how big can a 61x cyl.go??

[sj1million]

Hey dudes, Im new here and getting into the ski thing more and more!

I have a 2000 SJ with type 8 dry pipe and riva head (not sure what domes are in it) and an MSD enhancer and a few hulland driveline mods. It is stock bore and worn out pretty bad, it only has 135 lbs compression but still runs pretty strong.
Im wondering what the largest bore I can go with these cylinders and what dome I should go with to run pump gas.
I talked to riva and they said I could only go to 82mm bore with these cyl. But I have heard that 84mm is possible. If so what would the recomended piston/ dome combo be? and still run pump gas...

ohh and the little turny knob on the MSD enhancer, what does it do?

 

[Matt_E]

Some folks will tell you 84mm is past safe, and some won't. There's stories backing each side up.

Personally, I wouldn't bore up past what's necessary for a rebuild. Go to 81.25 or 81.5, and no higher.
The added power from the additional displacement is negligible. Get the cylinder ported - much much much more bang for your buck.

Oh, and get rid of that Type 8. Supposedly it's the biggest turd ever made by Factory Pipe.

 

[sj1million]

what would be the best all around pipe? uuhhh I guess more freestyle than racing.

 

[yamaslut]

Some folks will tell you 84mm is past safe, and some won't. There's stories backing each side up.

Personally, I wouldn't bore up past what's necessary for a rebuild. Go to 81.25 or 81.5, and no higher.
The added power from the additional displacement is negligible. Get the cylinder ported - much much much more bang for your buck.

Oh, and get rid of that Type 8. Supposedly it's the biggest turd ever made by Factory Pipe.

pretty much sums it up.... please do not bore it to 84mm unless it has to be due to damage. I've seen cylinders w/ that cut and it's scary looking

 

[yamaslut]

what would be the best all around pipe? uuhhh I guess more freestyle than racing.

Factory B pipe w/ mod chamber...

it's the industry standard...

you can also run a TNT chamber on that setup too...

 

[Matt_E]

what would be the best all around pipe? uuhhh I guess more freestyle than racing.

B-Mod or Limited for SJ, or Blaster Mod (all FPP) or Speedwerx dry.

 

[douglee25]

The Riva red pipe is also a good alternative since B-pipes have become scarce.

Doug

 

[waxhead]

i am with the b-pipe
i go to 83mm i like thta bore size
i have bene to 84.25
but its startng to get thin
groupk will happily go to 84.5mm

 

[Matt_E]

If you go to 83mm, you will have to carefully check the squish in whatever 701 head you are using. If you have to bore up from there, you will need to use a 760 head, or get the other head recut.

 

[sj1million]

Would I be able to cut the domes I have now for 84mm?
What should the squish be?
and what pistons should I go with? siezeco?
and what about flat top vs. domed pistons?
Im probably going to go with 82mm so I dont have to get or recut domes.

 

[Matt_E]

Here's my advice: Go only one size over. If you are at stock bore, that will be 81.25mm. Go to 82 if you want, but there is no point to that.
You will not have to bother with cutting domes.
The squish should be okay, but I would check it anyways. (larger than 0.040 I believe...don't take my word for it!)
If you want flat top pistons, you will need different (Custom?) domes.

 

[sj1million]

alright, Im ordering pistons tomorow. I guess Im going with siezeco..

 

[Matt_E]

Why Wiseco? If I were you, I'd stick with OEM, Pro-X, or Sudco.

 

[douglee25]

Why Wiseco? If I were you, I'd stick with OEM, Pro-X, or Sudco.

Or Vertex:smile:

 

[Matt_E]

Where do you get the Vertex?

 

[waxhead]

if you want some wiseco then let me know
i have some 82 mm ones already
and they are the old style that dont collapse the sleeve

 

[sj1million]

old style? collapse the sleeve? what.....?

 

[waxhead]

opps my bad i mean skirt the new wiscos collapse the skirt
i got warranty on a whole heap of them from wiseco

 

[yamaslut]

get Pro-X pistons... end of story

 

[sjetrider]

riva dry pipe

The Riva red pipe is also a good alternative since B-pipes have become scarce.

Doug

I have a riva dry pipe for $300.00 if ur interested, but as for a type 8 (run forest run)
and as for the 84mm bore, seen it done many time w/o fail, but no need to go more than you have to, cuz replacing sleeves next time costs mucho denairo, money best spent on porting assuming they are not already ported.