4 mill spacer plate ?

[Jaystre]

I want to know if a spacer plate is requiered using a 4 mill crank ? I heard of spacer plates between the cases and cylinder to keep good port timing or somethimg like that . When i took my engine appart there was a spacer between the head and cylinders . Do u have to adjust port timing when using a 4 mill? Any info would be apreciated. thx.

[alf44]

Havin g your domes custom cut is the better way to go. You will need to have your port timing adjusted as well. Take your bottem end, cylinders and head to your builder and the'll hook it up for you. Its the safest way to go. If your Cylinders are already ported for a 4mill I think Jeff at FAST has some off the shelf 4mill domes available now. Give him a shout. I have some for a 68mm bore in a 9 deg. and a 13 deg. Short and long rod.

[Larry's Shee]

That's too funny !!! Exact same thing happened to me. Had to pull my son's 'shee apart after he drowned it in a mud hole. His has a 2mm solid copper head gasket. X-2 on the porting, piston will be 2mm below transfers at BDC , plus transfers will open late ,kinda like the difference between an enduro and a mx bike. upper would not raise 2mm because it has to do with degree of crank rotation. Do to lack of $$ , it will get porting and either mod stock head or cool head next time.

[Jaystre]

ok i see . Is this something that has to be done ? because was set up like that when i bought it ...then again the previous owner probably didnt no shit . will it harm the engine?

[spurdy]

ok i see . Is this something that has to be done ? because was set up like that when i bought it ...then again the previous owner probably didnt no shit . will it harm the engine?

 

Shouldn't hurt it, it just may run like shit. The changing of the port timings is like changing the cam in a 4 stroke. Best to let a builder look at them or take some measurements of the porting and check on here with guys that know more about porting.

 

SP

[Larry's Shee]

Only draw back to running it as is is that you won't be getting maximum potential from the added displacement. My son's runs good enough ,it doesn't even have pipes on it. You didn't say why you tore it down in the first place. Also ,what other mods do you have?

[Jaystre]

Well i tore it down beacause i broke a piston skirt .Too much clearance between piston and cylinder is my guess . And when i got it apart i noticed the crank was separating ...so ended up tearing it all apart . Also notice there was one teeth missing on the clutch basket and that big chunk was no were to be found. Just seems to be one thing after another . Anyways mods are fmf sst with powercore 2 ,k&n pods with outerwears , tors removed, coolhead 21 cc domes ,timing plate +4 .

[Larry's Shee]

So I presume that your thinking of 4mil for crank replacement as opposed to fixing present crank?

[Jaystre]

So I presume that your thinking of 4mil for crank replacement as opposed to fixing present crank?

 

Yes . well there was a 4 mil originally in the bike when i bought it . And before i discovered the crank was separating i ordered myself a set of 795 series pistons as well got my cylinders bored to match the pistons . I was told the seperating crank was not repairable . So brand new one on its way! I guess ill have to look into porting soon enough .

[AKheathen]

lol, the head spacer doesn't do anything to port timings. do the domes for reliability mostly. the head spacer is prone to leaks. the porting will give you a lot more power

[Jaystre]

Do you have to re-bore after a port job ?

[Larry's Shee]

No , whoever ports it will champher them at same time.

[AKheathen]

Do you have to re-bore after a port job ?

no, your pistons will decide if you need a bore, and you need a hone for new rings, but porting does not require re-bore, or hone.

[Jaystre]

Thx for all the advice guys!