honda idling issues

[mykwillis]

ok, so i've had this problem with various hondas through the years and i have no clue why. both early 80's big reds i have now do this. sometimes they idle high, sometimes so low they will die and sometimes idle right. my 125m is doing the same thing too.

i took the carbs apart, soaked them and made sure all the holes(in the jets) were free of obstruction using a small guitar string.

any ideas?

i also noticed on the big red that the needle has a few spots where the e-clip goes(needle on the slide). which slot is it supposed to go on?

sorry for sounding like an idiot and i feel stupid for asking so please be nice. :-D

[rdlsz24]

I chalk it up to old worn out carbs. When I have had this issue with a carb no amount of rebuilding seems to fix it. I get a new one

Rob

[mykwillis]

really? the slides seem pretty snug in the carb body. what exactly do you think wears enough to cause these kinds of problems?

[Xpress]

Someone told me that the idle screw wears an uneven groove into the side of the slide which causes erratic idle.

[bcredneck]

it might be on the slide opposite the idle from beening pressed aganst the sleeve thats where i see the most whear on the slide im looking at now

[hondamaniac]

standard setting is 3rd groove from top of needle....this is from the manual... an is only for standard setting. for high altitude use the 2nd groove from the top of needle...

[200XMichigan]

You want to make sure they are not just unobstructed but totally clean, use compressed air, or spray an aerosol carb cleaner through them. If they are not perfect the machine will know and run accordingly. Also you could check for an air leak by spraying starting fluid around the carb while the engine is running. Have you made sure your throttle cable is really well lubed so it fully returns every time.

[TurboTacoma]

Make sure you check your timing first. Get that right. Then get your rpm to 1400 rpm. Then adjust the pilot screw in til the engine tries to cut off. Then turn it out til it tries to cut off. Split the difference between the two. Then re check timing and rpm accordingly. I have found when using my wide band O2 sensor for tuning that advancing the timing leans it out. So if you adjust timing last.... And lets say it was retarded.... And you just advanced it after you got the idle mixture setting right.... You are now leaner.... And have to now make another idle mixture screw adjustment. Also raise the idle will do the same.. So check and set timing. Then rpm. Then idle mixture screw. Then recheck in that order.

.

[mykwillis]

You want to make sure they are not just unobstructed but totally clean, use compressed air, or spray an aerosol carb cleaner through them. If they are not perfect the machine will know and run accordingly. Also you could check for an air leak by spraying starting fluid around the carb while the engine is running. Have you made sure your throttle cable is really well lubed so it fully returns every time.


you and i think exactly alike. lol! yes sir, all of the above has been done. thats why i'm pulling my hair out. :-P any other ideas?

[mykwillis]

Make sure you check your timing first. Get that right. Then get your rpm to 1400 rpm. Then adjust the pilot screw in til the engine tries to cut off. Then turn it out til it tries to cut off. Split the difference between the two. Then re check timing and rpm accordingly. I have found when using my wide band O2 sensor for tuning that advancing the timing leans it out. So if you adjust timing last.... And lets say it was retarded.... And you just advanced it after you got the idle mixture setting right.... You are now leaner.... And have to now make another idle mixture screw adjustment. Also raise the idle will do the same.. So check and set timing. Then rpm. Then idle mixture screw. Then recheck in that order.

.


thanks! i will try this. whats the timing supposed to be on these things?

[TurboTacoma]

To check timing you need a battery and timing light. Then go to the left side of the engine. The cover that says cdi. Remove both philps head screws and remove cover. Then right below the jug. There is a plug with a large slot for a large flat blade screw driver. Remove it. To adujust the timing... The rotor has a trigger wheel mounted around it and is held by 2 philps head screws. Mark the wheel to the head first. This is just in case the trigger wheel moves on you and have a timing getting it to run. I usually loose the philips heads first and the light snug them done. Now start the bike. Make sure it is close to 1400rpms. Now take the timing light and point it at the plug hole you removed the plug from. There is a groove in the threaded part of tge plug hole. The letter "F" should line up with the groove in the threads of the plug hole. If not adjust it by moving the trigger wheel. Once you get it to "F" double check idle speed and adjust to 1400rpms. It is a little like chasing your tail.

[mykwillis]

had to file the slide where the ramp for the idle screw is and move the needle down one slot. idles perfect now!

[dougspcs]

Replacement carbs are available from Ebay for most Honda engines. I bought one last fall for my TRX300FW for $80..no time wasted screwing with 20 year old carb, but bolted it on and go.