intermittent high idle

[DickyDanger]

Been working on a 85 200s and it sometimes it will just go from a nice low rpm idle to high reved idle. It will also do this sometimes after a short blip of the throttle. I noticed their isnt a fuel adjustment on the carb just the air adjustment which I turn down when it starts to rev until it calms down or stalls. The idle air screw is currently set at about two turns out from closed, it has a new plug new air filter fresh oil change and fresh gas.Where should I start?

[DohcBikes]

Check for air leaks. 200s has a fuel screw not an air screw. Also the idle screw or groove may be worn out.

[DickyDanger]

Thanks for the correction! I didnt even realize. How many turns out from closed should I normally have that set at.

[DohcBikes]

I don't have the specs handy but 2 turns out from soft seat is usually a good starting point. Out for richer, in for leaner.

[6speedthumper]

The general setting is usually between 1.5-2 turns out from seated. Anything more then 2.5 you should go up one size on the pilot jet and reset screw to stock. I'm sure someone will chime in with the actual factory setting. As for the idle, take that mixture screw out and make sure that the o-ring that goes on top of the washer is (a) in the right place; and (b) is still soft and intact.

[DohcBikes]

Another thing to check is the slide diameter to bore ratio, worn slide will have you chasing your tail. Do a couple things and post the results.

[barnett468]

Hello Dicky Danger;


How much choke does it take to start?

How much throttle?

How cold is the air temp where the bike is when starting?

How soon can you remove the choke and it will idle?

Does it start easily?



In addition the things mentioned I would also do the following.


GAS LEVEL - Check the actual gas level first by doing the following:

1. get a small 10” long piece of clear plastic tube.
2. connect it to the float bowl drain fitting.
3. hold it close to the carb with the open end even with the top of the carb.
4. open the gas valve on the tank and drain screw on the carb bowl.
5. the gas in the tube should be from even with the bottom of the main carb body to 3/16” below it. If it is outside this range, I would correct it.


Since it starts and idles well for at least a while it seems your pilot jet might be fairly close to being the correct size providing the idle mix screw is around 3/4 to 1 3/4 turns out as implied above.


AIR LEAK – Use flammable brake cleaner with the long narrow nozzle and spray gently around the intake boot etc. If the rpm increases then reduces when you stop spraying, you have an air leak.


THROTTLE CABLE – Make sure it has free play at the carb top and is not binding or getting pinched.


IGNITION ADVANCE UNIT - Make sure it is working freely, returning to the stops freely, has tension on it when it is in the static position and both springs are present and unbroken.

http://www.cmsnl.com/honda-atc200s-1984-usa_model965/partslist/E++02.html#results


CARB SPECS – See them in the free online service manual in the link below. It might take up to 6 minutes to load.

[DickyDanger]

Thanks for all the tips I will try everything suggested tonight. Off the bat it varies between 7 and 20 degrees around here but the trike is stored in a heated building around 60 degrees. Inside it starts first or second pull no problem but have to give it a little gas to keep it running at first and outside it takes about 3 or four pulls sometimes with choke sometimes with out but still need to give it a little gas to keep it running until it warms up. I will do some testing and post my results

[3wheelrider]

Check for air leaks^^^ -(It could be the large O-rings on each side of the intake man. allowing air to get sucked in). They degrade & get flattened & wont seal after time.....
Also, check the tiny clip on the needle. If the needle clip is not in place the needle will float around (up & down)- The throttle may also get stuck open (eventually) if this is the case. Be sure the clip is in place! Very important for your safety!

[yaegerb]

One of two things IMO. Either you have an air leak (spray carb cleaner around the intake while its idling to see if it dies) or your throttle slide is sticking (thoroughly clean with carb cleaner and wipe with a fiber cloth). If those don't work then I would rebuild the carb.

[DickyDanger]

One of two things IMO. Either you have an air leak (spray carb cleaner around the intake while its idling to see if it dies) or your throttle slide is sticking (thoroughly clean with carb cleaner and wipe with a fiber cloth). If those don't work then I would rebuild the carb.

I did have the carb off recently. I did NOT open it up and clean or inspect it. The boot from the air box to the carb is newer and has two brand new hose clamps holding it in place. I will take the carb off and start there and follow every one else's suggestions as well and report back. I just got my 110 running like a champ with no issues but this 200 seems to have lived a tougher life

[shortline10]

Installing a # 40 small jet makes a huge difference on how the bike idles and responds . The stock # 35 or 38 depending on the year is just to small

[DickyDanger]

its a 1985

[DickyDanger]

I sprayed the intake with carb cleaner where the intake mates with the engine and it instantly died. Im going to assume I have a vacuum leak there.

[barnett468]

I sprayed the intake with carb cleaner where the intake mates with the engine and it instantly died. Im going to assume I have a vacuum leak there.LOL. Just make sure you are not getting cleaner into the intake side of the carb. this would affect your test.

this is why i suggested using a long nozzle on the can and spraying gently. flammable brake cleaner will increase the rpm if you have a leak. see if your carb cleaner says flammable on it. they make everything out of water these days, lol.

[DickyDanger]

Im not sure if its flammable I will have to look it comes in a five gallon can and it goes into another smaller can with a trigger and tight small nozzle and is used by pressurizing the can with shop air. I sprayed it in between the carb and motor side and it died. I did the same test to my 110 that I assume has a similar issue and it died to. On the 110 I sprayed it where the carb meets with intake manifold where that tiny thin black gasket sits. The issue with my 110 isnt crazy idle but sometimes it fights to idle and will just die. It must not be flammable brake fluid because after they both died it took three or four pulls to restart each.

[barnett468]

ok, below is the orig parts fiche. you need all these parts.

http://www.cmsnl.com/honda-atc110-1983-usa_model7167/partslist/F++12.html#results


if it leaks at a paper gasket, you can seal it with black permatex gasket maker or similar.

if it leaks at the carb o ring, you can use aviation sealer if you need it to run right away.

you can typically get an o ring that will work from a honda dealer or an industrial hardware supply store. it should sit above the carb surface around .010". if the carb is overtightened, it might warp the flange. you can remove the studs and put a piece of sand paper on a flat surface like a granite counter or window and carefully rub the carb flange on it to see if it is warped. a new o ring should still seal up a carb flange that is slightly warped. if you color the carb flange with a black felt pen before sanding, it will be easier to tell when it is flat.

[DickyDanger]

Thanks for the tips. I was curious if I could use fast gasket on the 110's paper gasket as a quick fix to insure thats the issue with that machine and I should have new gaskets for the 200. I was too tired after work to stay and tinker tonight but hopefully tomorrow I will have more drive as my seat cover should be in for the 110

[barnett468]

yes that should work, but the long nozzle i keep mentioning, will determine EXACTLY where the leak is because the spray is confined to a small area when sprayed gently. there's occasionally a method to the madness, lol.

[barnett468]

you can also buy gasket paper and make gaskets.