70cc Sieze

[cstaup]

Well, I rode 5+ miles back to my house this afternoon at a standard clip , mid to WOT. I pulled into the garage and then SCREEECH....nothing.

"OH !@#$." I thought, I fried the motor. My set up is 70cc T6, 19mm carb C/F reeds, and associated stage 2, all Provo.

I let it cool, squirted a few ccs of Motul in the sparkplug hole, cranked it over, and now will fire and idle, but as soon as I open the throttle (see above ) screech.

I will pull the cylinder this evening and inspect. Whaddya'll think? Do I need to add oil to fuel , or altogether remove the injector and run premix 100%

facts:
190+ miles on stage 2
second tank without adding oil to fuel.
weather getting warm??
Help would be apreciated

Chris

[speedy_scooter]

What pipe and main jet? Air filter?

[str8dum]

I'd pull the cylinder and make sure you arent doin more damage by running it!

[cstaup]

What pipe and main jet? Air filter?
Technigas RS, 95 main

I'd pull the cylinder and make sure you arent doin more damage by running it!

Pulled and being looked at real hard, looks like piston slap. That is just the portions perpendicular to the connecting pin are scored.

[raider]

you may be able to hone the cylinder and just get a new piston and rings... i was able to save my cylinder, but ordered a whole new kit just to make sure.... i don't know if you can get just a piston and rings or not for these things...

fred

[pinkymingeo]

A T6 piston is about $50. You have to decide if it's worth it, or if you're better off with a new cylinder. A cylinder can look really ratty but run fine. If there's a hole in the plating, though, it's shot.

[raider]

where did you get the piston? it's not listed on provo? mine looked fine after honing.... it had minimal scaring below the ring line, the rest was melted aluminum from the piston that honed right off... i was suprised it seized, i ran a plug chop after cruising around town, it was fine, but at high speeds it leaned out and died after a short period...

fred

[vewato]

i have a 2000 Zuma 50 cc stock and i recently upgraded to a 70cc t6 airsal cylinder kit that i purchased from alvertano.com and so far it has run good after i had the main jet bored out two levels (not sure exactly what final main jet measurements are). after several 200 ft test runs at assorted rpms (before boring main jet) i noticed the spark plug was dang near white (incredibly lean) which is why i bored the jet.now things are running quite rich (fat and juicy is the safest way to run) which is very good for break in. my local yamaha dealer bored the main jet for free. try boring the main jet and i think that should help. i also have a technigas 70 cc pipe also. this thing hauls some a#@ now, once i get the clutch rollers and springs in, alvertano said i could reach 55 to 57 mph. i can see it definetly has the potential. carburator adjustments are very crutcial especially during break in

[Arlino]

vewato did you use a stock carb?

[vewato]

yes stock carb i just modified the main jet (up two levels) according to the dealer that did it. should i worry? the mods have not even 10 miles, should i still be worried is there any new carb modifications that i should keep in mind? Any advice is well appreciated. Thanks

Dagan

[Lennox]

with the 70cc AND an expansion chamber pipe, you really NEED a bigger carb

[Arlino]

I reviewed the previous threads about using a 70cc in stock carb, one moderator said it can be done with higher jets like 84-90 main jet and raising the needle 1-2 clips with stage 1 and Next R pipe. But it will be better if u use a bigger carb as what lennox said with an expansion chamber pipe. I googled it ( search 14mm teiki stock carb in 70cc cylinder ) recomendation came from provo moderator.

[PreBug308]

You can run the stock carb with bigger jets. I'd get a larger carb though, you'll get a higher top speed and run safer.

[Arlino]

Vewato what kind of pipe you have.

[vewato]

I have a technigas Next R Chrome pipe. Good news though...i just ordered an Arreche 19mm carb with an unifilter airbox too. Does anyone know what size jets would be wise to use?...i had a day off from college today and i did some testing and i took the beast down a hill and i think i was going around 45 or so and soon after i got home I ordered the 19mm. i was thinking to myself that the amount of fuel/oil/air needed to push that cylinder fast enough, probably can't get through that little 14 mm carb fast enough...and after looking at the recent posts it enforced my intuition. Man i would think with this set up i should get a lot more than 45 out of it! Because i have seen a huge increase in low end torque, i can actually ride wheelies without leaning back a bunch. Also i was thinking about switching to full synthetic oil, what changes would i have to make other than the obvious of draining and refilling oil? how would i know its running rich enough? Anyways thanks again for all the input, a huge help!!

[xraydino]

Your gonna need a pretty big jet to run with that uni filter. Not sure of the largest jet that the kit come with but, be careful. Do a few plug reads to see how you're running. You can allways use the stock box if your hot.

[vewato]

right on. i was afraid of that...i'll be carefull. i wish i knew for sure...

[pinkymingeo]

All the guys with Arreches and open filters seem to be using a 105.

[xraydino]

I tried a 105 with a few holes in my stock airbox. Couldn't really tell if it ran any faster than my stock box with an 80. But, one thing for sure that 105 sure did love fuel. I was probably getting about 35-40 miles to a tank of gas.

[Frank the Tank]

does a scooter run better with an airfilter rather than an airbox?
and how much louder are the filters?

[pinkymingeo]

When I first started tuning this thing I had a couple of long chats with Skull. Nobody knew more about Zumas. He told me absolutely that an open filter won't help with a midrange cylinder/19mm. Then I talked with the guys down the street. They wouldn't really take a stand. For a long time I've been asking for somebody with a tach to do a comparison, and report any rpm difference. No responses. I don't believe it makes any difference at the T6/19mm level. If you must go open filter, a pod/unifilter is the worst way. Very loud, and vulnerable to weather. You can get a race foam filter cut to fit the stock box. Quiet, weatherproof, and the same, or less restriction as a KandN.