10-27-2023, 10:24 PM | #1 |
Join Date: Oct 2023
Posts: 6
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Trailmaster tm31x carb
I recently purchased a trailmaster tm31x with the 223 engine. I am working on getting the carb better but still have a bog when snapping throttle. It removed the bowl screws and mixture screw plug. It came with a 40 pilot and 116 main. It seemed lean so went to 42/125. Didn't help much. Went to 45/130 and it seems worse. I am going to try 40/120 and see if I just missed the sweet spot but wondering what others have done. The needle is not adjustable. I would also buy a different carb if needed. Any help would be great. Thanks
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10-28-2023, 07:52 AM | #2 | |
Join Date: Oct 2021
Location: odessa MO; donna TX
Posts: 152
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10-28-2023, 08:51 AM | #3 |
Join Date: Feb 2021
Location: Kansas City
Posts: 2,625
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Hello kart, I have a 249.9cc OHC engine (the FMM172-3) with OEM intake, carb and exhaust system. It came with 40 pilot, 120 main. I tried 45 pilot and it was too much. 42.5 pilot jet was perfect. I bumped the main jet from 120 to 125. The needle in this OEM carb has only one position, so technically, it isn't adjustable...
But actually, it turns out that it is in fact adjustable. I learned how to do this many years ago on my Suzuki GS bikes. You can shim the needle with tiny washers and in fact, it is more adjustable doing this since you can shim to any position with combinations of thick or thin washers. I describe this for my Templar in the Templar resource (a sticky in the top of the dual sport section). It is post #5 https://www.chinariders.net/showpost...79&postcount=5 Mine didn't need much of a shim. One ~1mm thick washer was perfect. The process is described in that post. The washer does have a clip with only one position, so you remove the needle from the slide and place the washer uder the clip and put it back in. It is just as easy as repositioning the clip on an "adjustable" needle, but you can stack as few or as many washers there that you want. The retainer may not seem to fit right over the installed needle since the clip and washer are thicker than the clip alone. But the large slide spring holds that retainer down anyway, so it doesn't matter.
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-NOS 2020 KTM 250SX (2-stroke motocross) |
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10-28-2023, 09:18 AM | #4 |
Join Date: Oct 2023
Posts: 6
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Thanks for the responses. Yea this process isn't new to me, but have found this one more difficult. I also have a tao 140 that I put a vm26 on which virtually eliminated the bog. I understand that it won't be 2 stroke snappy but right now falls on it's face. I was going to run an get some washers for the needle today. I also adjusted the valves right away which needed it. I know some carbs just work better than others and thinking the stock carb just isn't one of them. I will try a few more things today and report back. Thanks again
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10-28-2023, 10:07 AM | #5 | |
Join Date: Oct 2021
Location: odessa MO; donna TX
Posts: 152
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10-28-2023, 03:07 PM | #6 |
Join Date: Oct 2023
Posts: 6
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Well no luck. Tried 40/120 and 42/120. It is much better but still sucks. Tried air screw from 1.5 to 2.5 in 1/4 increments. If you roll on the throttle slowly it is fine. But coming out of a corner or trying to get on power to wheelie over a jump it basically dies. Everyone seems to like nibbi carbs but I have tried 2 and had terrible luck. Anyone using one or have a carb suggestion?
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10-29-2023, 08:56 PM | #7 |
Join Date: Nov 2022
Location: Pennsyltuckey
Posts: 309
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Shim the needle with two M3 washers and check the float adjustment.
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22 Templar 250 |
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10-30-2023, 04:49 PM | #8 |
Join Date: Oct 2023
Posts: 6
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I did try the 2 washers under the needle as well. It maybe helped a little but the issue remains. I ordered a pe28 nibbi and will try that. It is frustrating because it is a fun bike to ride, but this is really annoying.
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10-30-2023, 09:00 PM | #9 | |
Join Date: Nov 2022
Location: Pennsyltuckey
Posts: 309
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Most PE28 ZS172 owners run 42/125 and the Nibbi guys recommend position #3 on the needle. I recommend starting at 1.5 turns out on the idle air screw. GL
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22 Templar 250 |
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10-30-2023, 09:20 PM | #10 |
Join Date: Oct 2023
Posts: 6
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I got the nibbi on. Similar issues. Could tell by the plug it was lean. Went to 45/130 and it is almost perfect. It was also 38 degrees here today so that doesn't help. I think a 135 main is next. It is already soo much better. Actually has power to wheelie! I will post what I end up with so others can use it.
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10-31-2023, 02:42 PM | #11 | |
Join Date: Nov 2022
Location: Pennsyltuckey
Posts: 309
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What's your elevation? I'm at ~400 ASL.
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22 Templar 250 |
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