Mikuni TM 24 (jetting help)

[Dimitrios_231]

Rapido Classic 225
TM24
Remote filter
JL3 Curly
Lightened flywheel

Had a Sito Ancillotti,in my running in period,
the jetting was :

Main 185 (a little rich)
5N13 2nd clip
pilot 22.5 (rich)
air screw 3/4 to 1 turns out.

The responce was very good, on all the throttle range.

Now for the JL3 curly:

Main 220 (all the others were a little bit lean )
Air screw 1.5 turns out
Others are the same.

Now with the 220 main jet,the lammy goes great from 1/2 to full throttle.

It starts easily all the time.
Cold with choke,warm without.
When I start it warm and open the choke, the engine cuts out.

Between closed and 1/8 the responce is good.

My problem is between 1/8 to 1/2.
When I open the throttle,it doesn't pick up speed immediately and feels boggy.

2 questions

Do I have to lower the pilot jet?
Don't have the 20 (waiting),but I have a spare 17.5
Do I risk to try the 17.5?

Do I need to move the clip in the needle?
If so,do I need to make it richer or leaner?

Cheers.

[bazman]

I'd be inclined to richen it first (by the needle if no bigger pilot jet available) as sometimes the "boggy" effect can infact be lean mixture. Nothing to lose richening it, but lots to lose leaning it off!!! Worth a try?

[oldbiker]

steps in tuning a carb:

this is how I do it (from amal and dellauto data)

1 > get it to tick over. as smooth as possible without choke when the engine has warmed up

2 > remove the main jet, start the bike and adjust the needle/needle jet,,,

if you lower the clip on the needle the engine runs richer..

the engine should run ok and be rideable up to about 1/4 throttle. 1/3 throttle the engine should feel rich. at about 1/2 throttle the engine MUST stall due to being to rich, (you now have the correct pilot jet, needle/needle jet.)

3 > now start trying the main jet (start a little rich and work down)

4 > if you want to be fussy you can mess about with slide cut away, but really you should not need to/
(spitting back from the carb at low rpm is usually due to too small a cut away)

im sure that others will offer hints and tips, but you should really test the carb with no main jet as this is the only way to know if the needle and jet can flow enough juice

[Dimitrios_231]

I have a 25 pilot,
but with the current one (22.5) the spark plug looks black and oily at low revs.

I use B9ES
and 4% semi synthetic oil,
cause I need 100 more miles to complete the 1000 miles of the running in period.

[Dimitrios_231]

steps in tuning a carb:

this is how I do it (from amal and dellauto data)

1 > get it to tick over. as smooth as possible without choke when the engine has warmed up

2 > remove the main jet, start the bike and adjust the needle/needle jet,,,

if you lower the clip on the needle the engine runs richer..

the engine should run ok and be rideable up to about 1/4 throttle. 1/3 throttle the engine should feel rich. at about 1/2 throttle the engine MUST stall due to being to rich, (you now have the correct pilot jet, needle/needle jet.)

3 > now start trying the main jet (start a little rich and work down)

4 > if you want to be fussy you can mess about with slide cut away, but really you should not need to/
(spitting back from the carb at low rpm is usually due to too small a cut away)

im sure that others will offer hints and tips, but you should really test the carb with no main jet as this is the only way to know if the needle and jet can flow enough juice

Thanks steve,
I'm a little bit lazy to do this.

At the momment I'm looking for ideas.

I'm thinking to lower the pilot (17.5)
and lower (make it richer) the clip.

[Dimitrios_231]

I'd be inclined to richen it first (by the needle if no bigger pilot jet available) as sometimes the "boggy" effect can infact be lean mixture. Nothing to lose richening it, but lots to lose leaning it off!!! Worth a try?

Will do it tomorrow,
and see what will happen.

Cheers.