I know what your talking about with the "drop out". Get on the throttle hard, back off, then get back on it - it takes amoment for the engine to clear out and rev. Mine was doing it too, but I thought at the time thatan accelerator pump adjustment would clear it up. It didn't. I went to a 9EBY1-50 needle instead. Both the 9EBY1-50 and 51 needles are leaner than stock. Of the 2,the 50is the leanest and the 51 is a bit richer. Some guys run 17.5or 20 pilot jets with these needles, but a 15 is working well for me.

Theseneedleshavea different taper than stock. The end result is this; The 9EBY1-50 needle helps throttle response and helps clear up the mid-ranged off/on throttle stumble. By itself though, the needle change didn't eliminate the stumble completely. It's still there, butmuch, muchbetter than with the stock needle. It's completely rideable as-is, but next, I think I'll trya P-6 needle jetto get mewhere I want to be.

Anyway, here's my current setup:
-340cc kit
-Supertrapp muffler/full exhaust
-K&N filter, airbox lid removed, backfire screen removed
-Mikuni TM36-68:
-130 Main Jet
-15 Pilot Jet
-9EBY1-50 Needle - Clip 3rd slot from top
-P-8 Needle Jet

 

I ordered the alternate needles and needle jets. Getting the TM36 tuned is probably going to end up being a winter project.

From what I could find, a common setup is using the P-4 needle jet with the 9EBY1-50 needle. But this was for a 400cc displacement.

Snow was flying after our ride yesterday as we came back over Trail Ridge Road (US34) through Rocky Mountain National Park.

 

sorry for whoring you guys's post.....we couple had a momentary lapes of thought as the 2 stroke thing totally took over us in the memory department.but yeah i have to reply to them.....[&:]
Kudos to you for getting the chance to ride what we would never see in America......My true dream bike is a Kenny Roberts RZ-750 2-stroke 4 cylinder......Unfortunatley most of them were totalled or scrapped.....If they banned the bike from racing 95% of all classes in AMA sanctioned events that says something for horsepower.Last i checked A bone stock one with jetting,pipes and reeds would discharge a little over 200 hp. at the rear wheel.......would be a really fun straight line machine if built right...
sorry for soiling your post guys......

 

No riding this weekend or last, so I decided to try and get the TM36-68 working.

Again, what a nice carb to work on, so many adjustments available and easy to get in and out of the bike. I have a Clarke tank and there is a fitment issue. Time spent with a dremel tool cutting off and grinding down part of the bell crank and part of the bracket took care of this.

Started out with Mustang's setup (thanks Mike):

MJ: 130
PJ: 17.5
Needle: 9EBY1-50 middle clip
Needle jet: P-4

...and my conditions:

Alt: 5000'
Exhaust: full Muzzy
Intake: K&N - airbox lid on, snorkle removed and extra cutout
Displacement: 331cc

Wow! ...very nice. A wee bit of a bog @ W.O.T. - (will try either airbox lid off or go down to a 127.5 MJ - maybe I'll put in the 127.5 for good measure anyway due to the altitudes that I ride at in the summer). There's a bit of a lag on the accelerator pump kicking in coming off closed throttle (I'll play with the adjustment). Throttle response is snappy, especially with the Vortex -- no clutching necessary to pop up the front in 1st or 2nd. Smooth strong power to redline.

Best idle around 1350 with two turns out on screw - I do get both the lean and rich stutters while adjusting the screw.

Just a bit more tweaking and it'll be perfect. Need to do some plug readings - I'm guessing I'm a bit rich - but I have found that this bike really likes the rich side of things.

The cutout upon closing the throttle is gone!

 

See, I told you so. I'm glad I could help. I'm not running the lid on my airbox - actually, I never tried it with the TM36. At 2400' ASL, the 130 main works great for me, but at your elevation, you're probably right about the 127.5 main jet.

The TM36 does like being a bit on the rich side, and it really is nice to work on. Once I figured out what does what on the carb, it's actually pretty easy to set up. Getting to that point was a little bit of work though.

Take a Phillips screwdriver with you out on a ride. Back off the A/P start screw a turn at a time until you get a rich low-end bog. Then turn the screw inby 1/2- or 1/4-turn increments until the bog goes away and you get your best throttle response. On cold days, I've found thatdelaying the A/P start just a little bit more than usual works well.

Also, make sure the A/P squirter is pointed directly at the needle. When the A/P squirts, fuel should actually splash off the needle. Mine didn't do this initially, and adjusting the A/P timing didn't seem to makea lot ofdifference. After reading the Mikuni tuning manual, I repositioned the squirter. A/P timing adjustments actually didsomething then and throttle response was even snappier.

 

Here's a picture to clarify the surgery for getting the TM36-68 to fit with the clarke tank. ...and mustang's original photo for comparison.

 

You did a nice job on the bracket, but I have to ask why? The throttle wheel of my carb justrubbed theinside of the sump on the Clarke tank, so it hand to be ground down, but the throttle cable bracket cleared by a bunch. Your bracket looks nicer, but I didn't have to cut mine to get the tank to fit. I wonder if my Clarke tank is somehow different from everyone elses.

 

Thanks. The tank seemed to be reseting on the bracket as well as the bell crank rubbing. However the top cap on the carb seemed to have clearance. Rather than going back and forth with the fitting, I just decided to take off as much and I could and get everything lower than the top cap.

The picture is a little deceiving, although it appears that the bracket and crank is higher than the cap, they are not. The cap is slightly higher.

I doubt your tank is different.


I'm talking about the bracket behind the crank (in parallel with it). Are you referring to the part of the bracket where the unused pull-closed cable threads through? If so, then you are correct, this didn't need to be cut off. I figured with the part of the crank gone where this should go, it served no purpose and cleaned things up.

 

I understand now. I didn't even look behind the throttle wheel at first - I just saw that you cut thereturn throttle cable bracket off. But still, my bracketclears everything...

Did you finish getting your carb dialed-in yet?

 

Not quite finished yet -- but it's staying on. Current jetting is good enough to ride with (the needle jet/jet needle change did it). Pulled it last night to check and reposition the pump jet and put in the 127.5 MJ in. No test drive yet, it's snowing today.

Cleaned up the Bill Blue TM34 and am thinking about ebay'ing it once I get the current jetting on the TM36 completely checked out.