90cc curiosity

[TikiMan]

So Ive been playing with this 90cc kit and a 28mm OKO carb. I was wondering what is a safe rpm to rev up to? On a nice day itll hit 10k and stay around 270 degrees on my gauge. How much heat transfer does the spark plug sensor not read?

[Wheelman-111]

Greetings:

Ministroker and 51mm bore?
What jets in the 28?
275 isn't hot at all, but thin walls warp quick above 350 on Tai kits.

[TikiMan]

Well I figure I lose some heat since the sensor sits on the sparkplug. Its the taz kit 50mm. I know its not to bad on temp but what is a dangerous temp to reach? anything over 325 or so?

[Wheelman-111]

Greetings:

If it's 50mm it's not 90cc. 81cc with stock crank. 86 with ministroke 44.1.
The extra half mm of wall thickness makes the 50 a Ton safer than a 51 or 52.
Mine ran 350, no problems. Full strokers have thicker walls in their bored cases. Other stuff breaks sometimes, but the jugs are more resilient to heat..

[maddog]

Depends on your gear ratio, lower rpms eqal cooler temps.

[Wheelman-111]

Greetings:

Gear ratio lowers RPMs?! Seriously?
By that logic, Flash 6 must never exceed, what? 4500 RPM, because it's got 7.58:1 gears.
Someone with all the expertise MadDog claims to have would know that the variator, not the final drive ratio, controls engine RPM. The 50 mm bore makes good power at 8500-9000 unless you alter port timing.

[paulpauly7]

not that im sticking up for him but half his statement is true .Lower rpms do mean cooler running temps but its the cvt which determines rpm not final drive gears