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Mikuni TM 24 bogging down with breathe sweet filter
Posted: Sun Jun 26, 2011 2:52 pm
by DaveTomo
running classic rapido 200 with a Mikuni TM 24 settings are Main=180 ,Pilot=15 , 5N13 needle clip at top , air screw 1/4 turn out,still trying various combo's of starter/main jet but thats whats on it today

12v AC timing set at 19 BTDC and a 42mm AF Clubman.Put a breathe sweet filter on this afternoon sounded like it was gasping for air,opening the throttle is was bogging down till eventually it cut out,took the filter off,quiet a bit of fuel in the hose.Kicked up first time (with out the filter) and seemed to go OK

admittedly its still a bit "boggy" when you open it up but then picks up fine past 1/4 throttle.Any ideas which way to go jet wise,up or down?or take it down on the needle? whilst its being set up have got the flick choke on to take it out of the equation
Cheers Dave
Re: Mikuni TM 24 bogging down with breathe sweet filter
Posted: Sun Jun 26, 2011 7:49 pm
by red ghost
If the clip is on the top of your needle, than maybe you should look into a leaner needle jet..or try a different needle, a 4DH7 is a popular choice.
Also, check (I don't know how) when you fit the filter, make sure that the rubber dosen't deform and cover the little air holes on the front(mouth) of your carb.
Re: Mikuni TM 24 bogging down with breathe sweet filter
Posted: Sun Jun 26, 2011 8:12 pm
by DaveTomo
red ghost wrote:If the clip is on the top of your needle, than maybe you should look into a leaner needle jet..or try a different needle, a 4DH7 is a popular choice.
Also, check (I don't know how) when you fit the filter, make sure that the rubber dosen't deform and cover the little air holes on the front(mouth) of your carb.
Cheers Red,I've had to stop playing with the carb at the moment (don't want to upset the neighbours) but day off tomorrow so will give it another go.Thats a good piece of advice about the rubber deforming,hadn't thought of that,must admit a standard 22 mm air hose does seem to fit better over it so might do some experimenting :freak: and maybe make a Frankenstein filter out of a standard air hose and the breathe sweet filter.I've also decided to go back to basics and start again with the needle,pilot and main jet using this
http://www.smellofdeath.com/lloydy/jetting.htm .Again thank you for your advice.Dave
Re: Mikuni TM 24 bogging down with breathe sweet filter
Posted: Sun Jun 26, 2011 11:03 pm
by corrado
Using a TM24 with breath sweet on my Mugello 225, I think I'm using 17.5 pilot and 190 main jet, 5N13 needle on 2nd clip. 4 strokes between 1/4 and 1/4 throttle but fine above that. I raised the needle clip to the top but it made no difference to the 4 stroking and the plug looked a bit too clean for my liking so I've dropped the clip back to pos 2. I think the problem lies in the atomiser. Standard is Q0, I'm using a P8 but I want to try some lower ones, P6 and P4 to see what effect that has.
Re: Mikuni TM 24 bogging down with breathe sweet filter
Posted: Sun Jun 26, 2011 11:28 pm
by sideout
I have a TM24 running through the airbox on a Muggy 186. When I moved the clip to the top on a 5N14 needle it was still a bit rich in mid range, so like Red Ghost advised previously, I got a 4DH7 from Mr Corrado and it sorted it out a treat! Very impressed so far....

Re: Mikuni TM 24 bogging down with breathe sweet filter
Posted: Mon Jun 27, 2011 2:48 pm
by corrado
I keep resisting the urge to use the 4DH7 needle because it's spot on over half revs. That and the fact that doing anything needle related on a TM24 is a real pain in the rear.
Re: Mikuni TM 24 bogging down with breathe sweet filter
Posted: Mon Jun 27, 2011 3:58 pm
by DaveTomo
well some progress today now on 17.5 pilot jet ,180 main, 4dh7 on the second clip from the top,air screw 2 turn outs + the breathe sweet filter,now revs OK all through the range,no bogging down,running a bit rich but I'm Ok with that for now will take it up a clip later. done a few plug chops and like I say a bit on the dark side (black) but very happy with the revs.
edit: now on top clip,plug much better
Re: Mikuni TM 24 bogging down with breathe sweet filter
Posted: Mon Jun 27, 2011 9:43 pm
by sideout
corrado wrote:I keep resisting the urge to use the 4DH7 needle because it's spot on over half revs. That and the fact that doing anything needle related on a TM24 is a real pain in the rear.
I found the rear pain was reduced after fitting the 90 degree Dellorto elbow and cable adjuster Martin. I just slacken the cable off and it makes the job tolerable (not something I'd want to do every day though
Dave: That's exactly what I'm running on the Mugello 186 through the airbox, but mine's on the second clip position.
Re: Mikuni TM 24 bogging down with breathe sweet filter
Posted: Tue Jun 28, 2011 9:54 am
by red ghost
sideout wrote:corrado wrote:I keep resisting the urge to use the 4DH7 needle because it's spot on over half revs. That and the fact that doing anything needle related on a TM24 is a real pain in the rear.
I found the rear pain was reduced after fitting the 90 degree Dellorto elbow and cable adjuster Martin. I just slacken the cable off and it makes the job tolerable (not something I'd want to do every day though
Dave: That's exactly what I'm running on the Mugello 186 through the airbox, but mine's on the second clip position.
I don't understand why it's painfull, I can do a needle adjustment in under a 3 minutes..that's with panels and air filter

Re: Mikuni TM 24 bogging down with breathe sweet filter
Posted: Tue Jun 28, 2011 1:12 pm
by corrado
red ghost wrote:
I don't understand why it's painfull, I can do a needle adjustment in under a 3 minutes..that's with panels and air filter

I have to remove the headset top to slacken the throttle cable. I'll spend 3 minutes looking for the right screwdriver to release the small screws that hold the headlight surround on, then another 3 minutes looking for the tiny phillips screwdriver to release the needle. :shocking: