somethings that we all can do is polish the sleeve and the crank...

some people say dont polish it coz the fuel/oil wont stick... or something...

i see jp engines dont have polished crank or sleeve....

what are your opionons on polishing the sleeve and crank?

I wouldn't bother touching these components other than regular cleaning if you arent familiar with them. If you polish the wrong area you could cause wear (crank pin, inside of sleeve, etc..).

NEVER touch the inside of the sleeve where the piston goes...EVER!! Do this and you might as well throw away your engine..

John

Never touch the sleeve.

I wouldn't go messing with port polishing either. The fuel/air needs to mix around together and if your ports are smooth surfaced then there is less chance of the fuel and air mixing together if you had rougher ports.

So basically, your engine would perform better without the port polish because of the fuel/air mixing together.

Sean

Question for modders : Sleeve Porting but not crankshaft

What mod that increase maximum rpm ? shall I mod ( porting ) the front ? The side ?

I don't want to mod all ports for fuel economy reason.

Increase exhaust timing by .3 mm (aprx 6 degrees) and don't polish anything in the motor.
Edward

side porting 4 more power..

When you said increase timing by .3mm : Should I dremel upper or lower lip of exhaust port ? I guess is lower side right ?

Upper line of exhaust window. Don't use dremel, use needle file, daimond kind.

Thanks..... TopGun 777

It's LL5 engine I recently bought from Daniz24,

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So what is the advantages of modding besides its disadvantages? Does it acts the life of the engine?
And can you classify the type of moddings, how is it done simply and why is it done for?

When measuring the induction duration, I put the piston at BDC. After that I rotate the crank CCW until it opens. Degs measured may be for example 35*. Then I rotate it CW until it opens from the other side( it is actually the closing side). Degs measured may be 232*.

232*-35*=197* duration. Is a proper method of measuring the induction duration?

I can't get ATDC measurements because the piston gets stuck.

Any one have an answer to the above question

.

Yep if piston still tight in the sleeve this is right method to mesure. In your case induction is open @ 35 ABDC and close @ 52 ATDC with total duration of 197 deg of opening.
As a sugestion-opening is OK, but closing is too early (for on road engine) at list by 5 degrees.
Edward