Author Topic: Carb choice Duncan PJ35mm or PWK38mm (Read 1030 times)

Sparky · « **on:** February 06, 2014, 08:26:37 am »

My question for all of you super Mod minded. I have a 1986 LT250r, just rebuilt with a wiseco piston, FMF full Fatty exhaust, UNI filter.
I picked up two carbs on eBay. A Duncan Racing PJ 35mm and a PWK 38mm. I only bought both because of the prices.
So which is better for my setup? I ride pretty hard in all areas but I don't drag race. I want one that is reliable and predictable?? And does anyone have experience with either? And what are good baseline jetting setups for both?
Thanks for all of the help.

CorrecCraftFanatic82 · « **Reply #1 on:** February 06, 2014, 09:27:01 am »

Is your head modded?? If so u can use the 38 pwk, the pj series sucks! I had one , if your head is stock use the 35pj , it will give u good bottom end , these motors 85-86 are half piston port an reed caged, aka bastard child design. I personally went from a stock motor an carb to a duncan power head an 36 pj fmf pipe to same head with different dome an a flowed 36 pwk = 37 , ported cylinder an in frame mhr pipe , that pj was a piece of turd , when I put my pwk on,what a huge power difference, it all depends on ur motor mods . Or just try each of them.

Sparky · « **Reply #2 on:** February 06, 2014, 09:35:55 am »

No head work on mine. If I could find one I would buy it.
Was the PJ hard to tune or just a poor design?

CorrecCraftFanatic82 · « **Reply #3 on:** February 06, 2014, 09:37:34 am »

As for your jetting call up Loren at duncan racing he's very helpful , he will set u up with what u need, he will ask u what needle an jets are in both carbs , the jet/needle kits are fairly cheep , or call sudco racing they too can help you.

CorrecCraftFanatic82 · « **Reply #4 on:** February 06, 2014, 09:39:13 am »

No pj is ok.... Its more of a bottom end carb.... Pwk series are much better! Better bottom to top end

CorrecCraftFanatic82 · « **Reply #5 on:** February 06, 2014, 09:40:09 am »

Yes the pwk series are easy to tune than the pj

Sparky · « **Reply #6 on:** February 06, 2014, 09:50:05 am »

Is the 38mm PWK to big of a carb for my setup?

CorrecCraftFanatic82 · « **Reply #7 on:** February 06, 2014, 09:51:44 am »

Typically when u raise up carb mm's up you need to lower your head cc's to raise cranking pressure, remember ever cc is 10 pounds ( psi) , if I was you , send your head out an have it cut, squish band correction, u will feel the difference, try Dennis at flotek performance , he's great to deal with. You can go with a duncan power head but it costs abt 250 , 100.00 just for the dome, special size.., so send stock head out. Just my .02 .

Q2W · « **Reply #8 on:** February 06, 2014, 09:52:17 am »

I'd sell them both for a profit and get an 88+ zilla carb 38mm mikuni. Pretty sure you can pick one up for under $100. You can fine tune mikuni's much better than any pwk. just my

.

CorrecCraftFanatic82 · « **Reply #9 on:** February 06, 2014, 09:56:19 am »

Yes I think as rite now , that pwk is a lil big for ur set up, send ur head out an then use the 38 pwk an u will be glad u did!

LT250RWV · « **Reply #10 on:** February 06, 2014, 10:31:50 am »

I agree with Q2w . I tried pj 38 then pwk 38 now I have tm 38mm zilla carb. Only took me a hour to get way 10 or 15 hour of tunning pwk. But if you need jets and needles for pwk I have a bunch of them forsale.

Sparky · « **Reply #11 on:** February 06, 2014, 10:37:26 am »

I emailed Flotek to see if they can help.
Pm me on the jets. Never hurts to have them around.
I wish I had the 1987 up engine, there are far more upgrades for them.
Does anyone have any other performance parts for them? For sale?

CorrecCraftFanatic82 · « **Reply #12 on:** February 06, 2014, 12:43:54 pm »

Yeah there's not much aftermarket or performance parts for the 85-86, good pipe , porting , try tony ducas racing reeds, they offer two styles, standard an carbon fiber , get the carbon fiber, u can find them at jl atv products .com , if I'm correct I remember there was a company out here in Cali called 1dirracing they mad a billet reed cage for our bikes, I have one an It did great an still have it on motor. Had bike on a dyno abt two years ago it added 2 hp on my 86, with my set up I'm at 36 hp , stock was like 18 - 19 I believe ...

LT250RWV · « **Reply #13 on:** February 06, 2014, 01:47:43 pm »

I think they were in high 20s

CorrecCraftFanatic82 · « **Reply #14 on:** February 06, 2014, 02:36:21 pm »

Maybe 22??

LT500Kid · « **Reply #15 on:** February 06, 2014, 04:03:52 pm »

Hard to find a 88+ carb for less than 100.

LT250RWV · « **Reply #16 on:** February 06, 2014, 06:58:34 pm »

I just bought a new tm 38 for 170 $.

Sparky · « **Reply #17 on:** February 06, 2014, 09:01:31 pm »

Thanks for all of the info guys!

PCS · « **Reply #18 on:** February 07, 2014, 05:05:14 pm »

funny that over on a the 3ww website most seem to hate the tm and swap them out for pwk...

1986QuadRacer · « **Reply #19 on:** February 08, 2014, 08:52:51 am »

Mikuni

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Author Topic: Carb choice Duncan PJ35mm or PWK38mm (Read 1030 times)

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