05 TTR-230 Carb Rebuild - Help Request

[Tim Kirchner]

Hi All,

My 05 TTR-230 wouldn't start after sitting for a very long time while I was deployed...did some trouble shooting and narrowed it down to a carburetor issue...Decided on a complete rebuild to see if that was going to fix it. While I was at it I figured I'd go ahead and "uncork" it with the new jets (130/38) as documented here many times over. Also did the Air box mods...will probably leave the exhaust alone as I have no idea whether I'll need a functioning spark arrestor in the future.

Anyway, on to the question...I pulled the carb apart and instantly found what I assume was the problem: I was completely missing the o-ring/gasket on the starter (choke) well (part # 5Y1-14536-00-00, labeled 20 in the schematic below). I assume my starter plunger was completely ineffective without it. Also doesn't help that it freezing outside in PA in January...so trying to start the bike with no choke was an impossible task even with lots of starter fluid. But as I was cleaning the float bowl I realized that I also can't get any carb cleaner to flow from the hole in the bottom of the bowl into the "starter well" (I'm sure I don't have the terminology right, but I am talking about the separated compartment that the starter pipe draws it fuel from, the one my missing gasket goes on). I'm not nuts am I? Fuel should flow from the bowl into this separated fuel compartment through the small hole in the bottom of the float bowl? When I shine a light down the compartment, there is obviously some sort of jet or valve down there that restricts flow somewhat but it isn't a replaceable part...at least not on the carb diagram. Is it just clogged? any suggestions for getting it unclogged, did an overnight soak, toothbrush, air...even ventured to stick a wire down there but it was too large a gauge to fit into the smaller hole within the hole.

Any help or ideas would be appreciated...Thanks, Tim

[Tim Kirchner]

Also as an interesting note, the "starter well" I refer to above is actually positioned inside the float bowl gasket unlike the schematic. Though I know I have the right schematic from yamaha.

Also, the "starter pipe" I mention isn't pictured in the schematic...it is part of the carburetor assembly itself and should be positioned between the pilot screw (part 7) and the pilot jet (part 6) extending straight down and mating with the "starter well" when the float bowl is attached. I have no problem getting carb cleaner to flow from the "starter pipe" into the starter plunger receiver and, when the plunger is installed and pulled out (choke on), into the vacuum tube so that half of the starter system is working. Will the fuel only flow into the starter pipe from the float bowl when there is a significant vacuum force drawing fuel?

[Leardriver]

You're right on your troubleshooting.

The tube that the choke (which is really an enrichment circuit) draws fuel from is vacuum fed and easily clogged. There is no pumping mechanism.

The TTR 125 carb is even smaller and worse. Anyway, It is a small pipe, and must be unplugged. Try a sharp piece of wire, compressed air, whatever you can think of, to unplug it. I have used a dental pick before.

Sitting is horrible for a motor with modern fuels. You are using fresh gas, I hope? How did an oring magically dissapear when the bike was just sitting? Did it run ok before you let it sit?

Edited January 28, 2012 by Leardriver

[Tim Kirchner]

Thank you! I'll keep working to get it unclogged. Glad to know I'm on the right track at least. Since it was being so stubborn, I was just concerned that I had somehow missunderstood where it draws its fuel from and fuel wasn't supposed to flow through there at all.

Sitting is horrible for a motor with modern fuels. You are using fresh gas, I hope? How did an oring magically dissapear when the bike was just sitting? Did it run ok before you let it sit?

Well, long story ...About three years ago, shortly after I bought it, it wasn't running very well, incredibly hard to get started, etc...I was relatively new to any kind of mechanics and had no idea Thumper Talk or any of the other amazing forums out there existed. A friend told me to rebuild the carburetor and that would certainly solve it. Nervously, I pulled the carb out and dissassembled, cleaned (well, half cleaned because I had no idea what I was doing), and reassembled without actually doing a proper rebuild. I suspect that is when I lost the o-ring...I didn't have a diagram or anything, I was just winging it. Reinstalled the carburetor, got it to run, still not very well though. and deployed to Afghanistan a couple of months later. The bike went to my mechanic father-in law while I was over there for a year. He rode it every so often (when he was willing to let his 2 stroke mx bike sit), tinkered with the jets, regular maintenance, but also never got it running properly. When I returned I moved to PA in the fall, and it started at that time, but I stupidly let it sit for that entire winter without draining the fuel. Wouldn't fire up the next spring...I was crazy busy at the new job, was TDY for 8 weeks that summer, was enjoying my new road bike I got when I returned.... so it sat. Finally, this fall I got the bug to ride again, invested the time to learn a bunch about carburetors and my bike, drained some fuel that came out looking like apple cider and pulled the carb. Put the project on hold again for work reasons but am now back to it.

Yes, new fuel now but I am still waiting for that o-ring to come in so I don't know for sure that fuel isn't flowing through that hole. It's just not flowing freely without a vacuum.

[Dirt Bike Crazy]

Try putting the smallest allen wrench in there. thats what i did. But I had a super tiny one.

[Tim Kirchner]

My .05in allen won't fit, or the smooth end of my 1/16 drill bit. off to find some smaller gauge wire.

[Tim Kirchner]

Got it done with a sewing needle! Flowing freely now. Thanks again...I'll let you know how it goes once my o-ring comes in.

[Leardriver]

I think you will be very pleased now that you have fuel flowing to the starter enrichment circuit. It may actually start!

[wrwest]

Chap do the free mods on your bike - verry easy and worth it.

[Tim Kirchner]

The "free mods" are just the re-jetting, air box, and drilling the holes in the spark arrestor, as documented in the project yamaha that offroad.com did many years back? http://www.off-road.com/dirtbike/project/project1554.html

I rejetted with the 130/38, the carb rebuild kit was on backorder for a couple months and I am impatient so I just ordered the two specific gaskets I need (the enrichener circuit gasket and the float bowl gasket) rather than waiting for all the...gave the whole carb a good scrub down. I drilled holes in my airbox and gave my filter a good clean...don't really want to drop money on a K&N right now but will probably do so in the future. I am really reluctant to destroy the spark arrestor because I move every three years and don't know when I'll need one to be legal. Any other cheap/free options to open up the exhaust that will be legal where ever I am?

I also ordered a 15 tooth CS Sprocket so will swap that as soon as I come in...

What else?

[Tim Kirchner]

Just checked, apparently no K&N for the ttr230? A Twin Air is only $30, maybe I will do this sooner than later.

[Tim Kirchner]

Bike starts!!! Also needed a new spark plug and opted for a new battery. The bigger jets are great, can lose the choke after a couple minutes of warm-up...Thanks for your help.

[Leardriver]

Good deal!

Those TTR 230's are crazy fun bikes, and more competent on the trails than they have any right to be.