So you are saying that your squish is .3mm? That';s really tight. With AC cylinders and 93-94 octane I would set it on ,7/,8 Then you will be on the safe side for sure.
Aloha, it seems his squish is a bit loose. .030 thousand=.75mm and .040 is 1mm. A small air leak may be causing the problem.
frank.
What's about your ignition timing? Is it standard?
Areomyst,
The Minarelli a/c single ring T6 should be 145-150 psi. Do they have a lot of MBTE or TAME mixed into your fuel there? Steve told me once that a high concentration of those additives can wreak havoc on the air-cooled cylinders. Spring and fall fuel formulations in the midwest are not exactly 2-stroke friendly, lol. Your octane is plenty high enough, that's not a problem.
scootertrog
I honestly have no idea about the fuel additives in my area. I suppose I should do a little looking into that. I'm using the double ring kit. I've never had a problem with the single ringed one.
After considering it further, the cylinder deck height and piston length should not affect the engine like this even if it was manufactured out of spec, because I've set the squish properly anyway, so I guess I can scratch that theory.
@ Big B NRG: The squish band is pretty wide on this top end, I will try and post a photo tomorrow. How do you mean 'crappy squish band'? I suppose if it's too much I can increase the size of the dome by machining it out a little? I don't want to do that though untill I get proper measurements, which I wasn't able to do this weekend. Had to do some plumbing work under the house instead!
Hmm, post a pic, makes it easier to tell, from what I'm seeing.
I'll try and get a pic to you tomorrow.
PS, do they have mental therapy for scootertuning.net addicts who have gone through three days of withdrawl?
heres what you do, and this is commen in AC yamaha/ minirelli engines. I worked on 100s of bores and easiest cheapest and safest fix is to do this.
Run 2 base gaskets, meaning, use the one that came in the kit, and keep the stock one on as well. This will give you enough clearence to prevent detonation. You wont have to run high octane gas or do an special tuning and lost power as a result. Just do that, and maybe i suggest putting your Carb needle on the richest setting to allow more fuel when you slack off after full throttle.
ALso if you dont do that, and you plann on running that bore for sometime ona stock crank, the upper rod will fail with in a few 100 miles from where. What brand of bike did you say its on?