Does anybody make new carb needles?

[nzspokes]

I think Im asking for something thats not a thing. Anybody in NZ make carb needles?

No I cant just go buy one as nobody makes what I want.

[SaferRides]

Maybe not in Auckland but I'm sure someone out there makes them as there are still carb jet kits for sale.

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[Grumph]

Making a needle isn't difficult. Any precision engineer could do it. What's hard is getting the right taper. Do you have a damaged one to copy ?

[nzspokes]

Making a needle isn't difficult. Any precision engineer could do it. What's hard is getting the right taper. Do you have a damaged one to copy ?

If I can find somebody to do it I would just buy one and tell them how I want it different. Leanest one available is still too rich.

[F5 Dave]

Probably because your needle jet has ovalised and is letting wet fuel through front and back. Bright light and magnifier will show that.

Tell us the carb.

Not uncommon for vibration to kill some. Factorypro sell emulsion tubes for certain models. I made some replacement needle jets for my RF900 tubes and superglued them into bored tubes as they wore every 10000. Nowadays I would have reprinted the plastic slide runners that had worn.

[nzspokes]

Probably because your needle jet has ovalised and is letting wet fuel through front and back. Bright light and magnifier will show that.

Tell us the carb.

Not uncommon for vibration to kill some. Factorypro sell emulsion tubes for certain models. I made some replacement needle jets for my RF900 tubes and superglued them into bored tubes as they wore every 10000. Nowadays I would have reprinted the plastic slide runners that had worn.Carb is a TM42 with 15,000ks on it.

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[F5 Dave]

Ahh, so bolted to big 4 stroke single or Hardley. Either will vibrate. But removable emulsion tube, so inspect it carefully and replace as required. There might even be smaller options. But any ovality will make it unjettable.

[george formby]

Ahh, so bolted to big 4 stroke single or Hardley. Either will vibrate. But removable emulsion tube, so inspect it carefully and replace as required. There might even be smaller options. But any ovality will make it unjettable.

Ahh, teh mulching tubes. My TDM eats them. Smell of petrol and the odd back fart, time for new tubes..

[Grumph]

They don't make brass like they used to. Tempted at times to make up needle jets in steel - and hard chrome the needles.

[nzspokes]

This is all a good point. I will check the needle jet out. Didn't think it was old enough to be a problem.

Its on a DR650.

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[husaberg]

Ya lucky as they are replaceable on the Mikuni.
much cheaper than a custom needle
but it does raise the question if it was correctly jetted before with the same jet and needle combo before it has to be wear rather then a needle not lean enough.
i have a model makers lathe i have seen them made and modified on them.
But tbh if you had to make one, some sandpaper ,A ruler, a drill, a Vernier and Mondo patience would suffice, but making two would be very hard.

[Grumph]

Just takes twice as long. Actually modifying needles for a set of 4 carbs takes less than 4X as you're repeating diameters at fixed points. Then blending.

Ah, the joyous days of modifying carbs for exotic fuels....

[nzspokes]

Pulled it out and it looks fine. Not oval at all.

But its a huge hole. I can see why its so rich.

Its got the leanest one in as well. I cant find the spec for the jet, I could measure it.

[Grumph]

New one from Mikuni Oz won't cost a lot. Worth getting IMO.

If what's in there now measures up as bigger than 3mm it's either worn or modified.

[F5 Dave]

Presumably 15,000km ago it ran better? Lest I doubt 15000km would have been successfully negotiated, or at least the first 1/2 of them.

[nzspokes]

Its always been too rich. But got worse with the change to a chambered muffler to prevent going deaf.

Will measure the needle jet to see the difference between that and the needle. It seems like a huge gap.

But these carbs were designed for harleys.

[F5 Dave]

Must be a super common DR mod? What are others running?

As said before (if you can't get a smaller jet) you could get a toolmaker to machine a peice in the centre and then an insert say 5mm tall slightly smaller hole.

Superglue it in. Flames will then drop it out if you want to try another size. Just be sure there are no sharp edges.

[husaberg]

Its always been too rich. But got worse with the change to a chambered muffler to prevent going deaf.

Will measure the needle jet to see the difference between that and the needle. It seems like a huge gap.

But these carbs were designed for harleys.

So you currently have a 784-430000-Y2 Needle JEt?
this is the leanest Needle Jet i can see.
and you are using a Needle with J8 DDY01-98 Needle
this is the leanest stock Needle. i can see

You have the needle placed in the groove nearest the top?

you have the float level to 18mm
352749

the choke has freeboard so is totally closing.


If you have these in place and in new condition i would then use the air correction circuits to lean it out .
Or open up the airbox which i assume you have already done? if you haven't there is your answer.


For this Mikuni carburetor to operate correctly the motorcycles air box must be opened up to allow more air flow in. Using a hole saw, a 45mm diameter hole will be a sufficient starting point where alternating between WOT runs with and without the filter access door removed will confirm if you have removed enough material. The kit also comes with throttle cables and a 1/4 turn quick action throttle.
This is the official rebuild kit for a TM on your particular bike.
https://mikunioz.com/shop/tm42-6-tuner-kits-for-4-stroke-engines/?v=13b249c5dfa9

[nzspokes]

Must be a super common DR mod? What are others running?

As said before (if you can't get a smaller jet) you could get a toolmaker to machine a peice in the centre and then an insert say 5mm tall slightly smaller hole.

Superglue it in. Flames will then drop it out if you want to try another size. Just be sure there are no sharp edges.

I had been thinking about that. Superglue holds up ok with fuel?


So you currently have a 784-430000-Y2 Needle JEt?
this is the leanest Needle Jet i can see.
and you are using a Needle with J8 DDY01-98 Needle
this is the leanest stock Needle. i can see

You have the needle placed in the groove nearest the top?

you have the float level to 18mm
352749

the choke has freeboard so is totally closing.


If you have these in place and in new condition i would then use the air correction circuits to lean it out .
Or open up the airbox which i assume you have already done? if you haven't there is your answer.


This is the official rebuild kit for a TM on your particular bike.
https://mikunioz.com/shop/tm42-6-tuner-kits-for-4-stroke-engines/?v=13b249c5dfa9

Have been speaking to the Mikunioz guys. Yes Y2 needle jet and 98 needle. They said to set float at 20mm to allow for rough tracks. My airbox pretty much doesnt have a top. Have tried with the airbox side cover off as well as no aircleaner.

They say the problem is me running a GSXR Ti muffler. They say thats making it rich. So a GSXR1000 flows less than a DR650?:wacko:

[Grumph]

A GSXR1000 has 4 250cc pulses in 2 revolutions . Your DR650 has one 650cc pulse in 2 revolutions.

Which is why silencers for multis can be straight through and work well - but big singles usually need silencer volume to absorb the heavy pulsing.

[F5 Dave]

Superglue worked just fine over thousands of kilometres and 4 tubes tested at a time. Did it twice.

You could tell it had worn. Started running funny, guzzling gas and would soot up plugs in two cylinders for some reason. As I said the plastic runners the slides ran on wore. Was cautious of repair as a sticking slide on a 900cc roadbike doesn't bear not considering.

[husaberg]

As dave said Dynojet and factory pro use/ recommend superglue for various kits.
If you were worried use a high end version from loctite.

From my experience though neat Acetone or generic nail polish remover unbonds superglue quite well.

[F5 Dave]

And the flames of a venful God. I mean keeping in the spirt of the weekend. He must be a bit pissed we murdered his (illegitimate,) son.

That'd why we have income tax and speeding fines.

But a little MAP gas torch works just as well. And you can pretend you are smiting sinners. Brass sinners.