mugello 186 problems

[Scooterlam]

For what its worth and this is from memory,
Avanti Pistons abcd increments are 0.01mm. if this is industry standard I don't Know.

[Donnie]

Ride scoot as it is now for about 200 miles to let it colour up, Then remove barrel and check piston for blow by,
if it is clean then the piston rock was probably caused by the piston hitting the head due to the carbon build up which was in excess of 2 mm.
Phil

Don't forget to retorque the head at about 100 miles mate.

[TS1-200]

Did you not do the easiest thing first and re pack the end can with fresh wadding, I expect the perforated tube would have blocked up holes and the wadding would have got oil soaked and gone hard,

[phil99]

hi

thanks donnie for the reminder to retorque the head down.

thanks TS1-200 but i dont have an end can.

latest update from the supplier is they checked there stock and they had a bad batch of pistons.

have now received a new A sized piston.

rode scoot 100 miles took the top end off and there was no blow by on the piston.

clearances received from cam lam are bore clearance 0.07 mm to 0.013 mm and ring gap 0.28 mm to 0.40 mm.

checked the new piston and rings and the clearances are within cam lams specification.

all fitted, ready for running in.

thanks for all the advice.

regards phil.

[Warkton Tornado No.1]

Hi Phil.

bore clearance 0.07 mm to 0.013 mm

Do you really mean:

0.07 to 0.13 mm

which is 0.0028" to 0.0051"

rather than 0.0028" to 0.00051"?

Just over half a thousandth of an inch is surely a typo.

Sorry to appear pedantic.

[phil99]

Hi Phil.

bore clearance 0.07 mm to 0.013 mm

Do you really mean:

0.07 to 0.13 mm

which is 0.0028" to 0.0051"

rather than 0.0028" to 0.00051"?

Just over half a thousandth of an inch is surely a typo.

Sorry to appear pedantic.

Hi I thought it was an error but forgot to take it off the last post.

this is the email i receved from cam lam after I sent them some pics of the piston.

Looks like carbon build up excessively rich or he isnt running it hard enough to burn oil and excess fuel, is he complaining it is running poor? i would check bore clearance and rings gap at that mileage bore clearance .07mm to .013 mm mx rings .28 mm to .40 mm mx if ok de coke remove carbon and rebuild with new gaskets poss new rings depending on clearance, i would rather see this than a holed piston at least its been running safe .