Topic: 650 Nighthawk SOHC, I seem to have lost my paddle in this creek....

[MiGhost]

Has anyone been in the top end?   They should be fairly quiet.  It is easy to get the tensioner in wrong and is a common problem.  Listen to the 650's on utube.  Half are in wrong.

I've noticed the 650 Custom I've been riding around is much noisier than the 650 Standard I've been working on.  I tried to do the cam chain adjustment on it months back and it got much worse before I was able to get it back to its "normal" state.  I may need to go into the head myself.  I've never had one out, does the top end come apart with the engine still in the frame like the small fours?

With the stamped backbone, and the bolts instead of studs. The head should come off easily. Be very careful taking the bolts loose. They can break, or strip, and are very hard to find replacements for.

[cb650]

Can be done in frame.  clean the bolts very good before removal.  You can drop the pan first and look to see if that is your problem.  Threads here on it and on the 650 site.

[coffee_brake]

I got side-lined by the car's alternator going out on the coldest days of the year...   I never fixed a cage's charging system so I had to learn as I went.

But that's fixed now and today I picked up the new clutch cable (the old one was frozen solid after days of soaking in PB Blaster) and rode the bike.

Thankfully it shifted cleanly, no stuck clutch plates, but I can't get the revs up under load. At idle it revs all the way up to redline. But under load, it seems to be either missing or bogging down, right about 5.5 to 6k RPMs, and won't go any higher. If I keep the throttle twisted, the engine dies.

What could be wrong with the high-end miss? I was running the auxiliary fuel tank hung over the handlebar, I can't imagine it was starving for fuel.

Ideas? And thanks....
And I did the carbs by the book, with the ultrasonic cleaner. I still might have screwed something up.

[cb650]

Try removing the air filter cover. 

[coffee_brake]

Try removing the air filter cover.

Really? Is that normally done?

[cb650]

Yes.  Especially on the nitehawks.   pics on the 650 site.