RM 125 Compression

[dajogejr]

100% it will. The only thing similar is they're both two strokes. That's it.
I would talk to local racers to see who does work for them.
Squish, squish angle, dome stepping, cc's all have a BIG part in how an engine runs and how it needs to be tuned.

[Suzuki Ridez]

Originally Posted by dajogejr

100% it will. The only thing similar is they're both two strokes. That's it.
I would talk to local racers to see who does work for them.
Squish, squish angle, dome stepping, cc's all have a BIG part in how an engine runs and how it needs to be tuned.

ah, problem. ive never been to a local mx track. ive only ever ridden in one place in my entire biking life.

i noticed when i took off my top end there was carbon deposits ONLY where the pitting was and ONLY on the side of the piston where it fired below the pits.

what could this mean?

[dajogejr]

Post up a pic of the top of the piston and of the head itself.

[Suzuki Ridez]

Originally Posted by dajogejr

Post up a pic of the top of the piston and of the head itself.

as you can see the pitting is fairly bad, i wiped away the deposits

heres a link

top of piston

cylinder head

[Suzuki Ridez]

does anyone know what the stock compression ratio of an rm 125 would be?

[Suzuki Ridez]

tis a pity no one knows much about the RM's

anyway im gunna strap my head in a lathe and cut away the pits. then im gunna mill the the head to compensate for the loss.

[Suzuki Ridez]

does this seem right to anyone?

i tried to calculate the comp ratio of my bike and came up with this


Swept Volume - Volume of cylinder with piston at exhaust port opening

to TDC. = 55.5mm

3.142 * 2.7 * 2.7 *5.55 = 127 / 3 = 42.37 cc's

Head volume 8cc

42.37 + 8 / 8 = 6.29

CR = 6.29:1

[zillaguy89]

sounds in the neighborhood to me for an uncorrected ratio

[Suzuki Ridez]

so how would one find the corrected ratio?