Malossi 112 need advice

[panos08]

I have a malossi 112 with engine cases ported, phbl 24 carb and a vmc tork s exhaust.
Gearing is 22/63 and also have a vape 12v ignition AC.
I tried many idle and main jets.
I can't find an ideal operator.
Current settings are 46 idle 95 main,2nd from the top position for the needle and the mixture screw 1,5 turns out.
Also I have a ramair filter.
The thing is that I don't have power at high revs with jets from 95 to 115.
It seems that everyone looks rich.
I checked the carb and the floats height and it's OK. Any advice?

[jonnysnatchsniffer]

take the filter off and see how it goes

[tzsteve]

Mr.js is usually right.
I take it you have had a look at the plug as a starter.
Have you tried lowering the needle to the top notch?
My filter is a piece of flour sieve gause,

[jbcollier]

I like to dial in the main first after rough setting the idle.

First:
- I assume this is a proper 2T carb with a 2T atomizer? (some suppliers have sold 4T carbs at times)
- You have looked at other people's set-ups and have an atomizer, slide and needle that others have found successful?
- Timing is set correctly?
- Fresh fuel?

So start with setting the idle mix so it idles smoothly with the screw on the rich side of perfect idle (further counter-clockwise).

Find a hill where you can run it wide open in third gear.
Lean:
- when wide open, backing off slightly sees a small improvement (slightly lean)
- when wide open it goes flat (very lean)
Rich:
- it "four-strokes" or stutters wide open

Keep going to a larger size until it starts to 4T wide open and then back down until is just stops 4T-ing and pulls smoothly.

Your main is now a little bit too rich. Leave it there until the kit is fully broken in.

Now, reset your idle mix to best idle on the rich side. Shut it off and count the turns to lightly seat the idle mix screw.
- 1.25 to 2.75, spot-on
- 1T or under, idle jet is too large
- 3T or more, idle is too small

Change the idle jet until you're in the right range.

Now you can dial in the needle. Again raise it until it is too rich and back down until it clears and revs through cleanly.

I now use a wide-band O2 sensor and an A/FR gauge. It takes the guess work out this and makes it all pretty easy. It is also brilliant at find transient, off-throttle lean spots which really kill tuned engines.

[panos08]

Today i tried a 44 idle,mixture screw 1,75 turns out and it feels better.With the filter off dies when idling and doesnt help at WOT so i think i m getting to the right side.The atomizer is a AQ264 and is for a 2 stroke from my knowledge.

[panos08]

Malossi suggests 42 idle 115 main 268 D(?) atomizer and D31 needle. Doesn't suggest any exhaust or any other information about this set up but I think never gonna work with so rich mixture.

[jbcollier]

It dies at idle with the air filter off but idles fine with the filter on?! If so, maybe your rotary pad is shot..

[panos08]

Apr 11, 2022 13:52:21 GMT jbcollier said:

It dies at idle with the air filter off but idles fine with the filter on?! If so, maybe your rotary pad is shot..

With the mixture screw 2,5 turns out it's OK as I assume there isn't a crankshaft problem. Fine tuning is a pain in the ass with the smallies.

[jonnysnatchsniffer]

thats cos yr using wanky dellorto carbs with loads of different atomisers, loads of needles whose charts only italians can make more complicated, especially with atomiser choices, then you got about 4 or 5 slides, mains and pilots
where is the mixture/air screw on the phbl ? if on the front of the carb (the manifold end) then its a mixture screw and 2.5 turns out would mean maybe a size up on the pilot, but id not worry unless over 3 turns out

[tzsteve]

Never had a problem with dellies myself. But a lot of it personal choice i never liked the jap carbs Amal are ok but they can be a bit rough

[jonnysnatchsniffer]

you really need the thing running to set up the idle and mixture screw, i just drilled holes in the side to get to the pwk and mikuni mixture/air with a screwdriver, if you dont fancy holes you can buy a mixture/air screw that you can turn with yr thumb and finger, like this

beedspeed.com/products/bgm-pro-fuel-air-mixture-screw-phbh-phbl?currency=GBP&variant=41299032965306&utm_medium=cpc&utm_source=google&utm_campaign=Google%20Shopping&gclid=CjwKCAjwjZmTBhB4EiwAynRmDwtcO8qWf_CN5aZlBnlzc3CzFbMjbzrwHuGUEiNlTRdxXkOAMG8c4hoC_XAQAvD_BwE

keihin needle charts are easy, say you have a CGL needle the next richer needle is DGL and the next leanest is BGL, fixed atomiser too, the only hassle with the keihin is that when you get one it may come with weird oem multi-taper needles, i just hate the dellorto for ease of setting up well, shit loads too many variables
dellys may not run wot well as the atomiser may be too small, and the needle to big or the other way round which as you know could mean the main jet has little impact at any throttle opening and why some are always too lean even when putting in 115-120 mains in a 24/25mm phbl