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Post by 90GTVert on Jun 9, 2011 11:07:12 GMT -5
One cause for a little MPH loss when comparing a 70cc kit (especially with a pipe) to a 90cc is gonna be RPM loss with the 90. These things are more comfy somewhere around 7-8000RPM without port work and pipes. The 70kit with a pipe was more likely welcoming 9-10000RPM. Heavier rollers and sliders than our 50-70cc setups liked should be able to make up for that for the most part though. I'm not getting anywhere near full travel with a stock variator on Project 90. I'm maxxing at 51MPH, but I have 10:125 gears. Didn't you say this thing had 13.55?
The only stock vari I ever owned that had complete travel of the vari was the one I cut up so the rollers could reach farther out. The Hoca vari on the other hand, I can get those suckers to travel the whole face with mods and if I go far enough it'll start snapping belts. lol
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Post by drawkward on Jun 9, 2011 14:16:40 GMT -5
I did figure the RPM loss, but like you said; that's where the weight of the rollers comes in. I've been to both extremes - 5g (very light for this motor), and 13g (slugggggg). Still not getting full ride. If I could take a picture I would show you the marks I have two of my vari faces - both showing full travel was reached at some point. I also have different length drive bosses, and I feel like I can see a difference in the ramp plates I have, but I'm probably just imagining it. I've tried so many combinations with all the different vari components and rear pulley components trying to root out the problem. The only thing I haven't done is try to space the vari face with washers, because I figured that would cause less travel for top speed, even though I would get the belt on the edge of the rear pulley.
It is a mystery for me right now. I'll get my 70cc up and running when I get the carb situation figured next week, and see if it's just an RPM thing.
I feel I'm obligated to mention that it is running rich and wet throughout the range. I know this isn't the problem, as it's not a power issue. I go down hill and overrev just to hit nearly 50.
And yes I do believe it is the 13.5:1 ratio gear set; come to think of it - all of my gears are long. Nice. It's gotta be a vari issue. I mean there's clearly something wrong when my belt is sitting inside the rear pulley a good bit at rest, and not even close to drive boss.. That's not normal for me to see on my set ups even when stock.
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Post by 90GTVert on Jun 9, 2011 14:31:12 GMT -5
The weight of the rollers or sliders will only get you so far. I just spent the money on some 9g sliders for the stock vari to learn that for sure, and just came in from trying it. I was hitting 9000RPM at max speed with the heaviest sliders I had, 7g. Swapped up, 9000RPM at the same max speed. What changes? Everything under 40MPH or so. Below 40, it gets sluggish. Then you get to full travel which is right in the neighborhood of 40MPH for me with everything stock and revs increase. By the time I'm at max speed the revs are the same with 2g heavier sliders.
What that boils down to is that the stock setup of the variator is only going to push the belt so far, thanks to poor design. You can kill your acceleration all you want with big heavy rollers, to a certain extent it just doesn't matter. At max travel, you are locked into a "gear ratio" with the front and rear pulleys. That coupled with engine RPM and final drive ratio are what determine your max speed (assuming plenty of power is present to not be a limiting factor).
So you absolutely must increase the amount of belt travel you get. As I said earlier, the easy way is to get a good variator, or if you have plenty of money to spend go get a whole overrange CVT setup. The harder way is to start working on that stock variator and drive face until you figure out how to push the belt out farther. The best way I have seen to make the belt push out farther in the stocker is to cut it so the rollers can move a litter farther, like I said before. Face mods can help too, and they can really help you get the belt down in front. Modding the torque driver can be helpful too. There's more info on some of this stuff in my Project 90 thread.
None of my stock setups will put the belt real low up front or high out back. Pics of that as well in the Project 90 thread. So much of this CVT stuff is trial and error and sacrifice unless you have good parts.
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Post by drawkward on Jun 10, 2011 8:38:48 GMT -5
Never give up, never surrender!
Plus I'm broke, so... Gotta make it work!
I'll figure this one out ;-)
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Post by drawkward on Jun 25, 2011 12:33:19 GMT -5
I developed a fuel issue (think my main is clogged, or my old dry rotted intake that I repaired with RTV is leaking again). Obligatory back story: I stopped and filled on my way to work. Premixed as usual. Went to work, clocked in, busted my ass for a few hours, and clocked out. Started up the scooter and took off. Rode fine for a few blocks, then started lean bogging HARD. Anything over 1/4 throttle has been lean bogging. Checked the usually oily black plug and it was still black, but dry. Had to ride it home with my finger over the airbox hole. Not fun, I have short arms so it was a bit of a stretch. The fuel filter has a tiny bit of leaf in it. Got a new one, need to fit it. Also need to empty and clean the carb. Haven't had time, hopefully I can do this afternoon and that it solves my problem. Now that I typed it all out, it seems to be plainly obvious that it's a clogged main. My theory: Letting it sit at work allowed the leaf to settle down in the tank. After starting and taking off, the leaf took a few moments to work itself down into the carb. Then the "lean bog" began. I need to order a new intake so I can fit the OKO carb I got for cheap onto it and get it roughly tuned so I can be ready for my new peace pipe in the works. I know it's a lot of pictures, but I wanted to make sure I got atleast a few good shots that were in focus. Do you guys know anything about this piece? I have no idea where to get jets for it. It's 26mm ID on the engine side, by the way. Once I get the OKO carb on it, I can fire up my 70cc build. You guys happen to know where I can get a jet set for this carb? Or even just any jets? I don't have a clue. I'm sure jetsrus.com carries them, just I don't know what jets would work. I know I can measure and check, and I will do that if none of you guys happen to know. Was just running it by you guys! Oh and I also have a Mikuni VM26, but it needs a few parts as well. |
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Post by lshigham on Jun 25, 2011 12:39:49 GMT -5
Look for Keihin hex jet's for the OKO, they're identical. Any idea on what size it is? I know you said it's got a 26mm id, does that carry straight on through? They are available in 26mm, but are rather rare.
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Post by drawkward on Jun 26, 2011 0:15:56 GMT -5
I need to double check the size on it. Thanks for the tip for the jets.
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Post by drawkward on Jun 26, 2011 0:35:38 GMT -5
Anyone with recommendations for jet kit numbers? Shoot for 100's and up for the main? Pilot?
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Post by lshigham on Jun 26, 2011 4:02:43 GMT -5
A pilot of 40 will get you close enough to adjust it with the mix screw. If it is a 26mm, look for 110-130 main.
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Post by 2strokd on Jun 26, 2011 9:30:31 GMT -5
I ran dello21mm carb jets in my Keihin 28mm. I think they are 5mm ones? Not sure, im not at home now and cant check for ya, sorry...
BTW, your gonna love that big mina with a Peace Pipe!
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Post by drawkward on Jun 26, 2011 15:20:20 GMT -5
If it is a 26mm, look for 110-130 main. Ok that's what I was hoping to hear. I couldn't find anything under 100. I'm assuming those sizes would still apply to me if I was using an aftermarket pipe and open filter? I've also got the cases trenched - not sure if that affects jetting. This carb came off of a 110cc 2 stroke dirtbike, so hopefully it's got a useable pilot - I'm thinking it should be pretty close, as I'm 96cc and going to be using a hard hitting pipe with long durations...? I wish there was a formula for all of this so I could just punch in some numbers and get a rough jetting recommendation! |
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Post by lshigham on Jun 26, 2011 15:30:55 GMT -5
Those were based on a pipe and open filter, yes. An airbox knock's them right down.
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Post by drawkward on Jun 26, 2011 15:32:29 GMT -5
I ran dello21mm carb jets in my Keihin 28mm. I think they are 5mm ones? Not sure, im not at home now and cant check for ya, sorry... In the same boat. If I was at my grandmothers (where my shop is), I'd be able to simply measure and check. I remember they are the long hex type jets, so I'm sure this jet pack would be sufficient. BTW, your gonna love that big mina with a Peace Pipe! I know I will. I slapped a cheapo 47mm autotech top end on a stock bottom end, threw a used beat up Leo Vince on it, and was impressed. Now I'm going to be putting a custom built race pipe on a cheap 54mm that's bolted to a bottom end that's been port matched and flow optimized. I. Can't. Wait. Slight set back... Broke a stainless steel bolt off in the cylinder's exhaust header. Then I broke the extractor inside that bolt. My dad decided to borrow my new welder without asking, and can't get it back to me for a couple days. Should be fun to remove! It's actually holding up pretty well with just one bolt for the exhaust, for now. I just gotta make sure I keep an eye on it, as it tends to creep on me. |
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Post by drawkward on Jun 26, 2011 15:39:26 GMT -5
Those were based on a pipe and open filter, yes. An airbox knock's them right down. Nice. Yeah I've been avoiding the open filter until now, because now I think with the larger displacement and pipe, it might actually make a decent improvement in power output. |
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Post by lshigham on Jun 26, 2011 16:14:25 GMT -5
You won't get an airbox on the carb anyway, so you won't have much choice in the matter.
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