1980 CB750 Custom - Running Hot

Posted by tketter on Jan 13, 2013; 4:57pm
URL: http://vintage-and-classic-hondas.81.s1.nabble.com/1980-CB750-Custom-Running-Hot-tp4035245.html

I've recently acquired this bike.  I've removed the airbox, replace with velocity stacks, cleaned the carbs and installed the Dyno Stage 3 Jet.  I've also installed a 4 to 1 exhaust.  

I went with the suggested (no airbox, 4 into 1 exhaust) jetting that was suggested in the instructions.

Notch (3) on the needle, (75) main jet..  I think...

The bike seems to run good.  Starts, idles good!  Very responsive throttle..  

I have not synced the carbs..  only bench sync! (Visually)

Here's what it does....

After about 15 mins of riding the bike shuts off..  I think this is a vapor lock due the gas cap.  I had to replace the gas cap and I'm not sure it's venting properly.  This isn't the biggest issue..  

What concerns me is that there is a lot of smoke coming off the engine and out of the air vents (one has a filter, and the other is a hose near the starter).  

I checked the oil level.. spot on..  looks good!

The bike seems to be running HOT!

I'm thinking it's running too rich..  I might need to adjust the needle height.

Any thoughts...??

I'm new to this so thank you for all your input.  

Best!