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3rd Gen Carb Jet Sizes


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  • Member Contributer

Hi All,

 

    About to rip into the 3rd Gen as the carbs are leaking so bad, I'm afraid when the furnace lights up, the whole garage will go with it! I have the Factory Racing jet kit in the bike, but do not know what the correct jets, and needle position are for the two brothers header and pipe. The bike ran like a banshee up top, but when cruising around, if I would get back on the gas, or try to rev match, there would be nothing there. Also it would surge while cruising steady-state, don't know if it was rich or lean. It did idle fine and start every time. I think it may be the tiny screws at the base of the carbs? Sorry, not a carb wizard, but I know some of you are.

 

A while back someone posted the original carb tuning paper that came with the kit, but for the life of me, I cannot find it. Also bought the Litetek kit, and have no idea where those o-rings go.....help?

 

Thanks!

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  • Member Contributer

Ahhh, that's what I wanted! I think it just needs the carb synch, and fuel screws adjusted, after replacing all the gaskets/o-rings.

 

Thanks JZH!

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  • 5 months later...
  • Member Contributer

Ok, so I have the lite-tek kit and a new fuel pump as the old one was leaking from the electrical connector. Bought all new float valves and seats, floats look ok. Carbs are all separated, and one of them is apart. Here is what I found:

 

Main Jet: 135

Pilot Jet: 38

Needle: #3

Fuel Screws:  2 and a half turns out

Two Bros header and pipe

Factory Ignition Advancer

K&N Air Filter

 

The bike ran like a banshee up top, and would pull hard at any rpm, but when cruising around, if I would get back on the gas, or try to rev match, there would be nothing there. Also it would surge while cruising steady-state, don't know if it was rich or lean. It did idle fine and start every time.

 

Looks like the Factory racing set up sheet has everyone using a 40 pilot jet, but none are CA bikes. Is the 38 pilot for CA cams, or same cams, just lean pilot for emissions?

 

Can the fuel screws correct the surging and off/on gas issue?

 

Anyone have the "Common Service Manual" that explains the float height adjustment?

 

 

Thanks!

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  • Member Contributer

I don't have a Factory Service manual, but I've taken a pic of the adjustment procedure from my Clymers. Hopefully this will get you started.

 

I've left the pic as is because rotating it 90 degrees crops it.

 

 

DSCF3321.JPG

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  • Member Contributer

Forgot to mention then float height is 9.0mm on the 3rd Gens.

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  • Member Contributer
5 hours ago, FromMaine said:

I don't have a Factory Service manual, but I've taken a pic of the adjustment procedure from my Clymers. Hopefully this will get you started.

 

I've left the pic as is because rotating it 90 degrees crops it.

 

 

DSCF3321.JPG

Show Fig. 28 please.....

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  • Member Contributer
4 hours ago, FromMaine said:

Forgot to mention then float height is 9.0mm on the 3rd Gens.

Is there a +/- tolerance?

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  • Member Contributer
2 hours ago, squirrelman said:

surging is usually a lean indication,  so try opening up the idle mix screws about 1/2 turn or try #40 pilot jets.

Thanks Squirrelman, I will be ordering the #40 jets...........

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On 7/27/2018 at 8:14 PM, RC1237V said:

Is there a +/- tolerance?

 

it's not a very precise setting as eyesight, judgement, and measuring errors all factors in, so tolerance runs about 1/2 mm either way.

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Is it ok to not put the caps back on the ide screws, or will they creep out of adjustment over time?

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  • 1 month later...
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About to re-assemble, but the Lite Tek kit came with O-ring #006 (2x9.5x13) and O-ring #012 (2x9x13). It seems like one set will be extra? I cannot tell which set goes on the air tubes as the old O-rings are so shrunken, that they do not measure anywhere near the size of the new parts. Anyone know which is correct, and where do the 4 remaining O-rings go?

 

Also, is there any carb assembly lube, or just put them on dry?

 

Thanks in advance for any help!

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6 hours ago, RC1237V said:

 

Also, is there any carb assembly lube, or just put them on dry?

 

Thanks in advance for any help!

I lube the moving parts with WD40 spray and use silicone grease on the isolators to help get a seal. If the rubber isolators (boots) are old and hard it might be worth replacing them or warming them up a bit before installation, this will make the fitment easier. It's important to make sure the rubber isolators are not damaged and are correctly fitted between the cylinder heads and carb bodies (no vacuum leaks).

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  • 1 month later...

I have a set of gen3 carbs for sale, freshly cleaned, new fuel tube O-rings, adjusted, synched, leak-tested and ready to go.  no fuel in them since rebuild.

 

questions ?:  squirrelmanxxjerry@outlook.com

 

oct_15---18_018.thumb.JPG.d3f049a90d85aa1b08d64f6685bce3ba.JPG

 

 

 

 

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I will keep that in mind, as I think I have a bad diaphragm. Any sources other than used carbs?

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