Cant get the old boy firing

Posted by Sampo on Feb 11, 2013; 2:07pm
URL: http://vintage-and-classic-hondas.81.s1.nabble.com/Cant-get-the-old-boy-firing-tp4036456.html

Hi all,

New to this site.

ill brake it down to you all.

Bought a Cb750 f Dohc 1982 modell september last year. The bike run perfect.
I took a part the whole bike and chopepd and sanded the frame, did all the "cosmeticts" changed bars to clip on, new paint to the rims, new speedometer, battery, ingnition, headlight, taillight, signallights and a bunch of more nice parts and details.

I but the engine back to the frame after i cleaned it and gave it new colour.

The bike is 95% ready and i tryed to fire it upp for 3 weeks ago fpr the first time.
It started after 10 second but run only on cylinder 1 and 2.

1. I checked the wiring from battery to coils and from coils to parkplugs.
I get a good decent charging. and the spark are good on all for plugs.

2. I have cleaned the carbs 7 times. Checked and rechecked all jets. floatbowls.

After have been pulling of the carb several times and putting them back the biek wont start at all.
spark 1 and 2 are wet. 3 and 4 are bone dry.

Could it be the fuel petcock on top of the carb 3 and 4? A dissembled it and put i back to gether but i am not sure if i put the spring back the right way. If it should sit on top or on the bottom??


I shall do a preassure test this week for all of the 4 cylinders and check also the timing
But it gets air and spark, fuel only to 1 and 2 cylinder. Can it be the timing or preassure in this case?

Could a carb swap solve this problem? I can order a set of Mikuni Gsxr 36mm Flatslide carbs that are in good condition for 120$ from a friends friend of mine.


I have the Keihin CV carbs with out the Stock airboc that the carbs seem to love alot.
I have rejetted the many times and now i have 35 slow, 115, 75

Tried also with the stock airbox but no luck.