quiestoion about a stroked engine

[dirtbikr99]

I have a 1999 cr250. (old but I love it) Currently Its stock bore 66.4 I've had a ported, and cut the head to raise the compression a little. I love the motor right now. However, I've come across and amazing deal on a stroked crank 74mm.

1. Is it possible to just put the stroked crank in (check to make sure it clears the cases of course) and put a 2mm spacer plate under the cylinder? Will this have any effect on the porting, timing or compression?

2. What would be the final displacement with a stock bore and a 74 mm crank?

Thank you in advance to whoever can answer these questions for me!

 

[elcamino12sec]

Good question, I would also like to know.

 

[dirtbikr99]

anyone?

 

[hot125mod]

stock is 72 and you now have a crank that is a 74mm stroke so it is .080 over or 2 mills on a 250 for every 080 that you go over it is about 15cc making it a 265 which is a popular number for 250s

 

[Pete Payne]

The displacement would only be 256.246cc's . Remember that on stroking the crank only half is gained. This would be somewhat equivalent to a 1mm overbore (256.887cc's)