hi all, i have a mega mf.12 ceramic ( hand tuned, made by nova rossi ) i run it about 3.5 liters now.

yesterday i had a club meeting and started the engine up for the first qaulification, in the begin the motor run pretty rich, so whe leaned the engine and it whas getting much better, temperature whas also good, after that i had the final.

after starting the motor for the warmup, the engine whas running verry rich again, and temperature whas pretty high, so we puth it richer on high needle and leaner in under needle. buth it didn't help, does anyone know what to do?

in low rpm the motor whas running so rich that it didn't even drive, so we leaned it and it went better, when it commes at higher rpm the engine whas getting faster like it used to be. i changed the plug already buth didn't help.

can anyone help me? sorry for my real bad english

Try richening the high speed and leaning the low speed some more.

a top racer who used to run the max told me the bearings sometimes go on these engines. check to see if there is up and down play on the crank.

also check the seals on your backplate, and carby. put a small bead of silicone gasket around the o rings to close it up.

also check your needle o rings. if it has been doing this fromt he word go, it may be the seals. maybe you didn;t notice this in break in because it was richer, and still being bedded in perhaps?

mine did the same thing. I chased the engine for 2 weeks...even when I got it to idle, it went to 250+deg. I found a trash can and dropped it in. Problem fixed

Trash can??!! Are you serious?

Was it the original MF or the MF MasMo II?

We have most guys at our track running Mega engines and lately or over the last 6 months i have seen and experienced the same with my DSII.
There seems to be carb issue with guys having to chage orings regularly as they get damaged fairly quickly.
I have run just on 6 liters on my DSII but have changed carb orings on 4 occassions know and have changed the carb now too.

So check it might be your problem too.

I use the MasMo motor myself and found it to be by far the best engine I have tried. If your motor tune is going from severely rich to tuned or lean when warm you need to look for an air leak. It sounds as though once everything warms up and expands an air leak is developing. I had a similar problem with my Orion motor, I would suggest you check your backplate and, and all collaborator seals. Put the engine back to factory settings to get you in the ballpark and go from there.

Mark

If tune is changing look at hsn and lsn needles are not moving when the orings get bad.Learnt this lesson at the recent nats when a buddies car kept getting hot after it tempted ok in the warm up.
The vibration saused teh needle to turn in leaning teh engine out.

Hi, could anyone advise where to i get the Mega zx12 dsII manifold casket and would wonder what other brands fits. I've tried several and had found that the manfold casket doesn't sit fit the engine.

What manifold are you using with the DS II? a Mega/Picco based or a Nova Rossi based manifold? there is an original gasket for the Picco engine on a Picco based manifold and a Gasket to be used on a Picco engine on a Nova Rossi based manifold.

Well, It's a combo set i bought from the LHS that come with the mega pipe and mega manifold.

The only gasket you can use is MEG202148 or 202149 for the MEGAZX 12 DSII only because it is a PICCO base motor.

Thanks

Can you guys post the original carb settings for the MEGA MF12?

Thanks!

How much is a piston,liner and conrod set for this engine?