carburetor trouble.

[mason s]

ah okay I see. yeah it's pretty smooth through the mid. I've gone up one on the pilot awhile back & stock elsewhere. maybe I'll try going one more up on the pilot & see what she does. was just having a tough time as its symptoms seem to encompass both too lean (flat spot) & too rich (stumbling/break up) but like I said I'm also overflowing the right side which could play a role. need to get that figured out then play with some jetting

 

[hooser]

Yes you need to make sure they good before trying to tune. Good luck, let me know where you end up. Gary

 

[mason s]

will do, thanks a ton. I'm out in the shop now. just cleaned everything, checked the needle & seat, floats etc.. swapping float & needles to see if leak moves to left side to help diagnose. and put a 32.5 pilot in instead of the 30 I had. I'll report back once i get her fired up!

 

[mason s]

hooser, been out in the garage trying to get it dialed. right side seems to be running awesome, as usual. but the left keeps giving me trouble. have light whitish smoke coming out of the left exhaust when revved. not a ton but never been a problem before. no matter where I set the mix screws it seems to do it but just run worse. if I put my hand behind each exhaust the left doesn't have that nice pop that the right does when I flick the throttle. can't seem to find a happy spot. think that jettings no good? or are my problems beyond the carbs?

 

[hooser]

Maybe I missed something I thought the only problem was off idle. If the problem is only the left try spray wd on the intake and check for leaks, not to sure of stock carbs but can you switch them. problem says on left side look else ware.
Also are the carbs opening at the same time check for cable stretch and match.

 

[mason s]

that was my only problem when riding yesterday. But now with the new jets others have arose. just can't seem to get it tuned. left side kind of seems lean no matter what. but I pulled the plug & it looked oil fouled... right plug looks great. I can't switch my carbs but that'd be nice. carbs are synced & seem to open simultaneously.. how do I tell if there's a leak when spraying wd?

 

[5twins]

I think you're approaching this all wrong. I've never heard of anyone tuning stock 650 carbs for mods by just changing pilots. The usual routine is increasing both mains and pilots, and leaning the needle setting to "fix" the overly rich midrange the bleed-over from those larger jets creates. It's also practically unheard of to need 3 up on the pilots.

I would suggest following the tried and proven recipe - 1 or 2 up on the pilots, 1 to 4 up on the mains, needles leaned a step. Leaning the needle is a very important step. The larger jet sizes won't work right if you don't.

I dialed in a set of '76-'77 carbs for my '78. My mods are pretty much like yours, pods and pipes. I finished at 1 up on the pilots, 4 up on the mains, needles leaned one step.

 

[mason s]

I think you're approaching this all wrong. I've never heard of anyone tuning stock 650 carbs for mods by just changing pilots. The usual routine is increasing both mains and pilots, and leaning the needle setting to "fix" the overly rich midrange the bleed-over from those larger jets creates. It's also practically unheard of to need 3 up on the pilots.

I would suggest following the tried and proven recipe - 1 or 2 up on the pilots, 1 to 4 up on the mains, needles leaned a step. Leaning the needle is a very important step. The larger jet sizes won't work right if you don't.

I dialed in a set of '76-'77 carbs for my '78. My mods are pretty much like yours, pods and pipes. I finished at 1 up on the pilots, 4 up on the mains, needles leaned one step.

thanks for the good advice 5twins. you're right I was approaching things wrong. I kept focusing on the pilot/idle instead of trying to work the whole system together. I'd go up on the mains, but the pilot circuit would act up, so I'd go back to the pilot, I should've turned my focus to the needles instead. that & getting steered in the wrong direction by friends didnt necessarily help. I'm still relatively new to this side of tuning, but want to learn everything I can, love these bikes & appreciate all the knowledge you guys share. I told myself I'd spend the day working at it until I get it. I'll let you know how everything goes!

 

[mason s]

so the gaskets on my needle jet are really worn. went to the hardware store but the closest thing seems to be too thick. put them in & it won't seat right. i got a 1.5 x 4 need to track down the 1 x 4

 

[angus67]

O ring around emulsion tube? Pm me your adress. Ill send a couple out.

 

[mason s]

O ring around emulsion tube? Pm me your adress. Ill send a couple out.

just pm'd you. thanks a ton man. couldn't find anything under 1.5 x 4mm. hoping that replacing those will solve some of my headaches...

 

[angus67]

On the way. Pay it forward

 

[gggGary]

Have you done a compression test recently?

 

[mason s]

On the way. Pay it forward

absolutely, will do. thanks again.

 

[mason s]

On the way. Pay it forward

Have you done a compression test recently?

I have not, I'm planning to when I get home later today or tomorrow. been away from home for a couple of days. but if it's any consolation my bike does kick over well, & runs on each cylinder. don't know if that really says much though.