17 replies to this topic

[Terry]

I have a '74 TL125 and the origional carb body is warped and the slide sticks so bad it is unusable. Has anybody run across another carburator that works on the TL that might be easier to find? It seems I remember someone saying a XR75/80 carb will work but I haven't checked and would assume it would need rejetting. What should I be looking for?

Edited by Terry, 16 February 2009 - 07:35 PM.

[wayne_weedon]

Does it still stick when the nuts are slackened off?

The plastic spacer/insulator is prone to becoming compressed and no longer flat over time and causing the carb to distort when pulled up snug.

You may only need to correct the spacer.


Wayne....

[RMXBOY]

Hello Wayne, I cant be one hundred percent sure but I know that a carb rebuild kit for an xr 75/80 fits the tl 125 carb. The needle needs to be about 43mm long. I know the SL 125 carb is a lot taller and the bowl is larger because a carb kit for a SL 125 was no use to me. Any donor carb needs to be 64mm from front to back ( flat mating surfaces) , the inlet into the manifold is 22mm dia and the 6mm bolts for the manifold are at 48mm centers. The standard TL main jets are 95 or 98 and the pilots are 35 or 38 depending if its an "s" or not. The diameter where the boot from the airbox fits is about 32mm. I measured a carb at the weekend looking for some causes to an issue that I have. Hope this helps.

[RMXBOY]

Sorry forgot to add. Drop the guys at Re-MX.com an email about replacement carbs. I have had a price of $122 usd to New Zealand so you can probably get one cheaper than that. That is a carb that will work on a TL and a jet kit to fine tune it.

[Terry]

Thanks. Mine sticks with the carb off the bike. You can hardly get it out. I wish I had a place to go check out a bunch of salvage bike and find what would work. Just trying to find out how others solved the problem.

[TLrider]

Terry,

Is your carb clean? I bought a used Tl125 S 'parts' carb, the 76 model which is much better by the way, that was so dirty the slide was stuck. I soaked it for days in carb cleaner and finally got it unstuck. With cleaner and very light usage of Scotch-Brite (the scouring pad on the back of your kitchen sponge) I cleaned all of the corrosion and varnish from both the slide and carb. It's been on the bike for at least 3 years now.

On the spacer getting flattened over time, well I'm not sure about that. I have another S carb in like new condition which is not flat on the spacer side. I machined some of my own spacers which are exact copies and I made the mating surface curved. THe o-ring seals and the ears of the carb flange bottom on the outer edges of the spacer so I can't distort the body. It's been on the bike as long as the aforementioned carb.

RMXBOY is correct. Re-MX has the XR75 carb which is the same except for jetting. I live close to them and would be happy to see if the carb flange is flat. Seeing an NOS carb and/or spacer is probably the only way to be certain.

The SL125 carb is 22mm where the TL/XR carb is 20mm, been through that. I have heard of people using it however.

I have seen repro TL125 S carbs on ebay. They are out there. THe S carb has the screw on bowl, the carb body has been thickened and a gusset added vertically along the barrel on the flange side to prevent distortion and the slide wall thickned as well. Overall a much better carb than the K model. I bought one of the repro SL125 carbs mentioned above and I must say the visual quality is quite good and the fit between the slide and barrel seemed correct. I'm sure it was from China and i'm guessing they either bought Keihens obsolete tooling or reverse engineerd it.

Scooter

[RMXBOY]

Scooter. Do you know if the "S" carb is the same as anything else of that era? or is it TL specific. Are the XR 100 carbs 22mm and higher bodied like the SL 125s. Thanks

[Terry]

Scooter, if you are going by the shop and can eyeball the xr75 carb I would appreciate it. I have a friend that has a machine shop and I could get him to machine a spacer for me. Did you use alunimum to machine yours out, sounds like it is holding up good. How did you isolate the heat transfer from the cylinder to carb or have you had any problems with that? Sorry for all the questions but if you never ask...................

[TLrider]

RMXBOY,
According to the TL parts list both the 'K' and 'S' carbs have the TL's product code of xxxxx-355-xxx. To the best of my knowledge the product code denotes the model the part first appeared on. The part can and may have been used on subsequent models as many of the TL parts are carry overs from the CL (?) and SL 125. If the 'S' carb was used on anything else I don't know and really have no idea how to find out with out looking at part numbers for other bikes. I do know the 'K' and 'S' are jetted differently.
The 73-75 XR75 carbs are 20mm but the flange holes are at an angle as opposed to horizontal. I think they first appeared on the XR so they would have a different product code. The carb Re-Mx has for the 76 and later XR75 appears to be the same body as the 'S' and we believe only the jetting to be different.
I'm going to take my spare 'S' carb there and do a side by side comparison.
Sorry to say I have no idea on the 22mm XR100 carb.

Terry,
Sheng Wey is a Chinese carb maker that I believe makes a repro S carb but I can't find one on the net anywhere. I've seen them on ebay in the past though that's of no help now.
B&J Racing offers a bolt on replacement I have been told is off a late model XR100. If you want an authentic appearance go with the one from Re-Mx and get a jetting kit which are available on ebay from Sirius Consolidated I believe, they're listed frequently.
Any specifics you are looking for on the Re-Mx carbs? They have OEM and repros. I drive by them on my way home from work so stopping by is not a problem.

I believe I made the spacer from Garolite XX which is a paper based phenolic. I thought I ordered a flame resistant variety but I can't find what I think I ordered from McMaster-Carr.
The material would barely burn with a flame held to it and would go out immediately when the flame was removed. I also oven tested it at 350 F for about 3 hours. Being a phenolic there is minimal heat transfer. It is made to 'S' specs, major difference is the heat shield is 1/8" thick as opposed to the 'Ks" 1/16". I really should post a photo, from standing distance you can not tell it's a repro. I've thought of making another batch with the plan of putting an o-ring on the cylinder head side and eliminating the gasket. I need to check operating temps for o-ring materials first. The other change may be to reduce the taper of the spacer from the carb to the head, this would increase the air velocity somewhat.

No worries on the questions. I'm happy to share some of my knowledge in exchange for useful info I've gathered here over the last several years.

[RMXBOY]

Scooter, regards the heat sheild between the carb and manifold. Have you run a bike without it? I have never had one on the bike that i have. Can you give me some dimensions for the sheild and I will make one and see if that helps with my issues.

[Terry]

As far as Repro or OEM, I don't care because I am building this to ride. I am not trying to restore it. I am really looking for what will work best and is obtainable. If you don't mind the questions, please check out my other post about removing the clutch. Thanks for your help on carbs, nobody around I can ask.

[RMXBOY]

Hello Scooter, I recieved an email from Re-MX to say that some one had dropped by with an "S" carb. I quess that was you. He said that the xr 75 carb would work and that he has jets to fit. He also said that the "S" carb had a 105 main jet in it. is this the size that you are running.? what pilot jet do you run in a 125s motor. That is pretty neat that you live nearby and can call in and check over the parts. Living at the bottom of the globe I need to trust what the seller tells me and take a gamble on any purchases. Thanks

[TLrider]

RMXBOY,

I have not run my bike without the heatshield. A couple of years ago I rode the Trial at AMA Vintage days at Mid-Oho. It was a hot July day, short loop, looooonngggg lines at the sections. Another TL rider was having problems keeping his bike running. I saw him alittle while later running smoothly. He had jury rigged an aluminum foil heat shield between the cylinder and carb so I guess it works.

Dimensions: same width as the flange @2.4" , length to bottom of float bowl @ approximately 3.2". THe flange is an extension in the same plane as the head side of the insulator, it is one piece. The 'K' model flanges were .0625"(1.5mm) thick. Most of them are broken since the easiest way to break the bond between the gasket and head was to use the flange as a lever, so they broke. I made mine to the 'S' thickness of 1/8" (3mm). I'm taking these measurements from a carb in hand. The bike is elsewhere so I can't give you the total block thickness. I presume yours is a broken original.

I forgot to bring the camera home from work so I can post a photo, still digitally challenged here.

Scooter

[TLrider]

Terry,

Yes I'm the guy with the 'S' carb. I stopped in Friday evening and it is nice to be able to stop and check on things. I'm glad to know they contacted you. You must have already made an inquiry. Nice folks, very helpful.
The carb he has is a Sheng Way made in Taiwan. The quality looks very good. We put my OEM jets in it so the threads are the same, looks to be an identical copy. As I said earlier they may have bought Keihin's obsolete tooling. I know that is not an uncommon practice.
I'm confident it will work for you.
The carb I took in has not been on my bike, it is a spare. I bought it off ebay listed as an 'S' carb. The one on my bike, also an ebay 'S' carb is almost identical. THe one on my bike has the number PC 04A. THe one I compared to Re-Mx's has the number PC 04B. The A carb has a few additonal gussets and what appears to be a vent or overflow hose just in front of the fuel inlet about 1/2 way up the barrel. The B carb has just a tiny hole where the vent/overflow hose is on the A. THe B has the important gussets along the barrel.

Both carbs have a 38 pilot jet, mine had a 105 vs. an 89 main jet. I'm not sure what size main is on the bike. I'll check and let you know but I can't get to it for a week or two.
Remember I have a 168cc big bore and at one time I drilled my pilot jet larger which helped with idle and the off idle cough, it doesn't.

The bottom of the globe? I guess you don't have overheating problems in Antartica....where are you?

YOur welcome, I'm glad to have helped.

Scooter

[RMXBOY]

Scooter I am in the North Island of New Zealand. Although it is summer here we only have moderate temperatures. Because my bike is a project made form three wrecks I have never had a heat sheild and am never quite sure what is standard on these. What material did you make the heat sheild out of. I must apologise for getting this thread side tracked. The internet sure makes the world a smaller place. regards Jeff