Fuel System: Gas (Petrol) tanks, Carburators
7 posts • Page 1 of 1
Bike is 1964 CB77Superhawk, this problem has always been lurking in the background but seems to got worse.
If I rev the engine it takes several seconds (like 7 or 8) to return to tickover. I have checked the throttle cables, looking into the intakes I can see that both throttle slides have snapped back to the tickover position.
I did a compression test today, the left cylinder is definitely a little low (like 15 psi) compared to the right. Might this cause the problem?
The lower compression is unlikely to be the problem, if you definitely have some slack in the throttle cables, then an air leak in the inlet manifold or carb joints is the most probable cause. When the bike is idling try spraying some WD40 or similar around any joints to see if there is any reaction.
Thanks for the input, after some further investigation this turned out to be a side effect of the ignition timing being off.
I think because the ignition timing was off (retarded) I had tweaked the carb setting to get it to tick-over at a reasonable speed.
After re-timing the ignition I needed to make further adjustments to the carb setting, when that was done everything is MUCH better!
"Its hardly ever the carburetor its almost always the ignition" ~ my Dad, bless him, c1954
And you guys claim to speak English! ;-)
As for the reluctance to 'tick over', I have experienced this myself. Well, my bike has. In one case it was a sticky throttle cable and in another the ignition timing was off. My suggestion is to check everything in the fuel and ignition systems, essentially doing a major tune-up.
Meanwhile, I think I'll put on my toque and running shoes, pack a toof from the LCBO and paddle my 15' Prospector to Joe Batt's Arm, avoiding the muskeg along the way.