Out of sync carbs or something else?
Posted: Tue Mar 19, 2013 5:36 pm
A few weeks ago a couple cylinders developed vacuum leaks at the intake boots so I replaced them with brand new boots and cleaned the carbs while it was all taken apart. Now I've got it all back together and I can't get the carbs back in sync. Initially I didn't use the dry sync method and my sync tool showed everything pretty heavily out of wack:
And then I took the carbs off and did the dry method, my friend got me four high quality ball bearings and double checked their sizes with a micrometer. I got the carbs almost perfectly in sync that way and then I put them back on the bike and got the exact same results with my sync tool, I even went out and got vacuum restrictors for my sync tool in case that was why it was so out of wack. The engine just ate up most of my sync tool fluid and fouled the plugs
so I've given up trying to figure this out myself. Any ideas? Could be something other than a sync issue? But what?
Things to note:
- I did not replace the O-rings for the float valve needle seat
- Checked float heights and they were all within spec
- When I rev the engine it will go up fine but come down and hang at 2K rpm for a few seconds before coming down all the way (this is why I'm assuming it's a sync issue)
- Checked the temps on the pipes and they were all between 290 - 350 F (I'm running stock jets)
I would really really really rather not take this bike to a shop, I've managed to keep my car out of them and would like to do the same with my Seca
EDIT: I'm also getting a clicking sound sometimes immediately from when I start it from the top end and sometimes I'm not. I tried setting the air/fuel screws to a baseline of 2 turns out each and it seems like that made it slightly better but the sync tool still behaved the same way. And it'll also surge at idle sometimes immediately after start but sometimes it will just idle at it's regular idle rpm. I'm completely lost as to why it's running so badly.
Thanks,
John
And then I took the carbs off and did the dry method, my friend got me four high quality ball bearings and double checked their sizes with a micrometer. I got the carbs almost perfectly in sync that way and then I put them back on the bike and got the exact same results with my sync tool, I even went out and got vacuum restrictors for my sync tool in case that was why it was so out of wack. The engine just ate up most of my sync tool fluid and fouled the plugs
so I've given up trying to figure this out myself. Any ideas? Could be something other than a sync issue? But what?Things to note:
- I did not replace the O-rings for the float valve needle seat
- Checked float heights and they were all within spec
- When I rev the engine it will go up fine but come down and hang at 2K rpm for a few seconds before coming down all the way (this is why I'm assuming it's a sync issue)
- Checked the temps on the pipes and they were all between 290 - 350 F (I'm running stock jets)
I would really really really rather not take this bike to a shop, I've managed to keep my car out of them and would like to do the same with my Seca
EDIT: I'm also getting a clicking sound sometimes immediately from when I start it from the top end and sometimes I'm not. I tried setting the air/fuel screws to a baseline of 2 turns out each and it seems like that made it slightly better but the sync tool still behaved the same way. And it'll also surge at idle sometimes immediately after start but sometimes it will just idle at it's regular idle rpm. I'm completely lost as to why it's running so badly.
Thanks,
John