging action. The stiffer the pillow springs, the higher the lock up rpm and the smoother the lock up will be. The Dr Pulley clutch has a much more durable semi metallic friction material as opposed to the cardboard like stock stuff. It also has 3 shoes as opposed to the stock two and about 3 times more shoe area that stock. This clutch will probably last forever on a Ruckus!

    To help tune the transmission, we used a Malossi red high tension contra spring from a Yamaha Zuma to slow upshifting. This keeps our cammed out modded engine in the powerband better, reduces belt slip and lets the transmission downshift better on the hills. We also used a Malossi torsion controller bearing from a Zuma which helps smooth out transmission operation. To install the contra spring is a two guy operation, one person has to compress the spring while the other tightens the lock nut down with an impact.

    Unfortunately Dr Pulley does not make a direct bolt in clutch for the Ruckus so we had to use some parts swapping trickery to use a common Minarelli Dr Pulley clutch on our Honda. This is the same clutch used for a Yamaha Jog or Zuma so these tricks can be used to adopt any performance clutch for these scooters, like a Polini or a Malossi although we think the Dr Pulley clutch works the best. We obtained our Dr Pulley stuff from Vince at Scooter Dynasty who was very helpful in contrast to the distributer MRP who hung up on us. Vince got us our parts quickly and at a good price.

    To tune the Dr Pulley clutch to the high revving characteristics of our built engine, we wen up two stiffness levels in clutch spring stiffness to raise the launch rpm. We also removed the pillow springs as shown here to get maximum lock up.

    We removed the entire stock Honda clutch and contra pulley and replaced it with the Dr Pulley clutch and Contra pulley from a Zuma/Jog. As the Dr Pulley clutch is bigger in diameter than stock, we had to use a clutch bell from a 139QMB scooter which uses the small 50cc GY6 engine. This bell has the larger 107mm diameter of the Dr Pulley clutch but the same pinion shaft splines as the Ruckus. We machined 0.080" off of the mounting boss of the bell so it would line up perfectly with the clutch shoes. This isn’t absolutely needed but we wanted to use every bit of the clutch shoe engagement.

    When installing the Dr Pulley clutch, you have to add a spacer to the pinion shaft or the Jog contra pulley will bottom out on the transmission case and get bent when you tighten the nut. Don't bother to call MRP about this problem, they don't show you this in their tech video and they will hang up on you if you call! We ground down three washers to fit inside the contra pulley without rubbing to act like spacers so the pulley could spin freely without hitting the tranny case.

    When installing the Zuma/Jog Dr Pulley clutch you have to shim the pinion shaft to prevent the contra pulley from hitting the gear case. We used three washers and ground the ID to fit inside the contra pulley. Later Scooter Dynasty came out with a nice spacer to make this easier so if you order this clutch, be sure and get the spacer.

    When testing the clutch we could immediately see that this had a lot of potential as all slip was eliminative and the launch speed was raised slightly. We had to do more tuning. The Dr Pulley clutch comes with a big assortment of springs for tuning the launch and lock up rpm. The clutch is shipped with the softest blue spring in place. This spring started to engage at 5000 rpm, and grabbed at 6500 rpm. We needed more to get the engine into its powerband and opted for two steps stiffer, the yellow spring. This spring started to engage at 5800 rpm, and grab hard at around 7500 rpm. We also removed the pillow or lock up spring entirely for the hardest lock possible.

    Later we got this spacer that Scooter Dynasty had made to do the job correctly. This spacer is pretty easy to make but its cheap and easy just to buy it.

    This made a big difference, launching our Ruckus hard out of the hole and moving down the street while still maintaining street drivability. This got us about half of our acceleration back. We still felt that the combination had issues; the transmission shifted up too aggressively and didn’t respond well to hills. Our engine once launched, was held at too low of an rpm, right when the engine was starting to come into its powerband but still at slightly to low of an rpm for optimal acceleration. We needed to make the variator more sensitive to load and to make the upshifting curve better match the higher rpm biased characteristics of our modified engine.

    We did this in several ways. First we disassembled our Polini variator and sent it to WPC for treatment. The WPC treatment reduces its operation friction on the shaft and rollers which helps the variator be more responsive to changes in load. The WPC also helps the drive belt grip better and helps the belt face resist wear and grooving which also hampers variator operation.

    We WPC treated the variator the pulley faces for Project Ruckus to help the aluminum to resist wear and to help the belt grip better. The treatment gives the pulley faces a smooth, creamy textured look.

    Next we changed contra springs. The contra spring controls the tension on the drive belt. The stiffer the spring the slower the transmission will upshift and the less the belt can slip. The transmission also becomes more sensitive to load and will downshift on hills better. When an engine is modified for more top end power, adding a stiffer spring helps. We used a Malossi red spring for a 50cc Yamaha Zuma. The red spring is the stiffest of three available springs from Malossi. We also used a Malossi torsion controller bushing from a Zuma as well. The torsion controller bushing allows the contra spring to compress freely without bind. This allows the variator to upshift and downshift more freely and smoothly with greater consistency. We got these Malossi Zuma parts from Provo Scooters.

    We also WPC treated the inside of the variator, the shaft and the ramp plate. This reduces the variators internal friction and makes it more sensitive to load and allows it to work more smoothly. This complements our contra spring tuning.

    We assembled everything with Dr Pulley 4.5 gram sliders in the variator, lighter than the 6 gram slider we had been using. The lighter sliders will delay upshifting and help keep the engine in its powerband better. We feel that sliders from 4-5.5 grams will work well for someone with an engine modified to the same extent as us. When WPC treating the variator, you will need to use lighter weight rollers/sliders as the variator becomes more responsive due to less internal friction and will upshift too aggressively, boging the engine with heavier weights.

    We used Dr Pulley variator sliders to tune our variator. The Dr Pulley sliders allow the ramp plate to sit 0.020" lower in the variator at rest. This give a lower gear ratio out of the hole, improving low speed acceleration. We ended up settling on 4.5 gram sliders to tune our variator to our engines powerband and our weight.

    With these final changes, all we can say is WOW! Our acceleration is now close to what it was with the stock gears with additional top speed and easier cruising at 50 mph. Our scooter also performs well in the hills, pulling a 200 plus lb rider up the steepest hills without dropping below 35 mph ever no matter how steep the hill. Our top speed of 58 plus mph can be reach repeatedly. With a lighter smaller rider, we feel that the Ruckus can probably hit 60 mph. We have turned our Ruckus from an anemic pit bike to something that is a useful commuter that can handle anything below a freeway. After several thousand miles, we are proud to report that our Ruckus is also stone reliable. It still get around 85 miles per gallon, down from around 95 mpg stock but note that is probably going much faster as well!

    Are we done? For now yes but we have other Ruckuses being built right now in the Palatial MotoIQ garage. We are going to try further development of the GET engine on another chassis to reach our goal of 60 mph. We have some sick engine swaps in the works as well, both two stroke and big 4 stroke. Stay tuned!
    Last edited by John; 29-12-2009, 12:51. Reden: Added content

  • #2
    i hope the next chapter will come sone, i am looking forward to it


    • #3
      nice project guys are real pros
      when are you guys going to do a european zoomer with 4valve+injection engine?

      think that engine wil make more power