only runs good after 3000 rpm question...

5

56cbr600rr

New Member
It's a cb350. Well, I got the bike back together and running. However, it idles ok, but not superb. Try to gas it to take off and it stalls. It seems to run very roughly if at all between 1500 rpm and 3000 rpm.

If I rev it slowly past this point then it seems pretty good. I can release the clutch after 3000 rpm and ride the bike.

I'm going to let a friend check my timing and point adjustments. It has new Mikuni carbs, points, and condenser.

Any ideas on what else it can be???
 
Timing would be my first guess. I would also check the carb sync and make sure the pilot jets are not clogged.
 
I agree with Crash on the causes. And once you cure the low rpm issue, youre gonna find out that it's really not running well after 3000 rpm right now. Especially when you rev that bike up through 8000 rpm.
 
Crash said:
Timing, point gap, carb sync and jetting will all cause that to.
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trying to figure the proper size jets to run (currently 140's are installed......i got 3mm over pistons....pods on the carbs and aftermarket mufflers....any ideas. once i go over 3000 i get some "breaking up" unless i throttle it hard so i know there is some adjustments that are still needed....i have synced motorcycles before but not sure on this one....where do you hook the synce tubes to? Any help on these probs would be helpful
 
No sync tubes. My bike seems to run really good now. Think it was just the timing and points. I'm running 175 Mikuni main jets. Stock motor-so you'd need larger.


renegadmonk said:
trying to figure the proper size jets to run (currently 140's are installed......i got 3mm over pistons....pods on the carbs and aftermarket mufflers....any ideas. once i go over 3000 i get some "breaking up" unless i throttle it hard so i know there is some adjustments that are still needed....i have synced motorcycles before but not sure on this one....where do you hook the synce tubes to? Any help on these probs would be helpful
Click to expand...
 
56cbr600rr said:
No sync tubes. My bike seems to run really good now. Think it was just the timing and points. I'm running 175 Mikuni main jets. Stock motor-so you'd need larger.
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Wow i must be wayyyyy underjetted. will check points also..thx
 
Are you running Mikuni carbs? If not don't go by my jet sizes. I believe Mikuni and keihin jets sizes are not equal.


renegadmonk said:
Wow i must be wayyyyy underjetted. will check points also..thx
Click to expand...
 
56cbr600rr said:
Are you running Mikuni carbs? If not don't go by my jet sizes. I believe Mikuni and keihin jets sizes are not equal.
Click to expand...

not running Mikunis...Keihins....i will recheck the torque on the head bolts to make sure head is seated on the gasket...i forgot to recheck when i got the bike back together and ran it. Also with if it were a vac leak wouldnt it do it at low RPM? it runs fine til i get out of 2nd gear and get going ..thats when you hear the "breaking up".
 
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