Are mikuni tmx35 carbs any good?

Got questions? We got answers....
Post Reply
User avatar
Actionman
Supporting Member I
Supporting Member I
Posts: 621
Joined: 09:08 pm May 22 2013
Country:
Location: Parts unknown

Are mikuni tmx35 carbs any good?

Post by Actionman »

I was checking out the rm125(1990) I bought and the mikuni tmx carb is like new. Are these carbs any good compared to pwk keihins? I'd almost like to try it on my Kdx just to see if, jetted correctly, they add anything to the bike. I know that keihins are usually better, but I'm curious.
2002 KDX 200
User avatar
Julien D
KDXRider.net
KDXRider.net
Posts: 5858
Joined: 07:53 pm Nov 07 2008
Country: USA
Contact:

Re: Are mikuni tmx35 carbs any good?

Post by Julien D »

I think the TMX would be a step back from the PWK.
Image
User avatar
Actionman
Supporting Member I
Supporting Member I
Posts: 621
Joined: 09:08 pm May 22 2013
Country:
Location: Parts unknown

Re: Are mikuni tmx35 carbs any good?

Post by Actionman »

Yep. I figured it. Poor mikuni; every time I read a hop-up article in the 80-90s they would remove the mikuni and put a keihin on it. I read my old mxa mags about the late 90's bikes with mikuni a and they seem to have a ton of jetting issues. Shame, cause the rm's tmx looks like it just came outta the box.
2002 KDX 200
Roadhazardguy
Supporting Member II
Supporting Member II
Posts: 302
Joined: 09:18 pm Aug 13 2012
Country:
Location: Canyon Lake Tx

Re: Are mikuni tmx35 carbs any good?

Post by Roadhazardguy »

The TMX is a pilot-less Carb which makes it not so desirable, some of the atk 406 years came with a 38mm version but my year happened to come with a TMS which has a pilot. I traded it out for a 39mm PWK anyway but I just started having some fuel staring issues so I'm going to try to raise the float some more but if that doesn't help I'll give the TMS another shot. I have a race Sunday so this is the perfect time for it to start giving me problems...
Tony
1988 KDX 200
1980 KD 80
1989 ATK 406
1984 RM 500
1980 KZ 1300
2008 SM450R
User avatar
KDXohio
Supporting Member
Posts: 825
Joined: 06:04 pm Jun 19 2013
Country: United States
Location: Dayton, Ohio

Re: Are mikuni tmx35 carbs any good?

Post by KDXohio »

What size is the E series pwk is it a 35mm? and which slide number is stock?
1990 KDX200 FMF Fatty, Answer VFC silencer, VForce 3 Cage, Wiseco Piston, KX125-J series KYB USD fork conversion, Race tech goldvalves, J series front brake assembly, air-box snorkel removed, Acerbis Headlight, KX450F Front fender, Pro Taper RM bend bars, ASV front Brake lever, MSR Clutch perch and lever, RB Head mod, 36mm PWK carb, Trail Tech Kickstand.
User avatar
Actionman
Supporting Member I
Supporting Member I
Posts: 621
Joined: 09:08 pm May 22 2013
Country:
Location: Parts unknown

Re: Are mikuni tmx35 carbs any good?

Post by Actionman »

Roadhazardguy wrote:The TMX is a pilot-less Carb which makes it not so desirable, some of the atk 406 years came with a 38mm version but my year happened to come with a TMS which has a pilot. I traded it out for a 39mm PWK anyway but I just started having some fuel staring issues so I'm going to try to raise the float some more but if that doesn't help I'll give the TMS another shot. I have a race Sunday so this is the perfect time for it to start giving me problems...
This is the tms with pilot and main. Its a 35mm carb. Mikuni has terrible identification on their schematics and its confusing to try and figure out which is which. I remember in old mxa mags this carb was Identified as tmx I thought. Eh, whatever. Still a shame as nice as it is that I can't use it.
2002 KDX 200
Roadhazardguy
Supporting Member II
Supporting Member II
Posts: 302
Joined: 09:18 pm Aug 13 2012
Country:
Location: Canyon Lake Tx

Re: Are mikuni tmx35 carbs any good?

Post by Roadhazardguy »

Well if its the TMS then it wouldn't hurt to try it out. A lot of the ATK guys love them if they're set up properly.
Tony
1988 KDX 200
1980 KD 80
1989 ATK 406
1984 RM 500
1980 KZ 1300
2008 SM450R
User avatar
Actionman
Supporting Member I
Supporting Member I
Posts: 621
Joined: 09:08 pm May 22 2013
Country:
Location: Parts unknown

Re: Are mikuni tmx35 carbs any good?

Post by Actionman »

I got bored today and installed the tmx and throttle cable on my Kdx. I know I may get disbelief from some folks, but my bike actually ran awesome with it! The air boot was a good fit, and the intake boot fit as well, but it may need a tighter clamp for peace of mind- but it was absolutely nearly spot on jetted as far as I could tell! I didn't rev it out in top gear so it may need main adjusting, but the starting, low and mid throttle settings were right on! No more slight bog at 1/4 throttle that I can't get rid of with the pwk! It ran like a new bike, comparatively. My pwk needs a new float cause they're a little crooked, and that may get it right, but I'm clamping the tmx down and riding a few time to see how it goes. so far I like it! I may even sell my pwk if it turns out as good as it felt today.
2002 KDX 200
User avatar
KDXohio
Supporting Member
Posts: 825
Joined: 06:04 pm Jun 19 2013
Country: United States
Location: Dayton, Ohio

Re: Are mikuni tmx35 carbs any good?

Post by KDXohio »

Mikuni has always been good to me but I've never changed out carbs on anything
1990 KDX200 FMF Fatty, Answer VFC silencer, VForce 3 Cage, Wiseco Piston, KX125-J series KYB USD fork conversion, Race tech goldvalves, J series front brake assembly, air-box snorkel removed, Acerbis Headlight, KX450F Front fender, Pro Taper RM bend bars, ASV front Brake lever, MSR Clutch perch and lever, RB Head mod, 36mm PWK carb, Trail Tech Kickstand.
User avatar
Actionman
Supporting Member I
Supporting Member I
Posts: 621
Joined: 09:08 pm May 22 2013
Country:
Location: Parts unknown

Re: Are mikuni tmx35 carbs any good?

Post by Actionman »

My keihin needs a float because I noticed one is higher than the other and the metal piece is twisted. I'm sure that's causing me grief, but even though I've got the pwk jetted to what I believe is correct settings it STILL had a little richness in the 1/2 to nearly fully open setting. My needle is in the top clip so I think I need a leaner needle but I've asked on numerous forums which needle is leaner and haven't gotten any replies. Anyway though, I assumed the tmx would be way lean but it ran pretty sweet. Throttle response is better, idle is way smoother, it's clean as a whistle til right before full throttle. Ill get a chance to test the main jet tomorrow. I seriously may keep it on my kdx; it runs that well.
2002 KDX 200
User avatar
Julien D
KDXRider.net
KDXRider.net
Posts: 5858
Joined: 07:53 pm Nov 07 2008
Country: USA
Contact:

Re: Are mikuni tmx35 carbs any good?

Post by Julien D »

I can run some graphs and show you some leaner needles tonight.

Sent from my HTC6435LVW using Tapatalk 2
Image
User avatar
Actionman
Supporting Member I
Supporting Member I
Posts: 621
Joined: 09:08 pm May 22 2013
Country:
Location: Parts unknown

Re: Are mikuni tmx35 carbs any good?

Post by Actionman »

Julien D wrote:I can run some graphs and show you some leaner needles tonight.

Sent from my HTC6435LVW using Tapatalk 2
Thanks julien! I think one step leaner needle will have my pwk running fine. I going to order a few jets for the tmx and continue experimenting though. I went for a quick ride today and I swear it seems to be jetted pretty well. You'd think it would be too lean considering it has stock rm125 jetting, but it feels more spot-on than I've EVER had the keihin. Weird, but pretty cool.
2002 KDX 200
User avatar
Julien D
KDXRider.net
KDXRider.net
Posts: 5858
Joined: 07:53 pm Nov 07 2008
Country: USA
Contact:

Re: Are mikuni tmx35 carbs any good?

Post by Julien D »

Did you check your needle to see if it was 1173n or 1174n? Of those two stock needles, 1174 is the leaner. In OEM jets the 1173 is a BGP and the 1174 is a BGQ. The numbers don't port directly over from kawi part number to OEM. Two of the measurements are transposed. Check the needle guide in the jetting section for detailed information. It will really help with your needle choice. Alot of people have had great luck with the CEL and DEL needles, but it will require you to re-jet, yet again. With either of those needles, you'd have to drop down probably a couple sizes on main and pilot. The overall fuel curve looks much better with those changes.
Image
User avatar
Actionman
Supporting Member I
Supporting Member I
Posts: 621
Joined: 09:08 pm May 22 2013
Country:
Location: Parts unknown

Re: Are mikuni tmx35 carbs any good?

Post by Actionman »

Thanks julien! I feel that my needle needs another slot to raise it another clip, so it's pretty clear I need a leaner one. My final jetting was 38 pilot, 155 main, stock needle in top clip, and airscrew 1 2/3 out. I have the airbox lid on with snorkel because I like how quiet it is, and even though its a noticable improvement without it, the increase in noise isn't worth it. My bike is very, very peppy even with the lid on, but I still have a minor rich spot right before I fully open the throttle completely. I am assuming its the needle; I can't imagine I need a leaner main.
2002 KDX 200
User avatar
Julien D
KDXRider.net
KDXRider.net
Posts: 5858
Joined: 07:53 pm Nov 07 2008
Country: USA
Contact:

Re: Are mikuni tmx35 carbs any good?

Post by Julien D »

155 seems fat, considering the pilot ended up at a 38, and with the super restrictive airbox lid still in place. If you want to change the needle, I would go to the cel or del. Cel has a lot more snap when the powervalves open, the del is much more linear. The cel can be fun, but tiring. I advise getting both and going back and forth a bit. Your main would probably need to go way down with either of those needles. A 150 with a DEL gives roughly the same fuel mixture at 3/4 throttle as your 155 with a BGP (1173N), while being just a little leaner at WOT. The CEL/DEL will also be richer at idle - 1/4 throttle, but I can't imagine needing to drop below a 38 on your pilot.

Sent from my HTC6435LVW using Tapatalk 4
Image
User avatar
Actionman
Supporting Member I
Supporting Member I
Posts: 621
Joined: 09:08 pm May 22 2013
Country:
Location: Parts unknown

Re: Are mikuni tmx35 carbs any good?

Post by Actionman »

When my jetting was screwed up a 158 felt too lean! It popped surged and banged. Now a 155 winds out hard and feels pretty good. Ill buy the jets you suggested and do some testing. I'm still buying tmx jets as well, but ill probably go back to the keihin . I'm always fearful of running lean , but my plugs look pretty good-albeit with a slightly dark tint.
2002 KDX 200
User avatar
Julien D
KDXRider.net
KDXRider.net
Posts: 5858
Joined: 07:53 pm Nov 07 2008
Country: USA
Contact:

Re: Are mikuni tmx35 carbs any good?

Post by Julien D »

If a 158 feels lean, you really really need to check your engine. Pretty much the only way that should happen on a stock KDX is if there's a sizable air leak. 158 was the stock main, and it was absolutely pig rich even at sea level.
Image
User avatar
Actionman
Supporting Member I
Supporting Member I
Posts: 621
Joined: 09:08 pm May 22 2013
Country:
Location: Parts unknown

Are mikuni tmx35 carbs any good?

Post by Actionman »

I'm sorry, I meant a 155 "felt" lean. If I tried to full throttle in top gear, it would stumble and bog, but if I let off the throttle a notch it would run faster. It may have actually been rich but the popping made me think it was lean. Mine had a 160 main and 48 pilot when I got it btw.
2002 KDX 200
Post Reply