This is a question for those who have installed the Mikuni TM34 Flatslide carb....or those with more tech knowledge than me. My throttle has been fine upon startup and early into my rides, but lately it's been sticking after everything's warmed up...generally when I'm heading home. Off the highway, my throttle doesn't come down during gear shifts and hangs in the upper RPMs. I took the throttle assembly at the handlebar completely apart last week, cleaned, lubricated...but no fix. My Norton riding bud thinks my slide might be hanging up...this might be true, but I think that possibly the spring inside the carb might be getting weak. In any event, I'll be doing a carb teardown next weekend and check the internals out....anybody out there experience this? Appreciate any thoughts from my TM34 brethren?
Sticking throttle Mikuni TM34 Flatslide
- Thread starter cmessenk
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I run multiple TMs, including in multiple sets, I doubt that it is a carb problem per-se, those TMs have fairly strong return springs, yet even when cut down to ease throttle tension, I`ve never had one stick. Likely probable cause is upstream, in cable/throttle area..
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Sharp cable bend say at where the cable enters the carb top the thing to check. There is a proper bent piece that screws into the carb top if you check the Mikuni catalogue.
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I found with a VM that it helped a lot to tilt the carb to one side so that the cable didn't have to rub on the frame tube. If you tilt it a bit the cable can run along side the tube. I ran the cable straight in without one of the elbows. It did look wrong, but it was right.
Thanks for the comment, I had the 90 degree elbow intsalled when I put the carb on...but will check that along with carb body and between elbow and throttle grip...I don't think it's going to be too tough...but one never knows... :roll:Torontonian said:
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this is a drawback of the TM's as you can't fit an extra spring into them like w/ the VMs to reduce the chances of any hangups - and Mikuni dosn't make any heaverier springs (i tried sudco, thugh one may find something they don't know of any other springs) i doubt its the slide , id remove the cable and oil it thoroughly and make sure it slides easily and there are no bends in the cable ends - as mentioned where they go into the carbs is always an area of concern - i've always found that even if i can't see something apparently wrong with the cable, if i fit a new cable it works as new - also make sure the throttle is greased up lightly too
Thanks, Mike...I'll report back when I complete surgery and get to the bottom of the problem. I need to get this sorted out 'cause my old high school bud who sold me my Combat back in 1978 is heading up to my stomping grounds in two weeks on his new Ducati Panigale! The hills and twistys of central Florida are only 45 minutes north of here and we're riding together for the first time in 34 years. We'll also be trading bikes for a while during the weekend, giving him a chance to experience my approx. 50 hp ride for the chance to experience his 195 hp rocket ship. Talked on the phone with him this week to coordinate his visit...he told me he's through the break-in period and can now tag the Duc's 11,500 RPM w/o worry. I'll be posting pics after we're back.
bill said:
That thought never entered my mind, Windy...damn....hope not. I'll do the easy fix and if not solved then I'll look at a full carb cleanout....then I'll call Ashenbrener and ask him when my new tank will be ready...waiting....waiting...waiting.
I might have to have you give him a call for me and tell him to "get on the stick".
BTW...are you home yet?
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yes as bill said this is a real possibility, when you have the carb off look and see is you have an brownish gum accumulated on the slide/intake area - also if you can shine a light into the inlets on the head and see if there is any gummy shit there (taking the 2:1 manifold off makes it easy to spot)- i had this happen and a valve stuck and it pretty much screwed up a piston/top end - caswell sucks (actually all tank sealers suck) - your runing on borrowed time with ethanol and fiberglass tanks coated with anything
bill said:
I've found that using the cable from a push bike brake works great. They're stainless, thinner, and much more flexible than the motorcycle part. They come with a barrel soldered on one end that goes in the brake lever, you use that for the twistgrip. Use the existing cable housing, de-solder the tiny ferrule on the carb end of the old cable and solder it on the new. It can handle a 90deg bend easily.
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Could be a fraying inner cable . . . .
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Never underestimate the powers/wisdom of bicycle people. Just saw my buddy off on his new BMW 1200 S. 167 H.P., production. O.M.G. !
cmessenk said:
Do you have the 45 that come out the top of the carb? Even with that I believe a slight twist of the carb off center helped with the routing.
Try to pop the throttle by lifting the cable out the top. Pull the slide out of the carb and check function without spring.
Check the needle for straightness. You need to roll it on a flat surfafe to see it. The slightest bow will cause a drag.
Also, I have pulled the spring to stretched it, to give it a little more force. Not too much.
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Go walk over to your neareast bicycle shop and make friends. Costs less than motorcycle people charge too.
I can't say at the moment, I'm not near my bike. In the morning I'll put a caliper on it. I'd say it has 2/3 the cross section area. More than that though is that it's much more flexible material. The strands are more fine than the original. Cost was around $7.
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