in trying to correct the jetting, I dropped down from 17.5 to a 15 pilot, tried both a .9 and a .8 pilot air jet and the the rpms will hand at 3500 for multiple seconds (upwards of 5 or so) before slowly coming back down. This is only if I rev the bike to this point, if I dont rev so high its just fine. Pull the choke out and it'll drop right down.

Lean pilot jet maybe?

 

added the 17.5 pilot jet back in, still hanging at 3500rpm. What gives....

 

stuck needle or diaphragm?

 

First thought would be an air leak. Did this happen the first time you installed the carb, or did it start during the jetting process? I don't think you should get that with any of the combinations you mention.

Edit: I guess you're pulling the carb each time or tilting it at least. Is a cable dragging or such?

 

Make sure your intake manifold clamp is tight enough.

The slide return spring is so strong I don't see how the slide itself could be hanging up

 

Fiddled with it some more and couldn't figure it out. I took it for a ride to see if I could figure it out, throttle is sticking. Not the cable, the carb itself. I'm not sure how the slide could be sticking. But it almost seems like the vacuum from the engine is causing it to stick a bit at the end of the stroke.

 

I'm guessing you're aware that the throttle wheel tension has 3 spring positions on the carb? Still, hard to believe the slide is sticking internally or via the linkage on a newer carb...unless something external is sticking. What gas tank are you running?

 

What happens if you take the tank off and rev it by twisting the throttle wheel by hand? It's pretty much mechanically impossible for the slide to stick if the throttle wheel is returning to idle position.

- Unless the rocker arm thing under the carb lid has somehow come loose or disconnected from its shaft. Take the lid off the carb and watch what happens as you cycle the carb open and shut either with the engine running or not.

If you have a larger gas tank on your bike the upper part of the throttle wheel will rub on it

 

Its the stock tank, nothing rubbing I'm sure but ill double check it. I recall thinking it was a little sticky initially turning the throttle wheel by hand. Haven't a clue why, maybe a little dirt got in there?

In other news, .9 air jet, 15 pilot, p6 nj and y1-51 needle 3rd position is close. Still a little rough at initial throttle but otherwise not bad. Ill drop the .8 air jet in to see if that helps.

 

I had the same problem.

Double check the cable routing, make sure there is enough slack. You want the bends to be as loose/wide as possible. Tight bends cause drag.

Another problem is the seal to the intake boot.

If you look at the TM carb next to the stocker you'll see there the end of the mouth that connects to the intake boot is chamfered, that is there is a bevel there. Slightly further back the carb has a groove cut into it to accept a lip that slots onto it to help seal the carb. Feel around inside the intake boot, you'll clearly feel these.

It was my experience that the intake boot stood off the TM36 when it was inserted into the boot. The TM never seated right.

I guess you could simply squash it down, but we put the carb on a lathe and machined it to fit.

An air leak on the intake side will cause the bike to run on as air for the engine to compress is still being pulled in, and there is enough residual gas coming from the carb for the bike to run very lean, but still run after the throttle is closed. You can test this by shooting a little carb cleaner on the suspected leak area as it slowly returns to idle. If there is a leak there it'll rev back up as the mixture become closer to correct.

Make sure you have adequate slack in your cable run, make sure the carb seats tightly into the intake.