Hi All, I'm looking for a rebuilt kit for a 250 SR but can't find them anywhere. Is it possible to fit a regular 250 piston and replace the small end bearing with a thicker bush to compensate for the smaller gudgeon pin? Bronze bushes are common on classic 4 strokes but not seen it in 2 strokes. I can't see there would be much difference?
Cheers. Rob
KDX 250 SR Piston kit
-
- Gold Member
- Posts: 821
- Joined: 10:00 am May 29 2012
- Country:
- Location: Spring Grove, Illinois
KDX 250 SR Piston kit
I can't comment on the suitability of the piston you plan to use, but I can on your question about the bronze pin bushing.
I have put many thousands of miles on bronze bushed wrist pin 2 stroke motorcycles with never a problem. This is both road and enduro competition riding. Also had many friends with similar experience, even some scrambles, flat track, and road racing use.
I have to qualify this by saying a typical fuel/oil ratio used was 20:1, however this was straight 40 wt non-detergent oil. I sometimes used castor and synthetic oils, and no problems with these either.
Only recommendation I can make is to be generous with the oil holes. As an example, the 19 mm pin bore I am used to has 3 oil holes, approximately 3 mm size, spaced at 120 degree intervals.
I have put many thousands of miles on bronze bushed wrist pin 2 stroke motorcycles with never a problem. This is both road and enduro competition riding. Also had many friends with similar experience, even some scrambles, flat track, and road racing use.
I have to qualify this by saying a typical fuel/oil ratio used was 20:1, however this was straight 40 wt non-detergent oil. I sometimes used castor and synthetic oils, and no problems with these either.
Only recommendation I can make is to be generous with the oil holes. As an example, the 19 mm pin bore I am used to has 3 oil holes, approximately 3 mm size, spaced at 120 degree intervals.
-
- Member
- Posts: 3
- Joined: 01:26 am Jan 18 2015
- Country:
Re: KDX 250 SR Piston kit
I need help.also look for my post.. kdx250sr f1 rebuild/hard parts..