I recently bought a 1982 Honda CS250 four-stroke road bike. The bike starts good and runs good except.... when in a higher gear (3-5) and you let off the throttle to coast, and then open the throttle up again, it has a real bad hesitation. If you leave it 3/4 choked, it eliminates the problem. That would lead me to believe that it is running way to lean and choking it richens the mixture and makes it run better, but I searched for a mixture adjustment screw and cant find one.... the only adjustment screw i could find on the carb is up by the intake manifold and it faces downward. I turned it in (to the right) about a turn and a half and it helped a little bit, but im assuming that screw is like any other carb adjustment screw and turning it in would make it leaner.. so it doesnt make sense. Does anyone have any ideas? Also what does that screw adjust? Also sometimes when i start it, it make almost a whistling sound that i think is coming from the exhaust? Is this related?
2007-08-31 14:54:13 · 8 answers · asked by Anonymous in Cars & Transportation ➔ Motorcycles
The air filter is new. I am running premium gas in it. The plugs and wires are good. Im assuming that the jets are not adjustable on this carb. It is a stock carb. Could the jets just be gummed up? I dumped some carb cleaner in the tank and rode out almost a whole tank worth with it in there, with no improvement.
2007-08-31 14:57:23 · update #1
You should have bought a drum set. You're wasting your talents you know. Wasting.
2007-09-01 14:19:28 · answer #1 · answered by pancakes & hyrup 6 · 0⤊ 1⤋
The best stuff I have found is Yamaha carb cleaner! I have used this stuff on bikes that have set for ten years ! I used to tear them down to clean them but not any more. This is how you do it. First take off the gas tank, Then drain the carbs using the drain screw under each carb. Then close the drain screws after carbs are drained. Then take a sixty cc syringe if you can find one, or use something similar. Fill the syringe with the carb cleaner, and the stick it into the fuel line that was disconnected from the fuel tanks. Start pushing the cleaner into the fuel line until you get it running out of the over flow line from each carburetor, then stop and let sit for twenty four hours.Then drain the cleaner out from the drain screws, re tighten them and replace the fuel tank. Be sure to put some in line filters on when ever you are done. If the carbs seem to still not be right, repeat process, and I guarantee you this will do the trick. Do not waste your time with that **** that you put in the tank, it may work for some but if the bike has been sitting long enough to turn the fuel,it won't work. So go to your local Yamaha shop and get some, I have been using it for years and it works !
2016-05-18 02:50:10 · answer #2 · answered by ? 3 · 0⤊ 0⤋
You could have a blocked exhaust system. With a bike as old as yours, the internal parts of the muffler can rust and come loose blocking flow. The symptoms are that the bike will start and idle nicely because the exhaust flow is little and isn't affected by the restriction. At high load and high rpm the engine misses since the higher exhaust output can't escape.
You can test this theory by removing the muffler or even the entire exhaust pipe and going on a short ride.
2007-08-31 15:40:24 · answer #3 · answered by Deckard2020 5 · 0⤊ 0⤋
If you think the carb is to lean, try raising the needle (on the throttle slide) one position - move the clip down.
The screw you're talking about is the mixture screw.
But it only affects the idle mixture - after 1/4 turn of the throttle, it has no effect.
Whistling is usually from air rushing past an opening.
Check for cracks in the exhaust, loose muffler joint (I don't know if your model has pipes that separate), or leaking header pipe (exhaust to cylinder head).
2007-09-01 08:23:08 · answer #4 · answered by guardrailjim 7 · 0⤊ 0⤋
Hi I'M NOT sure about your exact carb but . here is some things that I have found on others including honda's:
some have an ajustment screw that will stop your jet/throttle valve from going all the way closed.
at the same time they may have an ajustment at the top of the throttle valve slide that looks like the cable adjuster on your brake.
if you can get your hands on a haynes manual for your bike it may help.
hope this helps.
2007-08-31 15:39:50 · answer #5 · answered by McGiver 1 · 1⤊ 0⤋
Istead of adjusting it, I would just try to clean it out first. If you have to run the choke partly on that means your not getting enough fuel. It could be as simple as cleaning the gunk out of the carb to let more fuel through. If its clean and it still dont run rite, you might be able to get it by adjusting it, but your carb is probably wore out, Those adjustments are set to make the engine run at its best, if it dont there is something wrong, adjusters dont move themselves. A rebuild kit is cheap and easy to install.
2007-09-02 06:21:31 · answer #6 · answered by Rottonwieller 3 · 0⤊ 1⤋
I think your right about it running lean, I think it may be your pulling in air some where between carb and engine. I would carefully check rubber mounts for cracks and splits and make sure any retaining clips/springs etc are fitted properly.
2007-08-31 23:52:11 · answer #7 · answered by motomarco9999 2 · 1⤊ 0⤋
http://faq.ninja250.org/wiki/How_do_I_work_on_the_carbs%3F
everything you need to know about 4stroke carbs.
not the fastest way to get your answer, but it is the fastest way not to forget.
2007-08-31 18:01:31 · answer #8 · answered by godz68impala 3 · 0⤊ 0⤋