Power band problems

[superc]

So I am nearing the end of my build. A 70cc Athena kit, carbon fiber reeds, Technigas exhaust and I put it all on a new frame. Welded on a new seat and changed the angle of the handle bars.

I took it out for a first run last night and it's fast. Very fast but....

I still have a power issue. Out of the pocket it kills and gets to 20 quick but then has a lull to 30 and takes off to 40. I haven't had a chance to really open up the new motor because of the break in.

What can I do to have a nice steady acceleration across the board?

And yes that is a tractor seat. I stole the idea from someone here I believe.

Thanks,
-C

Attachments:

[90GTVert]

If this is all with the throttle in the same position, I'd say it's a CVT tuning issue. It sounds like your clutch is good, since the first 20MPH is fast. I'd try out different roller weights or sliders and clean and regrease the torque driver to be sure it's working right.


Looks cool BTW.

[jmkjr72]

when my zuma did that i swaped out the contra spring to a stiffer one
it could also be the angles on your torque driver
but that is as long as your carb is tuned right

[vvtr]

i'd check the clutch pulley (torque driver as brent says) assembly is free and not gummed with dirt and belt debris.
could be it's accellerating well off the variator but if the clutch pulley isnt separating you won't hit the higher gearing.

you could start it up with just a few bolts in the vari cover then pop it off and check its all working as it should.
it should work like this


i'd kill for a fuel tank that big lol¬

[superc]

Feb 26, 2012 8:25:58 GMT -5 vvtr said:

i'd kill for a fuel tank that big lol¬

It's funny you say that. This all started because the first moskito tank rusted out and I could not find a new one. And out of the ashes this thing was born.

---------
I changed the weights out from a 6g to the stock. I am not sure of the weight. (I have quite a few rollers around and I am going to stop by office depot on the way home to pick up a scale.)

So with the stock weights I have a somewhat even acceleration (slower than before) and still have a pick up around in the tail end. I haven't had the time to run the CVT with the cover off.

I also am a little nervous about the jetting. I am still running my stock jet @ 77.5 and pre-mix at 50:1. I did the spark plug test and the first short WOT and There was light brown to residue on the plug. It looked consistent with some photos I have seen here. It runs like a champ and starts on the first kick. Idles perfectly. I ran it at near WOT for about 20 minutes averaging 45-55 mph and it was flawless.

However, the more I read on here. The more I get scared that I have something wrong. It seems like I should be a little lean. Should I just try a larger jet for fun or let it ride?

Lastly I am NOT using the head gasket simply because with the gasket that came with the kit the squish was around 2mm. The instructions called for 0.90mm which was achieved, however I just used a thin bead of gasket maker and ran with it. I hope that's cool.
-C

[90GTVert]

I wouldn't worry about being too lean on the main if you've done 20 minutes of WOT. It woulda seized for sure if it were too lean. You could always try a step up and see if you get any improvement, but the WOT circuit sounds pretty well in tune.

[2strokd]

Nice scooter! I like the way you think!
Ive got a bunch of those Miskito style tanks for sale now.

[vvtr]

77.5 lol mines on a 180 atm & still feels lean!

[stevo52]

I ran a 77.5 when I had the stock carb, 70cc and pipe. Plug chops where fine. I wouldn't worry about it.