Justintoxicated Posted December 7, 2003 Report Share Posted December 7, 2003 iin addition to the problem im having with mounting the pipes I took the head off to change the domes. These have 1 weekend of riding on them since I put on the fresh topend I dunno what wrong with this thing but im starting to hate this frickin atv. Quote Link to comment Share on other sites More sharing options...
Leadfoot350 Posted December 7, 2003 Report Share Posted December 7, 2003 I hear ya I am begging to hate mine too. Quote Link to comment Share on other sites More sharing options...
Leadfoot350 Posted December 7, 2003 Report Share Posted December 7, 2003 I hear ya I am begging to hate mine too. Does that look like coolant on top of the pistons? Is that compression equal? How did it ride? Quote Link to comment Share on other sites More sharing options...
H300F Posted December 7, 2003 Report Share Posted December 7, 2003 looks way rich from what i can tell Quote Link to comment Share on other sites More sharing options...
PassionRE Posted December 7, 2003 Report Share Posted December 7, 2003 Justin, I had a few other thoughts while out at dinner. Are you sure your float level on that rich looking cylinder is not high? Or maybe some grit on the needle & seat? Is that the side you found the grit in the jets? One other thought, did you have any trouble or issues installing that R.H. crank seal? Did you eyeball ck the trueness of the driveside of the crank after being welded? I just did a crank that was .024" out on the driveside. Being far out on runout will cause that R.H. seal to suck tranny oil out of the tranny and cause major carbon build-up like that...just a few thoughts...Jim Quote Link to comment Share on other sites More sharing options...
Screamin_Banshee Posted December 7, 2003 Report Share Posted December 7, 2003 SHHHHHHHHHHHHHHH Jim, dont tell everyone my crank was that far out If its not a carb issue Justin, check the oil level to see if its low....if so like Jim said, it may be sucking the oil out of the tranny. Let us know Quote Link to comment Share on other sites More sharing options...
National Banshee Posted December 7, 2003 Report Share Posted December 7, 2003 Were your old pistons just loose in the cylinder or did they break? I have done lots of these with broken skirts that crack the cases. Quote Link to comment Share on other sites More sharing options...
Justintoxicated Posted December 7, 2003 Author Report Share Posted December 7, 2003 Were your old pistons just loose in the cylinder or did they break? I have done lots of these with broken skirts that crack the cases. no, I just lost alot of compression so I thought it was time for a rebuild. Ill check the oil tomarrow though. Damn it sucks being sick. Quote Link to comment Share on other sites More sharing options...
SDD Posted December 7, 2003 Report Share Posted December 7, 2003 Justin you did let the bike idle for a period before you checked the compression and pulled the head. Did you rev up the bike to blow any excess fluids out? What kind of premix and ratio is in your tank currently? Jim after you ported Justin's cylinders did you spray paint the insides of the intake/transfer and exhaust ports? When I looked at Justins freshly ported cylinders it looked like these ports were painted with a grey paint. How well does this paint hold up to the gas/oil mixture flowing through the motor? If there is paint and it came off because of the gas, I think some of that carbon on top of the piston could be attributed to the paint. Any thoughts about that? Quote Link to comment Share on other sites More sharing options...
. Posted December 7, 2003 Report Share Posted December 7, 2003 Is that scoring on the cylinder wall? Quote Link to comment Share on other sites More sharing options...
frocashmoney24 Posted December 7, 2003 Report Share Posted December 7, 2003 damn, antifreeze maybe get in there? Quote Link to comment Share on other sites More sharing options...
PassionRE Posted December 7, 2003 Report Share Posted December 7, 2003 SDD, I paint the intakes and transfers on final inspection of porting to check for low spots and distortions in the porting. Its hard to see uneven surfaces in these areas because of all the light refractions on a burnished finish. Yes, the air fuel mixture will remove this paint over time just like the factory paint Yamaha sprays them with. Its really hard to tell with the pics, but I suppose that could be part of it although it appears the carbon build-up is more on one side than the other. I think he is having a problem with carb sync or a problem with one of the carbs. He has one pipe getting hotter at idle than the other. But the bike hits on both by just moving the throttle a tad. I cant help but think that is why it looks to be burning uneven......Jim Quote Link to comment Share on other sites More sharing options...
Justintoxicated Posted December 7, 2003 Author Report Share Posted December 7, 2003 Justin you did let the bike idle for a period before you checked the compression and pulled the head. Did you rev up the bike to blow any excess fluids out? What kind of premix and ratio is in your tank currently? Jim after you ported Justin's cylinders did you spray paint the insides of the intake/transfer and exhaust ports? When I looked at Justins freshly ported cylinders it looked like these ports were painted with a grey paint. How well does this paint hold up to the gas/oil mixture flowing through the motor? If there is paint and it came off because of the gas, I think some of that carbon on top of the piston could be attributed to the paint. Any thoughts about that? No I didn't rev up the bike, not for a very long period of time before I checked the compression anyways. Yes there is some scoring on the inside of the cylinder walls, I can feel the scratch with my finger nail although they are still smooth enough that I can't feel them with my fingers...My compression actualy went up from 140/1389or139 to 145 in both cylinders after the last trip. One of the domes is nearly black, that dome came off the same side with the scratches and extra carbon. There was no coolant in the cylinders. mix ratio is 36 to 1 with castor oil. The carbs were out of sync before the last trip but I feel I got them back in sync before I went out, it idled much better and still does than before. (they were off a mm or 2 before) Any ideas? To top it off now I have the flu. Quote Link to comment Share on other sites More sharing options...
. Posted December 7, 2003 Report Share Posted December 7, 2003 Obviously something scored those walls. I would bet thats where some of your loss in compression is. You might not have enough run time on them to get a real good reading though. Are those brand new orings you have on there? They look pretty shot to me, and if you look at the pic of the bad dome it looks to have been leaking coolant (on mine you could see where it was leaking coolant to the inside and you can pretty much there) The ring looks more worn in that spot. You can see the rubber breaking apart on the dome. Check this site out that was on here a little while back: http://www.mztech.fsnet.co.uk/workshop/wrk_piston.html Check out the chipped crown drowned. Yours looks to be of the same thing going on just at a very beginning stage. Check out the marks on the piston. Kind of looks what your cylinder walls look like, just at a longer stage. I'd be willing to bet that your coolant was leaking pretty good. How many hours do you have on the engine? If you rode it for a while would the coolant bubble? I'd be willing to bet that it was a coolant leak. It would explain the loss in compression from leaking into the coolant, plus through the scoring (more through to the coolant (mine was about 10 psi almost). It would explain the coating on the piston, it would explain the scores on the walls (according to that site), and it would explain why the one side of the dome is darker like that where it was leaking. I would say pull the jugs and see if you can get rid of that scoring with a hone (should be able to with how you feel the scoring), and get some new rings and reseat them doing a very thorough break in. (if you havent do a search on here, I know i've left one of how I do my break ins) I dont know how the pistons look, if their bad a new ones only like 60 bucks, get some new orings, and try it again. I've been sitting here trying to think of whats wrong with your engine man, and was concentrating on that scoring.....and took another look at the domes and it all came together. Hope its whats wrong considering that would be the least of problems to happen. Quote Link to comment Share on other sites More sharing options...
Justintoxicated Posted December 7, 2003 Author Report Share Posted December 7, 2003 double post ... Quote Link to comment Share on other sites More sharing options...
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