UM Xpeed 50 r

[jimh]

Got my 17x12'sfrom Monster, 6gr, and installed them today. They were noticeably bigger than the 15x12's. Takeoff is much the same but top end is off the hook! I was literally cruising at 3/4 throttle@ 43mph, 47-48 on small downgrades. Guess the question about 2mm difference has been answered. I first got curious when my friend with identical bike was making claims of 47 mph with the same set-up as mine and he told me the size of the rollers/sliders was not 15x12 but 17x12. Don't exactly know why but the rollers that were in it originally were 15x12 so I assumed they were a proper fit. Check and double check. Something else I noticed with the new sliders is I don't hear/feel that annoying harmonic surge that I was experiencing at higher speeds. All is well and my little 50 is running 45mph without a great deal of sweat. That's more like it, mo betta!

[90GTVert]

+5MPH and a smoother ride! Congrats. ;D I would think it might reduce future wear inside the vari as well.

[jimh]

I think so too, Brent. The rattling at idle is gone as well. Honestly, I was at a point this summer where I thought about giving up on this scoot and buying a new one but not being rich have decided to hang in there with what I have and continue to improve it where possible and just be happy I have a driver that gets me around without breaking down. Still debating on the BBK at a later date but enjoying the present mileage. If I could fab a 2 1/2gal gas tank the BBK wouldn't be problematic.

[90GTVert]

Do you just want longer between fill-ups or do you have long distances to cover where gas stations are scarce?

[jimh]

Just more time between fill-ups mainly but have been caught short on fuel occasionally; I do have a couple of 30 oz MSR fuel bottles but a larger tank would be nice.

[jimh]

Hey Brent, I have a buddy over here in Denton with the same bike as me...he put his new 6gr sliders in and decided to use his impact gun to tighten his variator nut and stripped the darn threads. He's sick over it man! Now he has to pull the motor, split the cases and replace the crank. Bad luck; he wanted to get some fast riding in before he loses his leg and won't get to it for several months now. He and I always tighten the variator nut by hand and just the once, killed the crank, buggers!

[90GTVert]

That sucks. You should try to re-thread it to a smaller thread. Metric or standard, doesn't matter. I've done that twice to avoid replacing crankshafts, both times also because of impact guns. After that, I bought a torque stick to limit the force applied when I use the impact.

The sizes prob aren't relevant to your engines, but this one was re-threaded to 7/16". It worked for quite a long time, but I go a little easier on 'em since they are smaller threads. Also, if there are clearance issues on the end, pick up a half nut at the local hardware store instead of a regular nut.

[jimh]

My buddy stopped by today to tell me he said WTH and did just what you suggested, rethreaded the next size down and it worked. Said he applied some blue thread lock and it seems to be holding but he doesn't trust it to hold so is going to do some close to home riding with it till he get's enough confidence that it's good to go. Meanwhile, he is ordering the crank and bearings to have on hand if it does let go. I felt pretty good for him and sent him home with my last dozen Don Elias Dominican cigars and a humidor to keep them in. I quit smoking 4 years ago so had no use for them and seemed a good time to be rid of them.

[90GTVert]

Good to hear. As long as he made nice clean threads and is careful tightening, he should be good to go.

[jimh]

Went riding yesterday and today; the temps were a little on the warm side and my scooter was acting stupid after warming up. At a stop when hitting the throttle it acted as though it was starving for gas. On my way home I stopped by felliotts to trouble shoot this annoying occurrence which has plagued me all summer. He added 2 oz seafoam to my tank, adjusted my a/f mixture and I put a 7 hotter plug in the head and that seems to have cleared up the bottom stuttering I was experiencing. Thanks Frank

[90GTVert]

Now you're wishin' you had stopped in there a few months ago. lol

I'm about the only person that doesn't seem to swear by Seafoam. I've used the spray on cars before with decent results, but I don't think I've ever actually owned a can of seafom liquid. Not saying anything bad about it, I've just never really messed with it.

[jimh]

Actually Brent, you suggested earlier this summer that I needed to adjust the a/f mix but I was either too busy/lazy so yeah, I wish I'd done something earlier but she's running tops now. I think the scoot is due a decarbonizing procedure but will wait till winter to pull the engine for that.

[jimh]

I've been back and forth on my initial takeoff issues since summer; the stock pipe gives incredible takeoff but lousy mid and upper range, the Technigas gives lousy takeoff but excellent mid and upper or so I thought! The problem is, tuning is an ongoing process...what I've learned is to listen closer to the advice given by those with experience in tuning, don't be satisfied with mediocre results, go the next mile to take the rough edges off and get the results you desire and that the engine is capable of. That said, I was not enjoying the results fully of the mods made to my scoot over this last year. I got together with Bill (builditright) and we have been putting our heads together troubleshooting the issues we have faced on our xpeeds. We have both experienced the same troublesome takeoff issues so what we've done is to remove 3 6gr sliders and replace them with 3 4.5gr sliders giving a combined weight of 31.5 grams. This has allowed the Technigas pipe to work through the entire range, bottom to top, by keeping the revs up. There is a small loss of top end (2mph) but we deal with tradeoffs when tuning. I find it amazing that 5.5gr's makes such a difference in performance...minimal weights and measures affect the entire performance in a major way and can mean the difference between average and exceptional. I had thought at one point that perhaps the technigas was the wrong fit for this engine; I was proven wrong thankfully. Initial takeoff is quick with no lag between low and high, as it (shifts?) the pipe comes on at that point (23mph) and races to top end in a robust and steady pull. Rolling off the throttle to approach a turn is another treat...I tend to accelerate halfway through a turn, now no matter how slow or fast, the variator and pipe pull just the way it should. Can you tell I'm thrilled? Hopefully this makes sense and doesn't come off as babble to you guys...maybe I'm experiencing those Eureka moments that all you tuners experienced long ago. Thanks all for your inputs whether on this thread or others, that's how I learn.

[90GTVert]

Thanks for the update. Learning that fine tuning is the key to the performance you want is a point that I think a lot of people never get to. I used to wonder why roller weights were made in .5g or smaller increments. Who needs to tune like that, I thought. Now I find myself adjusting to .25g on roller weight when I really want the best performance, and in some cases even wishing for variations less than that. The beauty of a CVT transmission is also it's downfall. CVTs have the amazing ability to keep us in a very narrow RPM range for acceleration so we can keep at peak power. Why is that a downfall? Because if you are out of tune, you might miss your peak powerband completely or briefly pass by it as the clutch slips.

Now the real problem with learning to tune this way... you will never be satisfied. lol Once you get to know your scooter and get it just how you like it, any little change will annoy you because you know what it can do.

[2strokd]

Im glad you are happy!
I to wondered why the heck weights came in .?? incro,s but i understand after a
while of tuning several different set-ups. Yep, it an artwork of its own.