HondaCB650

These carbs are super sensitive to not having an air box with factory jets. They run lean as it is. My air box is intact and still has a small amount of hesitation because of an air leak in the air box. It's probably running super lean, and when you push the choke in, it leans out so much it won't r...

You can trim the accel pump rod down.

Yeah, the hesitation seems to be there some days and not there at all others. Oh well. I'm at sea level and up to 500ft, though the air box does have an odd bend at that main connection between the front section and main filter housing. Looks like someone over tightened it and the ovel 'female' end ...

I turned the idle air adjusting needles out about 2/3 over the ~2 1/8 that were set from the bench setting. Now there is no hesitation what so ever throughout the throttle range. I'm very happy with the old girl.

Just hoping it's not just masking a different problem.

My '80 CB650C is around 60 mph at 5500rpm. Around 7000rpm it's nearing 70mph. I wasn't brave enough to take the old girl past that, though it seemed to not complain at that speed.

I like cruising at 55mph, which is 5000rpm.

Nice ride! Simple effective bike, coaster brake, and nice generator set up, nice frame pump. Where have I seen this great bike before...

Fred Birchmore rode a very similar set up around the world in 1934-1935.
Enjoy!!

The bicycle is almost 10 years older then the CB650, and I have put about 8,000 miles on it the last ~4 years.

Whats funnier is, I have a Class A drivers license, I driver commercial tractor trailers for a living. I love to drive, I just like riding my bike more!

I have never heard of a torn cam chain. Scary!! Started her up yesterday morning and it was still LOUD with that clattering noise, so only let it run for a minute or so. Then went about re tightening the timing chain while turning the crank as I tightened the tensioner. All that noise is gone and I ...

Right on. I'll be doing some fine tuning today, including the timing chain.
We did do the valve adjustment with a cold engine.
The Odometer reads 47,xxx miles, is that 'higher' mileage for these motors?

For REALLY stubborn clogs on these small jet, sonic jewelry type cleaner. I chem dipped, carb cleaned and used compressed air, twice with still some passage ways clogged. I put them in the sonic cleaner for 5 minutes and found the passage ways clear and free of crud, still used carb cleaner and comp...

While I will be doing another PD50B rebuild soon, the one that I did rebuild, I reused all but one O-ring. Is ALIVE!!!!!!!!!!! I hooked it up today and had a fun time getting it all back together. With just a bench synch, premium fuel and a little hope it runs great. Took a second to come to life, b...

Brief update. The accelerator pump passage ways were VERY clogged and had to run them through the sonic 'jewelery' cleaner again, now they flow freely. Still unable to get O-ring sizes pin pointed, but have started assembling the carbs since the O-rings seem supple and able to seal. After these are ...

That place that I was told had O-rings, didn't have any of the sizes I needed. It was a place that specializes in hydraulic systems. I was careful in taking all the O-rings off, so I'll be putting them in an oil bath while Isearch a few other places in the hopes that maybe another place may have thi...

Great info! I'll try to re-use as many pieces as I can, the air cut offs are in good condition. Accel pump is shot. There is a place around here that specializes in O-rings that I will source from. After cleaning up the carbs thoroughly, no jets need replacing, even the plungers seem to be doing wel...

Also, the accelerator pump is torn so I hope these are around as well.