2008 Zuma - The Keeper, Always Evolving

[ryan_ott]

After 4 attempts I’ve come to the conclusion I need thicker o-rings.

[oldgeek]

I doubt I would have the patience needed to go LC. You guys go through so much.

[ryan_ott]

Sometimes they go together well, sometimes not so well. The Malossi cylinders I’ve had in the past never had any sealing issues, I just have other issues with their cylinders... Going LC in concept seems easy enough but to be honest it’s really a pain. AC as long as your in tune and don’t blow apart a fan you’ll be fine. LC you need to worry about coolant, hoses, clamps, seals, o-rings, water pumps... but if it all works well you can run a tad leaner, get better fuel economy and in theory be more reliable. What a joke!!

[90GTVert]

The primary reason that I'm trying to remain LC is that from the time it warms up till the time it shuts down, even if that's 12+ hours later, it runs consistently well... as long as it doesn't blow a head gasket or anything like that. I could never get quite the same results from numerous AC setups that I beat on in similar fashion. It does seem to run a little harder than similar AC builds as well. The juice around the cylinder makes it a little quieter, but it's still a noisy 2T so that doesn't matter a whole lot. I seem to be doing quite well at wearing out cylinder kits still and I'm getting 30MPG, which is as bad as I've ever got.

[pinkscoot]

I really admire both of you. Both my LC 50's are that way from the factory so a lot of the pain that you have both gone through has already been engineered for me. I am following you both with great interest because I hope to one day do a LC build with my ET2.

[tsimi]

AC and premix is a dream to work on.
No oil tank or oil hoses, no coolant.
Just very easy and quickly to take apart to repair or maintain.

LC is a friggin nightmare but it has its rewards. Most of the strong racing cylinders are LC.
Once setup they are very nice to drive and look awesome with those radiators.

Still if I ever had to build another engine I would go AC premix just to avoid all the hassle with the hoses and coolant.

['O'Verse]

I'm Liquid cooled for life. I'll never touch another set of cases that aren't C-one, RC-one or better. Carter just built a 70cc C-one the other day. I thought I had meat around the cases for a sealing surface. The C-one and 70cc Testa Rossa has like a inch all the way around the cylinder of sealing surface. No more leaky base gaskets. If the cylinders built well no more leaky head gaskets. Get some quality hose clamps and top off your coolant every so often. At 150 degrees you couldn't even cook dinner. 😂 Let alone a piston or cylinder.

[ryan_ott]

In between test runs I pulled the pump cover to see how the pin and adapter are holding up. This is after 5-10 miles. It’s pretty amazing what can happen to that pin just from the impeller hitting coolant. I’ll try a dab of gasket sealant to see if it’ll act as a cushion. In a few miles I’ll pull it and see how bad it gets.

[90GTVert]

This stuff would probably need to be different materials or hardened/treated to hold up is my guess. I'm just using the titanium 1/8" pin with otherwise stock stuff ATM.

[ryan_ott]

I just got back from a 45 minute shake down. It’s still alive. Now I remember why I go through brake pads so quick. The CVT and/or clutch need work. Does the larger OD of the TD I’m using translate to slower clutch speed? I’ve had low take off rpm with the Polini 3G maxed out, so I switched back to my HiT and it’s better but it’s still low. I think I also need lighter rollers. Jetting is also a little rich. It was still an enjoyable ride that was well needed. Coolants temps were 135-145, CHT 215, EGT maxed out at about 1030.


Got to love those cold 2 stroke starts!

[90GTVert]

Jun 20, 2019 18:12:11 GMT -5 ryan_ott said:

Does the larger OD of the TD I’m using translate to slower clutch speed? I’ve had low take off rpm with the Polini 3G maxed out, so I switched back to my HiT and it’s better but it’s still low.

The size of the rear pulley should change the speed that the clutch is driven at, assuming the belt makes use of the extra diameter. It should actually have the opposite effect of what you're describing though. Having a larger, or effectively larger (from belt position), rear pulley should result in slower clutch speed... not lower engagement though.

Let's say you had your clutch setup to engage at 8000RPM. Remember that pretty much all of us are talking about engine RPM when we state clutch engagement, because I don't know anyone that monitors their actual clutch RPM. Clutch RPM would be engine RPM in conjunction with whatever ratio the CVT is in at any given point... prob with some variance from slippage. Maybe at idle the rear pulley and clutch are rotating half as fast as the crank, 2:1 engine RPM:clutch RPM, so your clutch RPM would be 1000RPM if the engine idled at 2000RPM. Since the CVT is continuously changing ratios, it's hard to know exactly where it is most of the time.

Anyway, back to that 8000RPM (engine) clutch engagement setting. Just for demonstration purposes, I'll say the CVT is 2:1 at idle and stays in that position till the clutch engages at 8000RPM when the clutch engaged with one pulley, so the clutch was turning 4000RPM to the engine's 8000RPM. So the actual engagement RPM for the clutch is 4000RPM... meaning the clutch itself has to turn at 4000RPM to engage. Remember that the springs and such in the clutch don't know how fast your engine is rotating. They just act based on forces directly on them.

Now you go and install a larger pulley and a belt to make use of that larger pulley's OD. Maybe now the front pulley has to rotate 2.5 times to spin the big rear pulley around at idle and sticks there till the clutch engages, so you're at 2.5:1. If that's the case, when the engine is at 8000RPM, the clutch is now at 3200RPM (8000/2.5). So if that clutch doesn't engage till it spins 4000RPM, it's not ready to engage yet. The engine is going to have to make it's way to 10,000RPM in order to turn the clutch at 4000RPM, so that clutch isn't going to engage until 10,000 engine RPM now.

It's not actually that cut and dry, because so much stuff is happening and your CVT isn't really going to sit totally still till whenever the clutch decides to engage. Maybe that gives you an idea of why the clutch would normally engage at a higher engine RPM and feel more loose or free when swapping to a larger pulley with adequate belt travel. This is what I have experienced with my OR kit. I have always had pulleys act as if I installed stiffer springs relative to their operation with stock sized pulleys.

Aside from that, you can get a torque multiplication from the change in effective ratio which is similar to the effect of having deeper (numerically higher) gears in the gearbox for takeoff. So that can also make the clutch feel better.

Long story short, I'm not sure why you're clutch is engaging at lower RPM now. lol I would probably see what happens with lighter weights in the variator, especially if you don't think RPM is where it should be during the rest of operation. Some variators can also sort of slip in a way that resembles clutch properties. I have installed OR variators and it felt like all of the sudden I put in an aggressive clutch setup with no other changes. The Malossi OR vari is what I've been using and I cannot make my scooter take off at low RPM. I have tried ridiculously heavy weights that kill performance everywhere else and the thing still skips all the low end on launch. Perhaps make sure nothing bad is up with the variator, like the boss isn't moving smoothly or something like that.

[ryan_ott]

I can always swap back to the stock TD to see where rpm is with no change to the clutch. The 3G with the thickest springs at the tightest notch I’m only getting about 7,000 rpm, my HiT with purple springs is about 7,800 - it should be higher but the springs grooved the clutch lowering rpm. I really just need a new Hit clutch. One change at a time... cruise rpm is also down - lighter weights/heavier TD spring. I’m using a Malossi yellow TD spring which worked well in the past but I’ve got lots of others to choose from. As long as I can get the initial engagement up I can deal with the rest, it’s just finding the time with everything else I’ve got going on. Hopefully this weekend.

[tsimi]

Not easy, but try to source a Polini 2G Evo clutch. Those are fantastic to setup and can easy engage at 8000+ rpms.

I use the 105mm version on my Prebug and the 107mm version on my Roost LC build.

For me the HiT clutch springs faded too quickly. A few power take offs now and then and the springs become soft.

[ryan_ott]

She’s back and better then ever... almost.



I only made one change and it has a seriously positive effect, I dropped my main from a 88 to a 86 and it seems to make all the difference. It’s also very cool out which may also help but I went through 2 tanks of fuel and I’m very happy with it. Still the clutch could engage a tad higher but I’m ok for now. Maxed out at 63, 0-50 is pretty quick, temps are still 135-150, CHT 215-230, egt maxed out at 1070. I may drop another size on the main. I’d like to go to a 38 pilot but my seems to be missing so I’ve got a 40 in it, 36 seems too low to me.

[repherence2]

Jun 21, 2019 22:08:19 GMT -5 ryan_ott said:

She’s back and better then ever... almost.



I only made one change and it has a seriously positive effect, I dropped my main from a 88 to a 86 and it seems to make all the difference. It’s also very cool out which may also help but I went through 2 tanks of fuel and I’m very happy with it. Still the clutch could engage a tad higher but I’m ok for now. Maxed out at 63, 0-50 is pretty quick, temps are still 135-150, CHT 215-230, egt maxed out at 1070. I may drop another size on the main. I’d like to go to a 38 pilot but my seems to be missing so I’ve got a 40 in it, 36 seems too low to me.

that's a beautiful bike!