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Joined
11/25/2007
Location
Athens, GA, USA
Edited Date/Time
9/1/2026 8:52am
Need a Keihin jet block gasket for my project, but I've been reading that even some brand-new ones are showing up flattened or with other imperfections.
Has anyone found a good source for quality Keihin jet block gaskets? Ideally something from a different manufacturer than the commonly available ones that seem to have these issues.
I'm happy to pay a premium for a genuinely better part, but I'd rather not just pay more for the same gasket with nicer packaging or marketing.
Would appreciate any recommendations from people who've actually used them.
JD Jetting has always been a good source for me.
JD makes a better replacement block gasket.
What they said.
JD jetting has a Mikuni jet block gasket that's better than stock.
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Do they have this for Keihin or just Mikuni?
https://jdjetting.com/product-category/carburetor-parts/2-stroke-carburetor-parts/
Yes
I checked JD Jetting, but I couldn't find anything on their site confirming whether their gasket is a genuine Keihin part, and it is currently out of stock anyway. They could be sourcing their jet block gaskets from the same Chinese factory that pumps out all the rest (which have common defects)
I was able to find the original Keihin part number, which is 1202-834-2000. I'm trying locate an active Keihin dealer who can order individual parts for older carbs. I found KM Carburetor in Michigan, but haven't been able to get in touch with them yet.
If you are in Europe it looks like Franks has it, but Franks does not ship to the US.
James Dean's gasket is not the same as OEM.
I assume you are having the same issue as i did on my 2009 150SX with the Keihen. Tried everything , but the gasket, and still had issues on top end with not wanting to rev. Got the JD jet block gasket and it was perfect immediately after that. Their stuff is usually reliable. I had a PWK38 on mine. It is in and out of stock.
OEM is Japanese and high quality. If I could get the Keihin OEM Japanese part I'd pay a premium for it.
The OEM is what everyone is replacing with the JD part, because of its high rate of failure.
20-30 years of service life is hardly a high failure rate.
The $15 made-in-China options all over eBay and Amazon are well known for arriving with defects - sometimes broken while still sealed in the package, sometimes with too little gasket material to seal properly, and sometimes simply malformed from the factory.
If you want the good OEM stuff, there's a place in Cleveland called www.jetsrus.com that has them. I used them for everything.
I use Niche Cycle for all my Keihin and Mikuni OEM needs.
I can't be the only one that really misses Sudco. They had every Keihin part imaginable and some you would have never thought of.
JD Jet is about the only place you can even get a full Keihen carb. Just replaced my POS Mikuni on my 2017 250SX with a new Keihen about a month ago. Best upgrade ive done to it so far.
The site I listed has all their shit.
And to provide clarity, the particular part the OP is looking for isn't listed on standard parts fiches.
Theyre also the only place that has the nozzles for rhe TMX mikunis so you can drop from an S9 to an S8 and stop swapping the whole carb out for a keihin. The TMX is better.
Pit Row
Some good news from Kurt at KM Carburetors:
location: Clinton Township, MI, United States, 48038
site: kmcarburetor.com (they don't list jet block gaskets here fyi, gotta contact them direct)
insta: km_carburetor
phone: (313) 590-8086
email: sales@kmcarburetor.com
I still think you're better off getting the JD jet block. There are a LOT of Keihin KTM users that would agree with me.
I've already ordered the KM Carburetor genuine Keihin jet block o-ring (two of them one for spare).
Earlier you said that JD Jetting was better than OEM, but I just called JD Jetting and they confirmed that the jet block o-ring they sell is also OEM (Keihin). I wish they'd include that in their listing, but anyway - they are out of stock and KM Carburetor has them right now.
The JD replacement I put in my YZ125 was not the same as the OEM I took out. I supposed it's possible the OEM was updated since.
OEM and JD Jetting are exactly the same (Keihin) is the point I'm not driving home very well. Keihin is the supplier for your original YZ125 (unless you bought used and someone else put who knows what in it). It's what JD Jetting and KM Carburetor sell as far as jet block gaskets go.
If you bought new and Keihin updated the part, that's good news since they are actively developing that product.
I'm just happy we figured this out!
Yz125 is a Mikuni and the jd kit replaces the oring with a coated metal gasket (source is my yz125).
There was a lot of talk about this at KTMTalk a year or so ago, with James Dean chiming in. I’m certain he stated the gaskets he has are made by Cometic for him, with a metal core and rubberized outer.
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