Anyone get tight squish numbers using Carillo H-beams in a SV650? I'm using oem gaskets and the cylinders have not been decked. Using rosin filled solder to measure squish and numbers are tight! Pistons are from a busa.
They are. I'm using busa pistons in Gladius (nikasil) cylinders. The cylinders haven't been decked and with oem base gaskets I'm right on the edge of no mans land.
one guys no mans land is another's comfort zone... the key is to know the difference. squish varies a lot depending on type of rod your using let alone piston designs.. just saying. If your not comfortable, change it by getting custom base gaskets or decking pistons a few thd's. You wont notice .002" in hp but you will upon contact..
Already have base gaskets enroute to get it where I feel comfy. The SV flexy crank needs a bit of room to dance...
The rods aren't longer. The Busa piston's wrist pin location is lower. This is one reason why the compression is higher with those. Why are you using Busa pistons anyhow? There are better stock bore pistons for racing. Are you using the Busa rings too due to the nikasil cylinders?
Negative. Distance from wrist pin to top of pistons are the same. Why busa pistons? They retail for 100 bucks each brand new, they weigh about 306 grams with all the goodies attached, and they're strong enough to survive in a street busa with 220hp at 5psi of boost. A set of custom pistons that weigh about the same as stock SV pistons (317 grams) run about $520 I might be limited on compression due to PTV issues with the big cams I'm using but they're other ways to deal with that. Right now with the squish I'm using and .030 off the heads I calculated 12.6:1 comp ratio. I'd like to get to 13:1 Yes, I'm using busa rings to comply with the nikasil bore on the Gladius jugs.
So if your heads have .030 off of them, what about .040? The reason I ask, I was given a set of heads that have what we think is .040 off of them and I'm wondering if I should keep them or just pitch them.
If he's using Gladius cylinders he will have to use the Busa rings since both (busa and Gladius) are nickasil coated. At least that's my understanding.
I'm sorry did you say 30 thou off heads???? Wow. Also Busa pistons are great piston I just don't use as in prod builds we can't and in SBK most guys want custom.
Oh I know you can take 30 off. Done a ton of SV. Just never had to take that much off. No worries. Good luck
Yes they're junk. Send them to me..... You can use them but you're gonna have to do some measuring. Most likely, cam timing will have to be changed to get correct PTV.
Pistons are dished so I'm chopping to get compression. I guess it's left over from the good old days of WERA LW Superstock suzuki cup money, it was not uncommon for racers to chop 050 and even 060 off the heads, degree the cams, and let em rip.
The busa pistons are a bit bigger even though they both say 81mm. The busa slugs can fit tighter (Nikasil) so the slightly larger busa rings close up the ring end gap. The SV rings will work but end gap is kind of out there. Plus there's an arguement that busa rings are suited for nikasil and sv rings are not beacuse they are made for iron bores. Not sure about that though..
True. And if you use Busa rings the end gap may be too small, which is worse than too big, but fixable. And, per your comment in an earlier post, 0.060" off an SV head will lose power over a properly set up engine with half that. Taking that much off the heads is a bit hackish.
Sent you a request on the facetubes... Seriously though, if you end up needing them hit me up. It's going to be a while before I tear into my 2nd gen motor so if you need them we can work something out. They are 1st gen heads.
I think you need to check your measurements. And as to custom pistons...$360 for the set...lighter than stock SV pistons (but heavier than 2mm over pistons). Want me to show you a picture? You want 13:1 comp...that's pretty low? I usually run 14.2ish. Also you said you took .030 off...what did you end up with on your head volume? That's the real number to care about.