green250

Any other ideas? got a new battery (good one), fully charged - but the timing is still way out as described above - i can get the left side marks to line up, but still runs rough, and when i try to line up the right side it gets even worse. as i said before, it was going all right before - the marks used to line up, now it seems to have shifted to an advanced postion by about 10mm. what about the other things i mentioned? i'm thinking it might be something else. thanks.

can someone help me out? it's an XS250, with electronic ignition - the timing seemed alright, marks lined up, went alright for a while, then later on started a bit of backfiring - pretty sure carbs are ok, and no air or exhaust leaks - checked the timing, and on the left side it seems to be way advanced(? - the double line marks for full advance are about 10mm to the right of the pointer). so i adjusted the points plate to get the left side marks to line up, but now the points plate is in a totally different position (anti-clockwise about 10mm) - then checked the right and it was out the same as the other was. tried to get that to line up, but because the points plate has now shifted, i can't get the right side to line up. sorry if this is an obvious one - i'm definately a learner. just want to know whats going on, as it was alright before - what causes the timing to go out? is it valves? cam chain? the electronic ignition components? i understand that i've probably screwed up my timing even more by altering it if there is something else going on. anyway, any help would be appreciated - i would rather TRY to fix it myself, as i don't want to spend much time or money on a motor which, at it's best, was nothing fantastic - i would rather wait and look for maybe a 400 to put in it. by the way, i read a couple of posts about putting a bigger motor in the 250 frame - what about the 650? or is that too big to fit? someone mentioned the XSV250, but there was no answer - does anyone know about that one? and i'm also wondering, what about other motors from anything as long as the dimensions are close? maybe with some alteration of the mounts? thanks.

I am wanting to fit tapered air filters (or cones) to my bike - I am still going to use the 'H-pipe' connection - but, to richen it up, someone has suggested that I change my main jet from #117.5 to #120, raise my needle height 2 positions, and then possibly raise the float level slightly. This seems to match what is said in some 'CV Carb Tuning' link which was recommended to me on this site (thanks). I just want to know if this sounds right - or would it be too much - (the needle height?) - any ideas, or specific recommendations for jet size, etc., would be much appreciated. thanks.

very good. thanks.

thanks for your help there drewpy. is the lowering of the forks for these bikes covered somewhere in the forum? do you change the fluid level, or is it done another way? sorry if these are dumb or obvious questions - but I'm learning. how do you up-size the jet? & what are the 34mm carbs? - are they the standard size for the 400? thanks again.

Hi there. Just wondering how to shorten the rear springs on an XS250 - there's a pic of a red 650 bobber on the front page of a site called yamaha650club which looks like it has some sort of ring or clamp compressing the spring(?) - or is it easier to fit a different, shorter spring if I can find a match? Also, I've seen these bikes with the tapered type air filter fitted straight onto the carby, and others which have retained the 'balance pipe'(? - H shaped tube section from carb to filter) and stuck each tapered filter on the end of it, which seems like a good idea if the balance pipe (or balance tube or whatever it is) does help performance - but does it? do I need it necessarily? if anyone has any recommendations for this type of filter on my bike, or tips on how it may alter my carb performance, negative or positive, I would appreciate any advice. And lastly, will an XS400 motor go in a 250 frame? are they the same frames? thanks.

THANKS! Very helpful indeed. I've just downloaded my manual - very happy. Both problems should be quickly sorted - and heaps of new info! - thanks again.

How do I adjust the clutch clearance on a '79 XS 250? (I've got no manual yet - are there online manuals available somewhere?) When you go to take off, it doesn't grab (bike move) till the lever's nearly all the way out - these bikes may be set up like that, I don't know - it's actually not that bad, and the bike doesn't creep with the cluth engaged & in first gear, and seems to change through the gears fairly smoothly - I'm just not sure how it is supposed to be set up. I want to replace the clutch lever too, so I may need to re-do my adjustment - that's why I want some info on that. Also, I suspect that my battery is not being re-charged - I was told that I might need a 're-wind', or that it's my regulator. Any suggestions? Is there a (relatively) easy way to check/test/diagnose this fault? And, in relation to that (power supply), when I increae my revs, should my lights brighten (fractionally) at all - showing increase of 'in-flowing' charge? As is, there is no real noticable change when revs go up - I was told that this may mean I'm not generating charge - is that right? Any help is much appreciated.