So it has been over 2 years since I started my project motorcycle. It’s a 71 honda cl350. I bought it in boxes and slowly put it together with the help of a friend over the last 2 years.
Last weekend I actually got to go out and ride the damn thing! I have to admit it was a little frightening, because it’s been 2.5 years since I last rode a bike, and even that was only for a 3 day licensing course. All in all it rode well, and most of the problems were with my shifting ability, or my riding ability.
The one issue that I did have was the bike continues to rev high after putting the clutch in. The only way I can get the revs to come down (at a stop sign for instance) is to downshift and brake all the way down into 1st gear. If I get it down to 1-2k then it will generally stay there.
I have checked for air leaks between the carb and the engine. None found. My next guess is that the two carbs are somewhat significantly off. I have heard that can cause the carbs to ‘fight’ each other on the way down. The 2 exhaust pipes differ in both strength and temperature.
So in conclusion: don’t worry, i’ll update this post with pictures in a bit, and has anyone out there on the internets had a similar problem with a similar bike? I know alot of you have from googling, but I’ve found a lot of dead ends, and seemingly bad advice. I’d love to hear it first hand from anyone that had been afflicted by it! Let me know.
I found your site on technorati and read a few of your other posts. Keep up the good work. I just added your RSS feed to my Google News Reader. Looking forward to reading more from you down the road!
Make sure it’s not the throttle or choke (including cable). You’d be surprised how much weirdness can be tracked to that.
Ryan’s right – first check the throttle cables. Most bikes have two – one ‘push’ and one ‘pull’ – when you twist the throttle and let go, it should ‘snap’ back to idle position. If it doesn’t, you’ve got a safety issue. Next on the list is (like you said) the carb sync’s. Depending on your resources, you can either “eyeball” them or use a sync gauge. Eyeballing will get you very close, but you have to take the carbs out and look down the throats to make sure the butterflies are set the same. Next on the list would be the IAC or Idle Air Control screws. They’re tiny flat-blade screws on the side of the carbs – they’ve gotta be set pretty close to the same or you’ll have problems. Take a look at the spark-plugs to see how each cylinder is burning – that’ll tell you alot too. Good luck – that’s an awesome bike (was my first)!
Dale made some good comments. If you have not figured it out yet the revving and exhaust issues sound like two different problems. The idle if its not throttle cable issue its carb related. air or fuel mix problem. That might cause one cylinder to misfire and cause temp problems, maybe check spark or timing. Keep troubleshooting! Good luck…