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Does not know Everything !
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Discussion Starter · #1 ·
Now that the alarm is removed and wiring bypassed i have tried staring it.

With the engine turning over normally it spins once or twice really weakly and then stops turning all together.

With the plug removed it spins happily with no sound of knackered bearings at all !! w00t

Looks like it just needs bumping a few times.

Oh, and a new battery, this one doesn't hold enough charge after all these months unused.
 

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Does not know Everything !
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There is such a thing as too much compression ?

Its got a custom machined head........
 

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Discussion Starter · #6 ·
I only want it for work.....urgh.

Im gonna end up running methanol.......
 

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2 Strokes And I'm Happy
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Does not know Everything !
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Once i have checked it out to see if it is too high, and then worked out how to lower it, i might just do that.

Just for the record, how much is too much ?
 

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http://www.motorcycle.com/mo/mcrob/rt-fuel2.html

Compression Ratio

CR = ( V1 + V2 ) / V2
CR is compression ratio
V1 is cylinder volume at exhaust closing
V2 is combustion chamber volume

Its a bit of a black art as ut depends on how well the expansion chamber works. Best working out corrected and uncorrected ratios and comparing them to stock bikes.
 

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Discussion Starter · #11 ·
I was thinking more of a pressure reading i should be looking for, although the link made good reading, thanks.
 

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I'd expect anything over 200 psi to be too much. Anything below 100psi to be not enough. Quick bit o maths says it SHOULD be at around 180psi (ish), but in reality being a bigbore kit it could read anywhere between 140psi (as a working minimum) and 200psi.

If you can find figure for stock Mito125, and add 28% I'd expect that'd work as a ballpark figure to aim at.
 

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Discussion Starter · #13 ·
The way to alter the reading is to play with the squish ?
 

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Take yer pick - squish or stroke - squish is easiest. Stroke requires changing conrod - not exactly "doable". Can be done via varying pistons... but "meh" is about all I can say to that - s'not like u have a vast array of choices in front of you really.
 

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Discussion Starter · #15 ·
Squish it is.
 

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2 Strokes And I'm Happy
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yeah altering the squish is the best way to do it.
 

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Discussion Starter · #17 ·
Cool, thanks.
 

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125cc Sportsbikes Supporter
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Cool, thanks.
there should be picture with your 160cc kit of the angle of the head.
look at the polini website, maybe they have it there.
for the clearence between your head and piston use a piece of tin solder put it through the plug hole to the side if the cilinder and tik it over once so the piston crushes the solder against the head.
this should not be thiner then 0.9mm
 
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