Over-revving Superhawk

slarsonroy · Post by **slarsonroy** » Sun Mar 29, 2009 8:00 pm

Im trying to help my friend with his 64? 305 Superhawk. The engine has been newly rebuilt by a machine shop. Motor starts right up and revs up to about 10 grand and wont settle down. Hes had 3 sets of carbs on it, same thing. What the heck is going on? Are his carbs just out of sync? Hes got two spigots under each carb manifold that have no hose on them. I had him connect them with a hose but no change. He has plenty of gas to each carb, so its not running out of fuel and both carb pistons slide easily and dont hang up. Whats the deal? Why do these carbs like to rev and stay there? I have a 450 black bomber that has the same carbs and they like to hang up there too, but they slowly come back down if I dont touch the throttle. Somebody help us out.
Scott

mike69 · Post by **mike69** » Sun Mar 29, 2009 8:04 pm

Slides 180 deg. out? The same thing happened to me with my Dream and that was the problem.

slarsonroy · Post by **slarsonroy** » Sun Mar 29, 2009 8:14 pm

How can you tell? He said he had them swapped but now has them in the correct carbs.

mike69 · Post by **mike69** » Sun Mar 29, 2009 8:21 pm

Try turning them around. They go in either way and will feel right both ways. I haven't worked on any superhawk carbs but I think they are the same.

davomoto · Post by **davomoto** » Sun Mar 29, 2009 9:18 pm

Cutout at bottom of slides nedds to face toward rear. Idle screws turned out all of the way? Slides synced, so they both raise at the same time?

davomoto

LOUD MOUSE · Post by **LOUD MOUSE** » Mon Mar 30, 2009 9:50 am

Lots of good replies to the problem. I'd like to add that the slide cut away must be at the rear and visible, air screws (ones at the middle and horizontal) turned all the way out so as to not contact the slide (could remove if ya like), Looking into the carb check that the R/L sides of the slides are "Bottomed Out" and if not check the cable adjuster screws on top of the carbs for being screwed all the way down to the carb top plate. Also the adjuster at the throttle grip should be adjusted "all the way down/to bottom. When/if all the above is like as I describe ya should be able to tune the engine for correct idle. ........................

slarsonroy wrote:Im trying to help my friend with his 64? 305 Superhawk. The engine has been newly rebuilt by a machine shop. Motor starts right up and revs up to about 10 grand and wont settle down. Hes had 3 sets of carbs on it, same thing. What the heck is going on? Are his carbs just out of sync? Hes got two spigots under each carb manifold that have no hose on them. I had him connect them with a hose but no change. He has plenty of gas to each carb, so its not running out of fuel and both carb pistons slide easily and dont hang up. Whats the deal? Why do these carbs like to rev and stay there? I have a 450 black bomber that has the same carbs and they like to hang up there too, but they slowly come back down if I dont touch the throttle. Somebody help us out.
Scott

Code: Select all

e3steve · Post by **e3steve** » Mon Mar 30, 2009 2:28 pm

I have a 450 black bomber that has the same carbs

450BB should have totally different carbs, unless one or the other has had them changed at some stage??? I s'pose anything is possible....

The slides on a CB77 can be mistakenly inserted into the wrong carbs, hence they end up the wong way wound. This makes the mixture very rich, but won't necessarily cause the motor to rev its bollox off unless, as Ed intimates, the slides are raised by either the idle screws or by the throttle cable(s) not allowing the slides to bottom out.

Follow Ed's Tunup Recipe http://www.honda305.com/superhawk/ > FAQ (left pane)> Q. How do I tune my factory stock motor on my CB72/77 or CL72/77 for optimum performance? to the letter!

PS: just a thought: did it start easily with no choke?

Honda305.com Forum

honda305.com Forum

Over-revving Superhawk

Over-revving Superhawk

carbs

OVER REVVING

Re: Over-revving Superhawk