Author Topic: carb question on frame off restore (with pics) (Read 2165 times)

Downrangecop · « **on:** June 18, 2015, 11:59:00 am »

Hey guys, just finished rebuilding an 89 LT250r with my 15 year old and it came out great. Check out the pics. Anyway the carb is probably toast. Had it rebuilt and it still leaks out of the bowl like crazy. Buying a new Mukini is like $350. Ive seen the Keihn's on ebay for a lot less.

http://www.ebay.com/itm/Suzuki-LT250R-34mm-Keihin-PJ-Carb-Carburetor-1-Carb-LT-250R-/311366165001?hash=item487edea209&vxp=mtr

Anyone have any experience with these or is there a better carb to swap out. Not going for extreme power, it's a basic build for my boy.

Thanks!

MotorGeek - Jerry Hall · « **Reply #1 on:** June 18, 2015, 01:52:51 pm »

Quote from: downrangecop on June 18, 2015, 11:59:00 am

Hey guys, just finished rebuilding an 89 LT250r with my 15 year old and it came out great. Check out the pics. Anyway the carb is probably toast. Had it rebuilt and it still leaks out of the bowl like crazy. Buying a new Mukini is like $350. Ive seen the Keihn's on ebay for a lot less.

http://www.ebay.com/itm/Suzuki-LT250R-34mm-Keihin-PJ-Carb-Carburetor-1-Carb-LT-250R-/311366165001?hash=item487edea209&vxp=mtr

Anyone have any experience with these or is there a better carb to swap out. Not going for extreme power, it's a basic build for my boy.

Thanks!

There is only 5 things that will cause the float bowl to overflow.

1. A bad needle or seat
2. A bad o-ring on the outside of the seat
3. Improperly adjusted floats
4. Debris trapped between the needle and seat.
5. Heavy floats

I have not seen any heavy floats on the plastic floats. Brass floats sometimes get a hole in them and fill up with fuel.

Needle seat assy.are about $25.00 and o-rings are about$2.00

I would have someone that knows what they are doing take a look at the carb. They missed something real basic if it is still overflowing.

92lt250wannabe · « **Reply #2 on:** June 18, 2015, 06:14:46 pm »

you can get a stock lt250r mikuni tm34 on amazon for 134.00 free shipping. fixing your carb is probably cheaper but Im just lettin you know what I found for ya. I just picked up a tm38 for my lt250 (zilla carb swap) and i got it for 136.00 shipped

El Diablo · « **Reply #3 on:** June 19, 2015, 03:54:51 pm »

X2 with Amazon. I got a TM-38 for my 250R for $134. Look for the TM-38-89. It will slip into the stock LT-250 carb boot.

92lt250wannabe · « **Reply #4 on:** June 20, 2015, 07:47:22 pm »

The carb I picked up was the tm38-85 it has the larger spigot mount, 47mm spigot. Heard it's the better of the two models. If a guy ever wants to get it bored it's able to be bored bigger without issues. Just what I was told.

Downrangecop · « **Reply #5 on:** June 24, 2015, 04:35:30 pm »

Quote from: 92lt250wannabe on June 18, 2015, 06:14:46 pm

you can get a stock lt250r mikuni tm34 on amazon for 134.00 free shipping. fixing your carb is probably cheaper but Im just lettin you know what I found for ya. I just picked up a tm38 for my lt250 (zilla carb swap) and i got it for 136.00 shipped

Sorry Internet is down and I'm answering on my phone. I copy the needle/ seat issues. They're new and seating fine. The float was bent (presumably a backyard fix by the former owner) and you have to bend it so far down that it would risk stalling out on big dunes. That's why I thing it'd be easier just to go new carb. Thanks for the info guys I'll be on Amazon tonight.

Downrangecop · « **Reply #6 on:** July 06, 2015, 08:24:48 pm »

OK guys I got the carb and went to drop it in today... the TM38-85... sure enough it wont fit the boot on the 89. What size do I need?

Skeans1 · « **Reply #7 on:** July 06, 2015, 08:32:14 pm »

Buy an 88+ Zilla boot for the motor side, the airbox side boil the boot to soften it and stretch it on the carb.

Downrangecop · « **Reply #8 on:** July 06, 2015, 09:19:19 pm »

Ok. Is the Zilla boot a straight fit? I've read that it sits off to the side too much.

Glamisrider · « **Reply #9 on:** July 07, 2015, 02:32:34 pm »

Quote from: Downrangecop on June 24, 2015, 04:35:30 pm

They're new and seating fine. The float was bent (presumably a backyard fix by the former owner) and you have to bend it so far down that it would risk stalling out on big dunes. That's why I thing it'd be easier just to go new carb. Thanks for the info guys I'll be on Amazon tonight.

I'd bet you got stuff stuck in the needle/seat area.

Every time we've been riding and someone is just flowing gas from their over flow this is exactly the issue.

Piece of hose, dirt, rock, some other debris is stuck in there and won't allow it to close and shut off the fuel flow.

1) Take and carb apart.
2) Take the bowl off
3) Take the main out of the bottom
4) Remove the plastic circle retaining ring
5) Remove the pin & float adjustment tab
6) When this comes out the needle should be hanging on the center of the float adjustment.
7) check for debris under the float needle and where it seats.

92lt250wannabe · « **Reply #10 on:** July 10, 2015, 01:46:41 pm »

I don't know if the zilla intake boot off the motor would be too much of an angle or not. If you ride dunes a lot you can always get an uni dual stage filter and connect it right to the carb. Lots of folks do that. I have a 92 so I couldn't do that, I picked up a zilla airbox outlet pipe To go around the rear shock. Those uni filters come in just about any id to match the od of the carb. And they do have 4" long and 6" long versions if space is tight. But I do know guys get those carbs in the stock intake boot after boiling them.

Dutch_Rutter · « **Reply #11 on:** July 13, 2015, 10:15:01 pm »

I am one who got that 38mm carb in both of those stock boots, motor and airbox side I ended up using my Wife's hair dryer. it was still a huge fight, I thought I was going to rip the boot but it stayed together surprisingly enough.

Downrangecop · « **Reply #12 on:** July 22, 2015, 09:19:47 pm »

Ok sorry for the delayed update but I've been working like crazy. So I got the carb in with the lt500 intake and ran the two stage uni filter with an outerwear (no airbox). With the jets that came with it it will fire right up, but as it warms up, or when you give it throttle, it will runaway accelerate (like you have an air leak). Question is am I so far off base jet wise that it's causing this or is there an air leak somewhere that's causing it. To be safe I removed the intake and made sure the gaskets and a good seal. Intake boots all seal properly as well. Really it only leaves improper jetting/ tuning. Any recommendations for a baseline/ starting point? Bike has an fmf pipe, otherwise stock, and we are at sea level. I run 50:1 bel ray and 91 pump gas.

Downrangecop · « **Reply #13 on:** July 22, 2015, 09:29:50 pm »

And thank you glamis I had already purchased the new equipment, but kept the stock stuff as well just in case.

Glamisrider · « **Reply #14 on:** July 28, 2015, 11:48:43 am »

Please update us with your new set up including exact jetting specs.

Thanks

All American · « **Reply #15 on:** September 20, 2015, 05:58:25 am »

Quote from: Downrangecop on July 22, 2015, 09:19:47 pm

Ok sorry for the delayed update but I've been working like crazy. So I got the carb in with the lt500 intake and ran the two stage uni filter with an outerwear (no airbox). With the jets that came with it it will fire right up, but as it warms up, or when you give it throttle, it will runaway accelerate (like you have an air leak). Question is am I so far off base jet wise that it's causing this or is there an air leak somewhere that's causing it. To be safe I removed the intake and made sure the gaskets and a good seal. Intake boots all seal properly as well. Really it only leaves improper jetting/ tuning. Any recommendations for a baseline/ starting point? Bike has an fmf pipe, otherwise stock, and we are at sea level. I run 50:1 bel ray and 91 pump gas.

Finally somebody other than me who uses Bel Ray. Are you using H1R or MC1?

Throttle Therapy · « **Reply #16 on:** December 24, 2015, 10:58:48 am »

Runaway idle could be crank seal

Sublunacy · « **Reply #17 on:** December 25, 2015, 04:16:32 pm »

Quote from: Downrangecop on July 22, 2015, 09:19:47 pm

Ok sorry for the delayed update but I've been working like crazy. So I got the carb in with the lt500 intake and ran the two stage uni filter with an outerwear (no airbox). With the jets that came with it it will fire right up, but as it warms up, or when you give it throttle, it will runaway accelerate (like you have an air leak). Question is am I so far off base jet wise that it's causing this or is there an air leak somewhere that's causing it.

-------
thats how 2 strokes run when they are lean if im reading the post correctly.

All American · « **Reply #18 on:** December 28, 2015, 02:04:21 am »

My dad says if it's not smoking, it's not got enough oil in it. I personally don't know how true that is. Air leak would be what I look at after I drain fuel and mix it with more oil. If the problem persists, an air leak down tester would answer your question.

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Author Topic: carb question on frame off restore (with pics) (Read 2165 times)

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