I've taught myself a lot about slide carbs the last couple years ...learning some of their nuances and potential for throttle response and control. Finding a jet with a higher or lower number than the one you already have isn't exactly easy due to fitment issues, but jetting isn't the rocket science here. The holes are either bigger, or smaller. Jet needles on the other hand are more of a black art. Needles have fitment issues, like jets, but also taper issues, tip issues, diameter issues, clip position issues, and mid-point issues (aka: "L1"). Your average Mikuni carb can have dozens of different needle types made for it. And I've been selecting and purchasing particular needles for this one Nibbi PE24 carb I'm still tuning (which I've determined uses needles equivalent to the Keihin PWK28).
Still, needles are hard to research, and apparently even harder to find for sale. Try searching eBay for a certain carb's needle types and you'll generally only find a couple standard sizes by a few popular codes, ...or maybe just "needle fits VM22". That's been my experience anyway...
I found the JetsRus site to be organized and having the info one needs to navigate these matters. They have a good inventory. I've spent some money there. But alas now I'm arguing with them over a defective product they sent.
So yeah I'm getting really into needles, for Keihin PWK anyway, and as a matter of principle I have to shop for another vendor. Well last night I found Allens Performance. Their site is similarly well organized. It's also well stocked with the usual jets and other accessories, but also some pretty obscure needles even the other guy didn't have. Shipping costs seem really reasonable too. So stay tuned...
And that's all I've got for now. But chime in if you want to talk jets or needles!
Well it's been a month since I put in two orders with Allens. The $15 order arrived within 2 weeks...(a pair of grips). But the second order ($60 worth of carb needles, clips, washers and I forget what else) still isn't here. I've emailed as well as submitted messages directly thru their website, and ...crickets...(chirp chirp)..
So now I got beefs with jet & needle dealers on both sides of the Atlantic.
Would you believe I woke up to an email from them? The particular Keihin needle I wasn't happy with from jetsrus is on back order in the UK. Well at least it only took 5 weeks for their email to arrive..
@Minimichael I feel your pain! I bought jets from several aftermarket companies (non-OEM jets). As you say it's a bit of a crap shoot as to what you'll get. I measured a bunch of jets from various suppliers to compare them to OEM Mikuni's. Most of them weren't even close. Word to the wise: Stick with Mikuni jets or a single supplier or you will go insane trying to jet your carb.
While doing measurements I did find a non-OEM supplier that has jets that measure the same as the Mikuni OEM jets. I've emailed with them and they are very responsive. I asked if their jets flowed the same as OEM Mikuni's and they said YES. Confirming my measurements...They are well aware of the bad knock-off's out there. I've ordered from them 3x and typically have the parts in 7-9 days. I believe they are based in Hong Kong. They are listed on Ebay. The name of the company is autopower_us. Do a search on Ebay for autopower_us and they'll come up. They guarantee satisfaction and allow free returns. Prices are very low for Mikuni non-OEM jet kits. Well worth exploring if you want to save some $$. If you buy from them let us know how you make out.