apeik Posted November 8, 2013 Author Report Share Posted November 8, 2013 I've been losing sleep over this for months trying to figure out what could be causing it. Tried so many different approaches. Throwing in all new impeller, seals, bearing, high flow. Had someone go over port hights with me a while back, its not much different than cast, except wider ports in areas. The only thing different than my old setup, is crank cylinders, and pd coolhead, pipes and carbs, but it was overheating before the carbs and pipes. Quote Link to comment Share on other sites More sharing options...
apeik Posted November 8, 2013 Author Report Share Posted November 8, 2013 Next question, I used to run a noss coolhead which worked great, do the pro design ones not cool the water jackets, or direct water into them? Was about to just get another moss to rule it out, if the pd ones don't perform as well Quote Link to comment Share on other sites More sharing options...
KaN Powersports Posted November 8, 2013 Report Share Posted November 8, 2013 Check you crank phasing too. Make sure both cyls are 180 +/- no more than 2-3 degrees. Do you have an infrared thermometer? Check both pipes close to the flange and see if one cylinder is way hotter than the other. FYI those 'funny' domes are that way because the builder either couldn't turn a radius on his lathe, or they complimented a custom cylinder set up- bathtub domes support a different port lay out (sled engines-for example). If your squish band width ratio is in fact too big (I kind of doubt it is) You can try retarding the timing a bit more so the piston has time to let the trapped fuel loose and provide the time for flamefront to 'get to it'. It'll be at the expense of power, but you'll know if it is the domes (squish/bore ratio) fault... I like the checking for collapsed baffle or plugged pipe suggestion above. I've had my butt kicked in a carb before when all along it was a carboned up chamber. Quote Link to comment Share on other sites More sharing options...
apeik Posted November 8, 2013 Author Report Share Posted November 8, 2013 Had the pipes off yesterday, silencers/stingers were clear, can see through headpipes, but just some oil residue in there from probably a few jet sizes to rich. I was praying something was wrong with my impeller the other day when i pulled it apart...then it would all makes sense. I just hope before long i figure it out, because there's no point in even taking it to the desert anymore, it's like a 7k paperweight...a fast overheating paperweight . i wish i didnt have everything in this, and i had extra cylinders/crank/head to test with, it's the only thing i cant just rule out, even though the cylinders just came back from millennium and all. Quote Link to comment Share on other sites More sharing options...
KaN Powersports Posted November 8, 2013 Report Share Posted November 8, 2013 Call me tomorrow (801) 686-4556 Nate. I'm tired but have a few more questions.... Quote Link to comment Share on other sites More sharing options...
apeik Posted November 8, 2013 Author Report Share Posted November 8, 2013 Thanks Nate, ill give you a call tomorrow. And thanks everyone so far for the help, means alot, nice having somewhere to turn. If you have a fucked 250r you're pretty much screwed lol. Quote Link to comment Share on other sites More sharing options...
KaN Powersports Posted November 9, 2013 Report Share Posted November 9, 2013 ^^^^LOL Quote Link to comment Share on other sites More sharing options...
apeik Posted November 9, 2013 Author Report Share Posted November 9, 2013 just figured id update, thanks to Nate, at kan powersports... he killed a few hours out of his day to walk me through checking crank phase and it appears it's as much at 7 degree's out, causing deto on one side. ill keep this updated since it's such a weird problem. Quote Link to comment Share on other sites More sharing options...
KaN Powersports Posted November 9, 2013 Report Share Posted November 9, 2013 Glad to help-hope it's solved for you Quote Link to comment Share on other sites More sharing options...
lil Doobie420 Posted November 9, 2013 Report Share Posted November 9, 2013 nice.. Quote Link to comment Share on other sites More sharing options...
quadgod211 Posted November 9, 2013 Report Share Posted November 9, 2013 ive never checked crank phase is this just a random thing happening or is it something everyone should know about there motor like squish and compression??? Quote Link to comment Share on other sites More sharing options...
apeik Posted November 9, 2013 Author Report Share Posted November 9, 2013 probably the guy that had it before me on alky, dropping the clutch about a billion times...course i was told the crank was tight. And i was also told it was just welded and true'd 2 rides ago, and that the whole package was ready to run. lesson learned, the whole package i bought turned out to be a beat up pos, and i shoulda bought new, i woulda saved money, and had new stuff. without problems from the get go. Quote Link to comment Share on other sites More sharing options...
KaN Powersports Posted November 9, 2013 Report Share Posted November 9, 2013 The phasing should be checked on every crank install. Welded one of, course shouldn't need to be worried about, but I see plenty that are welded out of phase. The phasing is a real common problem on the bigger bore, or higher compression engines-(hence the reason for welding them up in the first place). I had a Skidoo 800 in here last year that had a shaved head, a dome piston in place of the original flat top, and had about 195 psi of cranking compression. It detonated, and the PTO side spun a complete 180 and was inline with the Mag side (by 3 degrees). The customer rode it out like this-hahaha..... I just hope we were able to help with Apeik's problem-sounds like he has fought this for quite some time Quote Link to comment Share on other sites More sharing options...
possum Posted November 10, 2013 Report Share Posted November 10, 2013 Nice KaN your the man. And another story of a ready to "run" used motor turns out its trash. Who woulda thought. Quote Link to comment Share on other sites More sharing options...
RagunCajun Posted November 10, 2013 Report Share Posted November 10, 2013 is there a procedure to check? Id like to book mark it for future tear downs. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.