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Discussion Starter · #1 ·
I've tried the search function to no avail...

Here's the Problem:
Bike won't rev over 5500-6000 RPM while riding it (any gear).

Here's what i've looked at/tried:
Engine will rev to red line while stationary
timing on both cylinders is good at idle
timing advance is the 12.5° at 3400 rpm and above.
adjusted the timing chain tensioner
tappets are adjusted
points and condeser are brand new
i've cleaned the carbs

like to hear peoples thoughts...

Thanks,
Alex
 

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Sensei
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What are your compression PSI readings?.....Run and produce usable power are two separate entities......
 

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Discussion Starter · #3 ·
66Sprint said:
What are your compression PSI readings?.....Run and produce usable power are two separate entities......
compression on the warm engine is between 171 and 180 for both cylinders.
It produces a good amount of usable power upto that 6000 rpm area.
 

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Sensei
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Running out at top end is often carb related...... Are you getting good fuel flow from the petcock....Floats set properly?.......What size jets are you running?...Secondary main could be small or partially plugged.....
 

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Discussion Starter · #5 ·
66Sprint said:
Running out at top end is often carb related...... Are you getting good fuel flow from the petcock....Floats set properly?.......What size jets are you running?...Secondary main could be small or partially plugged.....
we were tossing some ideas around here at work. We are pretty sure it's a carb issue.
I set the floats properly (18.5mm from the bowl/carb interface surface).

One thing that I noticed when tuning the idle speed mixture was that it didn't have much affect on the RPM's at idle (manual says adjust it in until you reach max rpms). So we are thinking that the idle circuit might be a bit gumed up.

before I pull the carb off again i'll try running it without the in-line fuel filters I installed.
 

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Discussion Starter · #6 ·
Figured out what was going on.
Sunday night I drove the bike around for the first time. At first it was running great, but on the short trip back it was progressively getting worse.
Yesterday after work started trouble shooting. Both cylinders were getting spark (checked with a timing light).
Disabled the ignition for each cylinder seperatly. It would run on the right cylinder but not on the left (not even a sputter).
Pulled the plugs to make sure the gaps and conditions were good. The left plug (the non running cylinder) was a bit fouled and dry, meaning it wasn't getting fuel.

Let it run a little bit to feel the heat build up in the exhaust headers... Right cylinder getting nice and warm, Left cylinder not doing too much.

Pulled the carbs off to inspect.
Checked the diaphragms, they looked almost brand new from the PO.
Pulled the float bowls off (I had them off to clean the jets on Sunday)... Ah Ha!

Some how the primary jet had backed out and fell into the bowl.

Re-assembled, made a few adjustments and she runs amazingly well. Nice strong pull from a stop and goes all the way to redline.
 
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