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What jets to use in a TT-R 125

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I live in NC and my bike takes FOREVER to get cranked!!! Is jetting the answer to this? What jets should I use? My bike is bone stock. I an leaning towards a 110 main and 17.5 pilot. If anyone could help that would be great. :bonk:

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I gotta rejet my wifes ttr 125 too. It cranks good but it is very cold natured, gotta let it warm up really good before u cam take off.

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A 110 is perfect.

Java was talking about a 115 main, which is way too rich unless you have a supercharger. 17.5 pilot and a 110 main works every time.

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Did you get a response from java4u about how much the jets are? By the way how do these sizes sound to you?

Ya we talked, he sent me a link to JETSRUS were u can buy single jets instead of a whole pack, just gotta figure out which ones I really need.

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I've recently acquired an '02 TTR-125L, it was all stock when I first got it. After reading about mods and noticing how long it took to warm up and become rideable, I decided to remove the airbox screen and snorkel. I've also removed the airbox side cover when I'm not doing any wet mud, or muddy riding. I also cut open the muffler and modified it to a more "straight thru" design, but left the end cap on. it is quite a bit louder, but not ridiculously so. It actually sounds like a bigger full-on race MX bike, such as a yz250f or equivalent. after doing these mods I changed the jets out to 17.5 and 115 and it seems to have a bit more get up and go. it doesn't seem to be too rich on top, although at this point the only ridding i've done has been in very cool or cold weather. I plan on changing the main to a 110 when I get one from jets-r-us, and definitely before it warms up. I put the 115 in because that was all they had in stock at the local bike dealer. and I didn't want to run it with the 105 after opening up the air flow for fear of running dangerously lean. It starts up really easy, though it didnt start hard before the mods but i would usually have to start multiple times till it would stay running. also, it seems to warm up a bit quicker, doesnt have to have the choke on as long, and is more rideable from a cold start. anyway that's what I've done with mine, I would recommend at least swapping the slow jet out to the 17.5, even on a bone stock ttr I think it will help especially in cooler weather close to sea level. you can always adjust the fuel screw as needed. just as has been stated in many previous posts these bikes were jetted quite lean from the factory due to emissions standards and could almost all benefit from being jetted a bit richer. anyway that's my take on it.

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Never mind. I cleaned the pilot jet and main out. That fixed it right up! I think the previous owner left fuel in the bowl. Starts first time.

Edited by Dirt Bike Crazy
Added info.

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I think I'm still going to rejet. Where is the cheapest place to get jets. JETSRUS has outrageous shipping. Whould these jets work http://www.trianglecycles.com/Mikuni-GENUINE-MIKUNI-100-604-MAIN-JETS-detail.htm?productId=7944581&ez=Jets~q=tidaa1642zz~r=~ for main and this http://www.trianglecycles.com/Mikuni-GENUINE-MIKUNI-VM28486-PILOT-JETS-detail.htm?productId=8173038 for pilot? I live sort of near this place so I could go pick them up. But I cant get a response from them about these.

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I just posted a 112.5 Main and a 17.5 Pilot for sale in the classified section. Changing to these jets cleaned my bike right up. I have........errr, HAD, the same problem as everyone else: cold, cold, cold blooded! Anyways, PM me if you want one or both.

http://www.thumpertalk.com/classifieds/showproduct.php?product=75924&title=jetsmain-and-pilot-for-mikuni-vm20ss-yamaha-ttr125&cat=34

Jeff

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Besides the lean factory pilot, there is another problem with starting.

The tiny tube that fuel flows through from the starter enrichment plunger or choke gets pretty plugged also. That cuts down on the extra fuel being delivered for starting.

I have had to dig fuel residue chunks out with a dental pick.

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if you have an aftermarket air filter, or modded box, with aftermarket exaust and aren't to far above sea level it should be ok, especially during the cooler months. I've got a 115 in mine right now with gutted exaust and moddified air box and am not too far above sea level where I live, and its fine right now but I'm sure when it warms up it will be too rich.

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Besides the lean factory pilot, there is another problem with starting.

The tiny tube that fuel flows through from the starter enrichment plunger or choke gets pretty plugged also. That cuts down on the extra fuel being delivered for starting.

I have had to dig fuel residue chunks out with a dental pick.

How would I do this. And what tube are you talking about? If you want you can send pics to wawall@triad.rr.com

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I don't have any pictures, or a 125 any more. Sorry!

Look at the passage that the choke plunger uncovers, and see how it allows additional fuel into the carb. That passage is micro sized and easily clogged.

The carb on those bikes is the main source of irritation. If you could get it to work all the time, these would be the most popular small bikes ever, even surpassing the XR100. Maybe they already have.

But...they just don't tolerate sitting for months at a time. If you want to love your bike, start it once a month and let it warm up for 5 minutes, or better yet, ride it up the street. It's easy to forget to do when it is cold out, but it is the single best thing you can do to keep the carb situation manageable.

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