I know this is considered crap but I am to old to kick the thing with Amals when they crap out in traffic this thing is a 1 kicker and since I went from the round side to the flat slide it even has more power than the twin 32s runs great but has anybody ever tried to pilot jet a flatside on a 850? I am down to a 20 pilot and still have to have the air screw out further than I would like. I am abut to the point of running it out the 4 turns that run good and putting a glob of silicon on it so it does not vibrate out. Any help? Thanks Tony
34mm Mikuni flatside
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Yeah, and it is a brand new carb and runs perfect off idle and the plugs look good on a chop I am running the needle in the leanest slot I am beginning to believe that since these carbs are mostly used on 2 stroke racers the idle passage must be huge I have a 17.5 pilot I am going to try next week and then the blob is going to get the mixture screw. Someone had said air cleaner because the 34 kit (round slide) cvomes with a 1 inch thick K&N so I blanked off 1 of the carb inlets on a twin carb K&N and turned it down so I know I am not choking it, that is a thought maybe I will pull out the cold start and make sure it is seating.
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These are good threads on jetting TM34's. The pilots seem to run more than 20, so if you're needing a lot of turns on the air mixture screw with a #20 then you might need to check the float level. Probably always a good idea, new or old anyway.
post103105.html#p102993
These are good threads on jetting TM34's. The pilots seem to run more than 20, so if you're needing a lot of turns on the air mixture screw with a #20 then you might need to check the float level. Probably always a good idea, new or old anyway.
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Hey Stang,
Don't be frightened to try that 17.5, some carbs just like to be different.
It does sound very lean though.
Just wondering if the Air/Mixture passage is clean and unobstructed.
It may have a moulding defect.
AC.
Don't be frightened to try that 17.5, some carbs just like to be different.
It does sound very lean though.
Just wondering if the Air/Mixture passage is clean and unobstructed.
It may have a moulding defect.
AC.
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stang484 said:
Firstly see if it has an air corrector jet (tiny jet screwed into one of the bellmouth intake drillings), if so try the next size down. If you dont have an air corrector simply fit a smaller pilot jet, and after you have pilot adjustment right, then check the needle and main jet sizes are correct for your bike.
Float level makes very little difference to how well a bike runs, unless its a really long way out, or the carb is flooding for some reason.
In general flat slide carbs will work much better than round slide types, as the design of the slide means less turbulence in the area of the needle jet, which results in a stronger intake signal to the jets themselves which means more precise carburetion and greatly improved running.
Carbonfibre said:
You're right, I forgot that they often ship them without any air jet at all. #2 seems to be the one most cited.
If he is using smaller and smaller pilot jets and opening the air screw to the limit isn't he trying to overcome an over rich condition and adding the air jet might put him further from where he wants to be? I chased a similar problem and found that even the factory float level was too high because the floats themselves were old and gas sodden to a certain degree. I lowered the floats, went back to standard pilot and got the kind of reaction to air mixture screw adjustments you'd expect, and it transformed the tip-in off idle response in the bargain. It was probably off by quite a lot.
Don't have air correction jet and found I don't have a 17.5 as the sealed bag was miss marked so now I am back to the 20 it runs well with the 20 and the air jet out 4 turns I checked float level mixture inrichment valve blew out all the passages I could find and everything looks great. So now I am running the ait screw out of the round slide (has more threads and is longer on the screw side same lenght and shape of jet) turn it out the 4 turns put a blob of clear silicon on the screw and tommorow look for a true 17.5 or a 15. BTW it runs great will idle forever smooth as silk on opening a little at a time and pulls like a tractor on NOS. So if I can't find a smaller pilot I will just watch the Blob (anybody else old enough to remember that movie firdt time with Steve McQueen) Tony
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If you are in the US try Sudco for correct size jet, if in the UK Allens Performance will be able to help...............
Well, I got it worked out the builder of the carb only ran his tap about 2 full turns into the pilot jet hole, so the jet was basicly doing nothing as the fuel was just running above it trouble is by the time I worked it out the 2 turns of thread were messed up and I don't want to have to tap a new carburetor so now I am waiting for the seller to tell me that I screwed it up and they are not going to do anything(my guess) I will not mention their name till they do it is a $125 part so we will see if my future business and everybody I can tell is worth it. We will see.
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when you get it corrcted -
here is the settings for my TM34 - runs/starts perfect
i do have my needle clip a notch down from middle so that may be a slight difference that may influence the pilot in my settings - but having a 20 does seem quite small - that being said you could try a 17.5 - but hey if it runs good and the idle is smooth w/ a 20 i wouldn't worry to much
tm4 34mm single - 850 73 8.5:1 CR stock cam
Main Jet 240
Pilot Jet 30
Needle Jet type 389 size P-0
Needle 6DH3 ( 4th notch down)
Air Jet #2
slide 4
here is the settings for my TM34 - runs/starts perfect
i do have my needle clip a notch down from middle so that may be a slight difference that may influence the pilot in my settings - but having a 20 does seem quite small - that being said you could try a 17.5 - but hey if it runs good and the idle is smooth w/ a 20 i wouldn't worry to much
tm4 34mm single - 850 73 8.5:1 CR stock cam
Main Jet 240
Pilot Jet 30
Needle Jet type 389 size P-0
Needle 6DH3 ( 4th notch down)
Air Jet #2
slide 4
FWIW,
My TM34 setup for a 72 Combat, 2S cam:
Main Jet: 240
Pilot Jet: #35
Needle Jet: Type 389, Size P-O
Neelde: 6DH3
Air Jet: #2
Slide: #4
Mine runs a bit rich, but switching to BP6ES NGK's in place of the 7's solved the blackened tendency with the plugs....8500 miles of pure Joy!!!
My TM34 setup for a 72 Combat, 2S cam:
Main Jet: 240
Pilot Jet: #35
Needle Jet: Type 389, Size P-O
Neelde: 6DH3
Air Jet: #2
Slide: #4
Mine runs a bit rich, but switching to BP6ES NGK's in place of the 7's solved the blackened tendency with the plugs....8500 miles of pure Joy!!!
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stang484 said:
If you were having problems with an Amal then I would believe that threads may well not have been tapped properly, but never ever heard of Amal type "quality" on Mikuni carbs, so I would imagine you are going to need to try very hard to convince whoever sold you the carb that it was defective.
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