andrewsnyder
Member
*1989 Yamaha FZR 400*
So I've had this bike apart so many times now and have done a valve job twice now. The first time was to get them in spec but once i had it running it never ran right, it always bogged from idle, extremely hard bogging. I've cleaned the carbs an infinite amount of times now. I recently took it into a shop where the mechanic checked my carbs which were fine, sync'd them. but then when he did a compression test all of the sudden Cyl#1 had next to none compression and when a leak-down test was performed it had about 95%-100%. He thought it would be my valve clearances(too small and opening too early) but when i got the bike back i took it all apart and all my clearances except for a too big clearance on 1 exhaust valve. I changed all the shims to be on the high end of specs as some were low. I also lapped or re-seated my valves with a valve grinding compound because I thought if the clearances are fine it must not be sitting right. The valves looked fine to me, no rounding, seals good, and not burnt(cracking or wear). I finally put it back together yesterday, timing is bang on. BUT, when it started up after a few seconds of trying to get it going, ITS ALL THE SAME. Gas just spits out of the intake and you can feel lots of air coming our of that Cyl, it also still has a large bog but it does seem like it has gotten a bit better, but very little, it'll still die if i give it for long enough. I am going to do another compression test tonight and if its gone I may bring it to another shop or something as I've had this for over a year now and its taken all my money, sanity and happiness away because this damn issue causing me not to be able to finish it.
Whenever I take the carbs off, i see a lot of white "mist" or "smoke?" in the intake boots, mostly for Cyl2,3,4 less in #1, which is odd because it used to be complete opposite.
Bike has Pods(weren't on when spitting gas), Muzzy Can, 110 Main Jet(way higher than stock 87.5), new intake boots.
Another thing was gas suddenly was leaking out the bottom of my carb which I have never had before, also when I take the carbs off there is a lot of gas sitting on the boots and I have no idea where it came from. It sits on the top of the boot on the outer ring. Any ideas are EXTREMELY APPRECIATED. Thank you.Thanks,
So I've had this bike apart so many times now and have done a valve job twice now. The first time was to get them in spec but once i had it running it never ran right, it always bogged from idle, extremely hard bogging. I've cleaned the carbs an infinite amount of times now. I recently took it into a shop where the mechanic checked my carbs which were fine, sync'd them. but then when he did a compression test all of the sudden Cyl#1 had next to none compression and when a leak-down test was performed it had about 95%-100%. He thought it would be my valve clearances(too small and opening too early) but when i got the bike back i took it all apart and all my clearances except for a too big clearance on 1 exhaust valve. I changed all the shims to be on the high end of specs as some were low. I also lapped or re-seated my valves with a valve grinding compound because I thought if the clearances are fine it must not be sitting right. The valves looked fine to me, no rounding, seals good, and not burnt(cracking or wear). I finally put it back together yesterday, timing is bang on. BUT, when it started up after a few seconds of trying to get it going, ITS ALL THE SAME. Gas just spits out of the intake and you can feel lots of air coming our of that Cyl, it also still has a large bog but it does seem like it has gotten a bit better, but very little, it'll still die if i give it for long enough. I am going to do another compression test tonight and if its gone I may bring it to another shop or something as I've had this for over a year now and its taken all my money, sanity and happiness away because this damn issue causing me not to be able to finish it.
Whenever I take the carbs off, i see a lot of white "mist" or "smoke?" in the intake boots, mostly for Cyl2,3,4 less in #1, which is odd because it used to be complete opposite.
Bike has Pods(weren't on when spitting gas), Muzzy Can, 110 Main Jet(way higher than stock 87.5), new intake boots.
Another thing was gas suddenly was leaking out the bottom of my carb which I have never had before, also when I take the carbs off there is a lot of gas sitting on the boots and I have no idea where it came from. It sits on the top of the boot on the outer ring. Any ideas are EXTREMELY APPRECIATED. Thank you.Thanks,
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