TRX70 runs on "choke" only

[VABCH350X]

So I picked up a pristine 86 TRX70 today that hadn't been started in years. Owner's complaint was that the last time he tried to start it, it would run on choke only. I brought it home and performed the standard carb cleaning, disassembled and soaked everything, cleared all passages and jets.

After getting the bike running again, it runs only on choke, just like the previous owner described. I set the valve tappets to .003 and .004, and removed the baffle to check for obstructions, no joy. I've ordered a carb kit, I'm just wondering if anyone has run into this one on the 70s before.

A couple things I'm looking into: the air cleaner was dry rotted from storage, so it is being run with no filter, I know this may throw off the jetting. The air mix screw did not have an o-ring on it ad they usually do, perhaps leading to an air leak. Any advice appreciated.

-Paul

[lndy650]

are you sure the pilot jet wasnt plugged? what does it do if you rev it up and turn the choke off? if it runs with no choke at higher rpms try getting a o ring for the air screw that could be doing it

[VABCH350X]

Cleaned the carburetor again today, and found a passage I may have missed last time. Cleaned the pilot and main out again wth a strand of copper wire. I also put the end caps on the airbox and swapped spark plugs. The machine runs a little better, and will now idle without the choke on, but will still bog and die when you give it gas. It will wind out somewhat on choke, but bog down the second you switch off choke.

I have ordered a carb kit, maybe changing jets will help. Think it could be a timing issue?

-Paul

[Jason Hall]

I bet the pilot and main still have varnish In them, on the walls of the jets bore. It's real hard to get all of It off. Changing them would be the way to go.

[VABCH350X]

Good call dude. When I swapped mains there was a noticible differece in the amount of light I could see though the jet. Though I cleared it with a strand of wire and blasted it with carb cleaner and air, it must have had some build up inside.

So now that it runs and looks great (my kids think its new even though its an 86) I guess I need the factory valve setting and air screw setting. I'm also lookng for a steering stem bushing (discontinued through honda). Thanks a lof for your help guys.
-Paul

[350Xhilaration]

Glad you got it running better. Your kids will love it. My 8 yr old loves hers.

We're taking a trip tomorrow to a local riding spot. Washed and gassed up all the rides today...first time in over 6 months since they had a bath.:crazy:

I'd like to get an 87 rear brake pedal assembly, other than that, it's the perfect kid quad.

Pics of my daughter's TRX...wow she was 5 then...8 now and TRX turned 22, not 19...need a site update I guess

http://www.350xriders.com/trx70

[VABCH350X]

Awesome machine dude, I think I lucked out too getting a clean little TRX. So the bike runs really nice now after installing the carb kit, but it still boggs down a little sometimes when you go from idle to full throttle. It has a new OEM air filter, and everything is factory, should I try to find a main jet a size or two bigger to remedy this situation? Good times,
-Paul

[J.D.]

Try moving your needle clip up or down, I have a similar problem to yours, but I found if my clip is at the top groove(lean) it seems to run better, and if I move it to bottom groove(rich) it will hardly take off.

[SYKO]

my daughters trx did that, after screwing around with the stock carb, I got fed up and threw it~! I ordered a cheap 25 buck china carb (also slightly larger) and it really woke the 70 up! she loves it. It starts right up, idles perfect and rips from the get go, plus after I dug the stock 70 carb out of the weeds I sold it on ebay for more then what I paid for the chingchong one! awesome!

[TravEX]

Lower your needle clip. The needle is lean. This was the case on both of mine, and many others here on the boards.

Syko, got a link to that carb???

[SYKO]

its just any of those cheap kazuma linglong ching chong bing bong carbs that are on ebay all the time, there are slight differences that I had to do about 5 mins worth of modding to make work, but that was simple I also put on a clamp on filter on the carb as well

[VABCH350X]

Went one notch leaner on the needle and it runs perfect. Good call on that one. Somewhat counterintuitive though, all indications were pointing to an already lean mixture. Thanks a lot guys.