M8 Top-end Rebuild

[Joker09]

Hi all, I got an 07 M8 with 2000 miles on it so at the end of this year i plan on doin a top-end on her. Was just curious, is there any brand of kit that sticks out over the rest or are they all about the same? The other thing i was wondering, would it be worth sending the jugs off to be ported? I am already running the SLP pipe kit, was just wondering if the porting would bring out more and still keep reliability. If not, would I be just as happy buyin a BD box to clean up the fuel system? Thanks guys.

 

[JasonAK]

I have around 3500 miles on mine and have been thinking the same thing. I have also been slowly taking fuel out of the bottom on mine and it is running much better. I think I going to buy a head and have the jugs ported this summer. More than likely I will use Arctic Cat pistions and rings though.

Jason

 

[Joker09]

That was the other thing i was thinkin about. Im plannin on goin with SLP porting, but whose aftermarket head should i go with? Anyone got any opions on em?

 

[ItDoAble]

Mine's RKT head, ported, SLP pipe .. added in order over the years (07 M8). Pipe made a huge difference on the top end, pulls like a madman. Still not as crisp on the low-mid (4500-5500) as with stock pipe, but I'm still messing with the box. Bud has only the pipe on his 09 and mine pulls much harder at ~7-8K RPM.

 

[JasonAK]

Mine's RKT head, ported, SLP pipe .. added in order over the years (07 M8). Pipe made a huge difference on the top end, pulls like a madman. Still not as crisp on the low-mid as with stock pipe, but I'm still messing with the box. Bud has only the pipe on his 09 and mine pulls much harder at ~7-8K RPM.

What kind of power gains did you see with just the head and porting? Enough to justify the cost? I have the SLP pipe and I agree the top end is great.

Jason

 

[ItDoAble]

What kind of power gains did you see with just the head and porting? Enough to justify the cost? I have the SLP pipe and I agree the top end is great.

Jason

Saw decent gains with the Head & Port, maybe 5hp per mod (seat of the pants). There wasn't an effective altitude (10K) M8 pipe until last year ..

Starting from scratch on an 07 again, IMO I would go 1) pipe, 2) torsion secondary kit, 3) Powerclaw, 4) weight reduction, 5) suspension, 6) port (need fuel box), 7) head.

Others might have different opinions ...

 

[Joker09]

So i tried searchin around on here but couldnt find any info on who has the best top end kit. So, would i be better off goin with all cat stock parts(pistons, gaskets, bearings, etc) or would someone like Wiseco be a good choice? Just want some real reliable parts.

 

[mtn_extreme]

Go with cat parts, most reliable out there. What we run on our turbo's.

 

[BigAir]

Everything I have read says the stock Cat pistons are the best. If you go Wiseco make sure your piston to cylinder clearance is right and warm it up good before riding it. Forged pistons expand a lot more than cast pistons. More likely to cold seize.

If you decide to go with stock PM freeagent on here. She has awesome prices on top end kits.