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The Superhawk from hell...

Posted: Sun Mar 25, 2012 6:19 pm
by Jlovvorn
Moving my saga here, so everything is in one place.

For those that have been watching, and those that have not, I have a barn find 64 CB77 that I have been restoring since December. Things have been challenging to say the least.

She looks good.

The bike starts and runs great. I have clean carbs, new battery, stock jets, needle positions, airboxes - the works.

Been through too many problem to count, the latest being an entire timing saga.

I now have the timing right, but here is the problem, and its persistent.

No matter what I do, when the bike gets good and hot (like 40 mins plus of riding), it starts moving around at idle - up to 2500, down to 600, back to the 1200 initial setting, then 1800 for a while, then it goes way down and stalls.

I ride along thinking I have fixed the problem, and as soon as I pass the 30 to 40 min mark, everything goes crazy.

When this starts, I open the fuel cap and make sure my lines look good. It's not delivery. Tank is clean, petcock is clean, lines are clean. If you pull the bowls when it starts, they are full.

My next step will be to swap the carbs with two others I have. Ordered new kits for them so there will be no common parts with the current carbs.

The obvious answer is an air leak.

But if its an airleak, wouldnt it seal up when the bike warms up?

In any event, thanks to everyone that has helped so far.

But the problem continues.....

Posted: Sun Mar 25, 2012 6:53 pm
by bbap
Still sounds like an air leak. Crank seals possibly?

Posted: Sun Mar 25, 2012 7:12 pm
by Jlovvorn
I will add that to the list.

At this point, I will entertain any ideas.

Where is the crank seal located?

Posted: Sun Mar 25, 2012 11:47 pm
by Hotshoe
Add carb top cap gaskets if they aren't on your list already.

Posted: Mon Mar 26, 2012 7:13 am
by Jlovvorn
Thanks. Brand new. Same effect with old ones, and new ones.

Also new o rings on the flanges.

And I have sprayed WD40 while running, both cold and hot, all around the intakes - no effect.

Posted: Mon Mar 26, 2012 7:50 am
by Hahnda
Check to see if your carbs are in synch. The cables pull the slides up at the same time. Worth a look.

Posted: Mon Mar 26, 2012 8:02 am
by Jlovvorn
The slides are in synch. Tortured myself for hours with it.

Whether they are balanced with the mix screws is a harder answer.