jets for tk carbs?

Sorry, mine are tk-22's, but I believe the mains would swap. I know the idle jets are slightly different.

The plain LTD (C) uses the TK-22 (along with the D gpz and most of the A standards). The F spectre, M shaft, H gpz, and ZX gpz all use some variation of the larger CV tk's. (I think the latest standard (A4) also uses the cv version.)

Post edited by: loudhvx, at: 2007/04/15 14:44

Whoooooa... wg suggests what? Hmmm let me be specific...

Some carb assemblies are fairly rich from the factory and some are lean. Rejet depends on where a specific assembly sits on that line.

For instance. VM26. Question will be, I got pods/4 into 1... how do I rejet?

Well, the 76 KZ900 VM26 had #115 mains, #17.5 pilots, 0-6 needle jet, 5DL31-3 jet needle and 1.5 slide cutaway.

Compare to the KZ1000A2A 78 1/2 VM26... essentially the same carb but with pilot fuel mix screw and not the air screws on a 76 VM26. This is to allow more precise metering of the idle mixture... in other words easier to lean it out... Specs: #102.5 mains, #15 pilots, 0-3 needle jet, 5CN7-4 jet needle and 2.0 slide cutaway.

OK. Can you rejet both the same if pods/pipes are added? nope. The 76 carb assy can actually handle the pods and pies if a little larger main jet is used. #117.5 is fine. In fact, you can pull redline pretty cleanly with the stock jetting after adding pods and pipes... The 78 1/2 VM26 will choke to death if pods/pipes are added. If you add pods and pipes, and don't rejet, you can't pull 6K rpm. Why? some is the other internal stuff like the air jets for the main/pilot circuits. Some is the larger slide cut out that allows MORE air by when the slide is closed (and slower velocity too) and some is the very tapered and short jet needle used and some is the three size smaller needle jet. With this stuff going on, to rejet for pods and pipes, leave the jet needle clip alone and use #120 mains and #20 pilot. The larger pilot is to compensate for the bigger pilot air jet and larger slide cut out otherwise it will hesitate when you open the throttle.

No such thing as some standard X number of sizes bigger for jetting since there are too many variables.

For the TK carbs, check with owners who have successfully rejetted. I would say that on the TK22 mechanical slide carbs, that folks have had decent luck at about a #100 Keihin main jet. There are no pilots for the bike other than the stock size in a a rebuild kit so I would personally tend to leave them alone and shim or clip the jet needle 1mm higher to help richen the mix in the off-idle transition. I don't like to drill as I have had little success doing consistent drilling. On the CV carbs, they are more sensitive to pods and aftermarket pipes and you will need to go to around a #135 Keihin main jet to be able to pull redline cleanly. There is typically a much larger jump on jet sizes on a CV carb. If you do drill pilot jets, blow some carb cleaner through them BEFORE you drill and then after and make sure the dispersion of gas coming out the end is the SAME pattern. Pilots should have a fairly tight/clean pattern. At about 1 foot, it should spread no more than about 1 inch I guess. If you mis-drill and ruin the chamfer on the end that picks up gas, the spray will become a splatter. This is the problem with some defective pilot jets that have made it to the market in jet kits. I check all pilot jets prior to using them (NEW ONES).

Last... jet kits. What is a jet kit?

drill bit
sheet metal screw
jet needle
main jet

The 1/8" drill bit is for drilling the air relief hole on the bottom of the slide on a CV carb. The hole is about 1mm less diameter to start with and the theory is that the slides will close quicker if more air can come through the hole. Lots of Harley guys do this. I have tried it and can't tell any difference but some folks say they can. You can also use the drill bit to drill the cap over the mix screw. The screw is used to pry out the cap after you make a hole.

Main jet - they give you BIG main jets in almost every jet kit whether it is Stage 1 or Stage 3. OK, the large main jet really has not effect except to run rich on top... in other words you will waste gas at the top.

Jet needle - I have stacks of them from many different Dynajet kits. They are all the same for all VM carbs. Look at the example with the 26s I gave. The skinny and non-tapered needle they give will work differently in an 0-6 needle jet compared to a 0-3 needle jet They just make tuning tough. If you want to tune in the mid-range, use the stock jet needle and shim or reclip as the taper is suited for the needle jet and other internals (like the air jets and slide cut out).

Hope this clarifies any jetting comments I make. If I mention you should go up two jet sizes, that particular jetting advice is only good for that particular carburetor.

Okay..so after all that (thanks btw), as an owner of a set of wonderful, shiny, CV TK26s - and a 4-1 exhaust - do I have to go up? And if so, what jets fit my TK26s, cause the stealership said, 'there's only one set for those carbs', which I think is crap, but they're just running with what comes off the microfiche

Like I mentioned earlier, when I really crank it, it sounds like the bike runs rougher when I'm accelerating. Doesn't really matter what RPM, but only when it's 3/4 to WFO.

:S

THREAD HIJACK! bwhahaha

pyxen... I probably put too much in the last post. PLEASE take note of what I just cut from that post:

On the CV carbs, they are more sensitive to pods and aftermarket pipes and you will need to go to around a #135 Keihin main jet to be able to pull redline cleanly.

Awesome..thanks WG. I'll look into compatible jets. I think that the keihins will work well, based on the size that they have listed on their site.

I'll stick with normal pilots (32)..?

Oh! And what does drilling out the air relief hole do exactly? From reading around ( CV Carb info I found ), I gather that the hole is there to suck the air out of the slide chamber, creating the vacuum and raising the slide.. if the hole is larger, the air evacuates quicker, which raises the slide faster - right? I assume that there is too much of a good thing here, right? Too big of a hole, and you lose the effectiveness of the system...? So how do you know how much is enough?

Post edited by: pyxen, at: 2007/04/16 21:38

bump - isn't 135 a bit big, considering I only have a 4-1 exhaust, and no pods?

btw - I ended up going 130s instead of 135s, and I'm pretty happy with it so far!

Got great mileage on the high way, and it definitely responds well to throttle changes.