Topic: 1986 honda trx 350 four trax problem

[WFO]

Ok get this i bought this beast ran great, anyways i cleaned her up fixed all the loose and broken stuff changed diffential oils ect ect ect i was going to fix the stuck choke cable which i did it hadn't been lubed in years was my guess. Anyways i had to remove it from the carb end to do so and thought since i had it apart in there i would run so carb cleaner through it since the PO seemed to do nothing other than changed the oil when he was suppose to couldn't hurt right  . Even since then the bike runs like #$%* on the top end so i took the carbs apart figuring i had loosened something up during the cleaning and plugged a jet or something. I put her all back together and she starts right up (but still runs like #$%*)


Your thoughts on my conumdrum...

[mattcb350f]

How'd I miss this post WFO???..... You've probably already got it fixed by now 

Oh well, if not........

Your carb likely has the plunger on the right hand side which is the choke valve correct?

The choke cables are notorious on these old quads for hanging up, and the return spring on the choke plunger is weak at best. Even binding of the cable in and around the handle bar can cause the plunger to open  You need a free cable for starters to fix this problem, then....

With a 14mm wrench, you can remove this plunger without taking the carb off. Then plunger and bore tend to get gummed up and corroded over time which holds the pluger up and enrichens the mixure (crappy running symtom).

Use some fine sand paper or scotchbrite pads to clean both the bore of the plunger and the plunger itself untill it moves nicely. Also check that the rubber gasket is in place at the bottom of the plunger (very important as well).

With a new/free cable and a clean choke plunger this should solve the problem.....if the problem is indeed the choke system.

I've had to fix this issue on my 86 TRX250 once or twice, and again on another 400 Foreman. I suspect this is you problem.

Another issue is that these 'big' singles seem to like a lot of back pressure in the exhaust to run at high rpm's. If the muffler is missing, or cleaned out it will make the bike too rich at seemingly high rpms. Keep in mind, these engines don't like to rev much.

 Matt.

[WFO]

How'd I miss this post WFO???..... You've probably already got it fixed by now 

Oh well, if not........

Your carb likely has the plunger on the right hand side which is the choke valve correct?

The choke cables are notorious on these old quads for hanging up, and the return spring on the choke plunger is weak at best. Even binding of the cable in and around the handle bar can cause the plunger to open  You need a free cable for starters to fix this problem, then....

With a 14mm wrench, you can remove this plunger without taking the carb off. Then plunger and bore tend to get gummed up and corroded over time which holds the pluger up and enrichens the mixure (crappy running symtom).

Use some fine sand paper or scotchbrite pads to clean both the bore of the plunger and the plunger itself untill it moves nicely. Also check that the rubber gasket is in place at the bottom of the plunger (very important as well).

With a new/free cable and a clean choke plunger this should solve the problem.....if the problem is indeed the choke system.

I've had to fix this issue on my 86 TRX250 once or twice, and again on another 400 Foreman. I suspect this is you problem.

Another issue is that these 'big' singles seem to like a lot of back pressure in the exhaust to run at high rpm's. If the muffler is missing, or cleaned out it will make the bike too rich at seemingly high rpms. Keep in mind, these engines don't like to rev much.

 Matt.

Thanks for the tips i went through ( everything ) on this quad it really is in great shape for how old it is and it's mainly for my dad to help him get around our cabin up in steamboat but i did finally find out what was wrong ( bad spark plug) it showed spark but i guess it wasn't enough but she runs like a striped assed ape now and it should for years to come.


I had to replace that o-ring on the choke plunger ( weird choke ) i never seen one like that before i also re jetted it for high altitude my dad called me yesterday to say it was running great and he want's to put a hitch on it lol.

[mattcb350f]

...i did finally find out what was wrong ( bad spark plug) it showed spark but i guess it wasn't enough but she runs like a striped assed ape now and it should for years to come.

Cool. glad to hear it runs well now. For some reason, I go through at least two plugs a year. One day it won't start or just backfires.......then I know the plug is gone again  Change it, and I'm good for another 6 months.

Does the 350 not have a hitch on the rear swing arm? Maybe it's gone.

I'll have to post some pics of mine, which I believe is the same as what should be on your dad's.

 Matt.

[WFO]

...i did finally find out what was wrong ( bad spark plug) it showed spark but i guess it wasn't enough but she runs like a striped assed ape now and it should for years to come.

Cool. glad to hear it runs well now. For some reason, I go through at least two plugs a year. One day it won't start or just backfires.......then I know the plug is gone again  Change it, and I'm good for another 6 months.

Does the 350 not have a hitch on the rear swing arm? Maybe it's gone.

I'll have to post some pics of mine, which I believe is the same as what should be on your dad's.

 Matt.

Its has a mount ( but no hitch) but i found one on ebay.

[mattcb350f]

Its has a mount ( but no hitch) but i found one on ebay.

Ok, nevermind the pics then. Just make sure when you bolt it on that you use some loctite. I broke mine off when some bolts came loose and now it's welded on.

Should be two bolts on top and two on the bottom.

 Matt.