Mikuni TM40 tweakin

[6fidy]

Hi all,

A little question for the Mik TM40 guys, I have noticed on my R since I put on the TM40, that it seems I require more rotation of the throttle to get to fully open, not that I get to enjoy the experience that often:smirk:

It's not a real lot more, the old carb was easy to get to wide open where as the new one requires a bit more rotation of the throttle.

Did anyone else notice it and come up with a solution? I considered taking the wheel of the old carb where the cables connects to and fit it to the TM40 but I am about to list the old carb on Ebay and didn't want to dud the buyer with an incomplete carb.

[valvesrule]

Try a different throttle assembly. Don't know what you have now but my TM based carb is fine.

[6fidy]

Try a different throttle assembly. Don't know what you have now but my TM based carb is fine.

Thanks, but can you be more specific? I live a long way from my nearest bike dismantler and it could be a long drawn out process getting the right one. Considering the plethora of different bikes out there it would be like searching for a needle in a hay stack.

[BADCOOKY]

Yea 6fiddy it's because of the bigger wheel on the carb mate.

I actually like it cause i can meter in how much i want easier instead of it just going mental..

Let us know your findings.

[6fidy]

Thanks.

It's not a real bug bear of mine so I won't be that disappointed if I don't correct it just prefered the old carbs throttle action, but not performance:lol:

Just that the R is in a hundred pieces at the moment and I'm looking at a few things before I put it back together and go to the dyno.

Header thread coming up..

[MAZMAN]

I would imagine you would need a different throttle tube, one that has a bigger diameter lobe where the accelerator cable wraps around to.

Saying that, i dont know which tube you would need!

Unless you had a bunch from different bikes and able to look at them, it would be hard to just guess, so hopefully someone here has done it and can give you some advise.

Ill be installing mine very soon so i may want to to the same thing, if i dont like it, so id like to know the results of others as well.

[6fidy]

Yeah, if you look at the wheel where the cable attach's to on the standard carb, it's more of a cam type shape where as the Mik is a true circle.

It's just when your ringing it's neck on that big long straight to see what she's got, I find the standard fitting onto the Mik means you have to twist it just a little bit more than with the standard carb, not a big problem at all, just looking for a tweak.

[BADCOOKY]

You can buy a throttle tube with changeable ratio for a short pull throttle,i seen 'em when i worked at Honda.

They're way overpriced but it beats making something or but/if you do make something make 2 champ.

[6fidy]

Wow Wesk, you just cracked 1500 posts.

Hardcore man.

[jokerflingo]

Wow Wesk, you just cracked 1500 posts.

Hardcore man.?

Hes my idol

[BADCOOKY]

Wow Wesk, you just cracked 1500 posts.

Hardcore man.

Apparently i've just gone platinum!

[jokerflingo]

Alright guys, carby came in the mail yestee, fitted it up today all went well and good, i believe the settings are

MJ = #145

PJ = #22.5

AJ = 1.2

JN = Y01

NJ = Y-4

AP nozzle = #45

I bolted it on today started her up and adjusted the fuel screw a bit so it would idle and the idle screw up a bit.

Then put it back together for a test ride and it was a bit hard to start with or without choke but i got her started.

Will try testing again tomorrow but thought i would post incase anyone has any pointers?

I think the fuel screw is around 2 turns out. Took it for a spin round the block and it pulls extremely hard flat out and doesn't seem to have any noticeable bog.

I havnt adjusted the AP for anything else yet, still got read the instructions and any tips you guys have.

Any help is extremely appreciated.

Piccy too

Thanks

Matt.

[BWB63]

I like those settings but, the main jet seems a little large. 137.5 or 140 seemed to work best for me but, I am at 2800' asl.

[tiemann1]

Alright guys, carby came in the mail yestee, fitted it up today all went well and good, i believe the settings are

MJ = #145

PJ = #22.5

AJ = 1.2

JN = Y01

NJ = Y-4

AP nozzle = #45

I bolted it on today started her up and adjusted the fuel screw a bit so it would idle and the idle screw up a bit.

Then put it back together for a test ride and it was a bit hard to start with or without choke but i got her started.

Will try testing again tomorrow but thought i would post incase anyone has any pointers?

I think the fuel screw is around 2 turns out. Took it for a spin round the block and it pulls extremely hard flat out and doesn't seem to have any noticeable bog.

I havnt adjusted the AP for anything else yet, still got read the instructions and any tips you guys have.

Any help is extremely appreciated.

Piccy too

Thanks

Matt.

Curious, your altitude and clip position on needle??

[jokerflingo]

I like those settings but, the main jet seems a little large. 137.5 or 140 seemed to work best for me but, I am at 2800' asl.

Curious, your altitude and clip position on needle??

OMG i cant believe i forgot my altitude etc rofl.

I am would be pretty much at sea level most of the time and the clip position i would be in the stock position from factory.

Can i ask if you guys use the choke everytime when starting as with the stock carby?

Thanks

Matt.

[6fidy]

OMG i cant believe i forgot my altitude etc rofl.

I am would be pretty much at sea level most of the time and the clip position i would be in the stock position from factory.

Can i ask if you guys use the choke everytime when starting as with the stock carby?

Thanks

Matt.

If cold, yes I do but with the pumper a couple of squirts richens it up OK. As someone once posted up here, the XR's are warm blooded and need that warm up before they run right. I always start with the choke and ride off for a couple of minutes before knocking off the choke. One advantage of that long choke cable is I can just reach down to the cable and push in the choke without having stop.

Sorry I can't help with the carb tuning, I am a self confessed dumb arse when it comes to tuning carbs:smirk:

I can run a billion dollar refinery but be clue-less with carbs:banghead:

[jokerflingo]

If cold, yes I do but with the pumper a couple of squirts richens it up OK. As someone once posted up here, the XR's are warm blooded and need that warm up before they run right. I always start with the choke and ride off for a couple of minutes before knocking off the choke. One advantage of that long choke cable is I can just reach down to the cable and push in the choke without having stop.

Sorry I can't help with the carb tuning, I am a self confessed dumb arse when it comes to tuning carbs:smirk:

I can run a billion dollar refinery but be clue-less with carbs:banghead:

Thanks for the reply, will try some more techniques tomorrow, keen for some more info on the refinery u own too ?

[BADCOOKY]

Mixture screw might be in a bit,might explain the hard starting.

2 turns out and hard to start with a 22.5 sounds a little lean.

[6fidy]

Thanks for the reply, will try some more techniques tomorrow, keen for some more info on the refinery u own too

Err, I don't own it, I just work there in a senior operator capacity.?

[jokerflingo]

Mixture screw might be in a bit,might explain the hard starting.

2 turns out and hard to start with a 22.5 sounds a little lean.

It came with an extra 25 pilot too, worth a shot you reckon?