Re: Tuning problem on 1980 CB750F brat racer

Posted by robs750 on Jun 28, 2012; 3:06pm
URL: http://vintage-and-classic-hondas.81.s1.nabble.com/Tuning-problem-on-1980-CB750F-brat-racer-tp4023368p4023732.html

[QUOTE]I am getting strong power from cyl 1, reasonable power from cyl2 poor power from 3 & 4 at idle the cyl 1& 2 exhaust temp near the head is about 200deg C and on 3 it is about 60 deg C and 4 is about 80 deg C. [QUOTE]

Sounds like no spark at #3,4 or no fuel.
The easiest thing to do first is to verify spark at the plugs.If there is no spark,I would think the plugs would be wet from fuel.

If there is spark,I would check the compression.If the compression is good,then I would be looking at the carbs.
If the compression is low/uneven,check the valve clearance.