on a honda 450 twin DOHC?

Question

The motor wil run grate when ideling but when you startout to go the right cyclender cuts out entell you get about 7r's then it starts up. and the bike run's grate about 90mph.Thanks

Answer 1

It is probably a jetting issue.

Answer 2

Honda 450 Twin

Answer 3

This could be a more serious condition than what you think, although I agree that it appears to be a fuel blockage problem. The danger is that you are running the right cylinder lean. I suspect that when you remove the plugs, you will see the right cylinder plug is on the white side, while the left one is probably a nice chocolate brown.
The carburetor comes off easily after you disconnect the choke linkage. Remove the float bowl being careful not to turn the carburetor: You want to see how much fuel is in the bowl. Since you don't have a float gauge, you can compare the level to that of the left carb. i suspect that it is low.
Be careful with the floats and the bowl gasket. Inspect everything for damage, especially for pinholes in the float and wear on the the needle and seat. Although it may be a main jet clog rather than the slow jet, I suspect that the float level is too low, for some reason or other. Make sure that there is nothing wrong with the rubber diaphragm for the slide: that could be your problem area too, causing it to react sluggishly. Make sure the slide moves freely in the bore.
This might be a good time for a carburetor rebuild as if anything is wrong, you wil need parts to replace and a rebuild kit includes all the good parts.
If it's just dirt in the main jet, which I doubt, make sure you get rid of all the dirt with compressed air. You might want to clean the other one while you are at it.
Be very careful as things in there bend very easily.

Answer 4

Go through the motion and check every thing.
Check the carbs. The vacuum slide might be sticking or the gasket could be leaking.
Check the points and timing.
Check the valve clearance.
Do a leak down test to see if the valves are leaking.
Check the cyl compression
Sync the carbs at idle. Without a gage, feel the exhaust pressure on the mufflers and balance them.
If you think it's the coils, remove them and switch the wires going to the points. Then reverse the spark plug wires between the L&R cyl.
It's an old bike, so you should check and adjust that stuff anyway.
It's hard to diagnose something without seeing it.

Answer 5

Hey, that's your jets clogging up. Your idle jet is clear, and your regular running jet is clogged.

Do this: Get some TECHRON at the local auto parts store, and follow the directions. This is a gasoline additive that should clear up your carb jets, but you are going to have to run it over 7k, so the fuel is running through the carb as you stated in the question.

I had the opposite problem on my 450....it wouldn't idle, but would run great at speed. Try the Techron, if that doesn't work, you'll have to remove the carb jets, and clean them out.

It's a pretty common problem, with a pretty easy fix.

Good luck!