Exciter SX head gaskets

Throttle Junkie35

Throttle Junkie35

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Im sure this question has been asked before and has been done to death, but I'll ask anyway.LOL. Has anyone ever measured the compressed thickness of the standard OEM exciter head gaskets and the sx head gaskets? I know the SX is thinner, but by how much? I have used both sx and non sx gaskets along with cometic and winderosa. Im wondering what difference is between the sx, non sx, and aftermarket gaskets. If I know how much thicker the aftermarket gaskets are, im thinking of machining my heads to get sx spec (maybe a little better) and run aftermarket gaskets because at $40 a piece it gets expensive changing set ups.
Another question I have is, what is the minimum acceptable squish allowable on these 570's?
Its seems as tho there is a wealth of knowlege on this site so I cant resist to pick the brains of the "brains" on here. Awesome site!!
 
Thanks for the reply and the offer, but I actually already have two sets of psi twins and the matching psi ported cylinders. Psi twins are nice pipes for sure, but the RPC single I am currently running works better for my riding style. The Rpc single has alot more low end grunt which works very well for the trails in my area. Lots of tight twisties. There are not many lakes around here to fully utilize the potential of the psi twins where they really shine. Thanx again tho.
 
I don't know how thick SX gasket is, I use to take apart stock ones and make them as thin as you want.

It's cut .030 from the other post. What is you squish now?

I'd get this motor to live longer before doing any more mods
 
Ya Doc, your probably right.LOL. Well my question was being asked just for some general knowlege as I have two other motors I will be building over the summer.
I have motor from psi that I will put back together as it is. The cylinders are stamped PSI4500. Does that mean anything??
I also have a bunch of RPC parts that I have collected over the last few years to build a Phase III motor. The only thing I dont have is the RPC twin pipes.
As far as the squish on the grenade Im currently working on, It should be .030 less than stock, because I had the head cut.(non sx head) Im waiting on new pistons for that one. They should be in today tho.
Thanx for your input doc.
 
JUNKIE YOUR RIGHT ABOUT PIPES. I HAVE PSI TWINS ON MY EXCITER SX, BUT I WILL TELL YA MY BENDER RACING SX SINGLE PIPE HIT LIKE A TON OF BRICKS DOWN LOW. 3:16 (yammie tony)
 
tony. there was a counter balance weight that went on the mag side to better balance the 570 with twin pipes.
 
YAMMIEGOD3:16 said:
JUNKIE YOUR RIGHT ABOUT PIPES. I HAVE PSI TWINS ON MY EXCITER SX, BUT I WILL TELL YA MY BENDER RACING SX SINGLE PIPE HIT LIKE A TON OF BRICKS DOWN LOW. 3:16 (yammie tony)
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I agree. My RPC single is the same way. My buddy had a Bender single on his SX and I had the Psi twins on my old SX. The Bender really moved out of the corners compared to the psi twins. We both have since sold our SX's. I wish I could have got my buddy's sx. It was super clean.
I have never seen a bender pipe like he had on his. At first I thought it was ceramic coated, but on further inspection, it was in fact stainless. Just plain cool.
 
tomseal6 said:
tony. there was a counter balance weight that went on the mag side to better balance the 570 with twin pipes.
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Yep. You are correct. The reason behind that was to dampen harmonics and keep the fuel in the float bowl from foaming and causing a lean condition. Also to extend crank and clutch life as far as I understand it. I believe it was recomended when you started spinning the motor at 8,000 plus.
One thing I noticed when you run the added weight to the fly wheel is that it is night and day difference as far as winding it up. Its way snappier with out it. I think the style of flywheel may affect that too. I have had some with a factory ring gear (without the teeth) style, and some with nothing. So my guess is the heavier oem flywheel was an update?? Im not really sure. Sounds like one of you guys would know for sure.
 
I didn't feel any diff when adding the fly wheel weight. My PSI twins came out of the hole hard. I didn't have any problems beating 700 wildcats back then. I'd come out even with full mod Indy 650's, then they would walk away.

"sould be .030 less then stock" was not the spec I was looking for.
Your a smart guy, slow down and spec out what has been done (all motor mods) and what mods you have done. From that, have a target of what your looking for before wacking anything
 
Thanks for the complement Doc. Yes your right. I'm going to slow down like you said. After thinking about it the last few days, and getting everyones in put on here, I realized I did way too many mods at once. So like I said before Im going to put my timimg back to stock, patch my air box, change the mains to 360/370, and put the 17t top gear back in it because I know my existing clutching works with it.
Yeah, I suppose an actual squish measurement would be alot more helpful. Sorry. lol. My pistons should be here tonight and Im off of work tomorrow so Im gonna measure my squish and see where im at.
Its been a couple of years since I ran my psi set up. I ran them on two different motors. The sled that came with them was a total dog, and the next sled I ran them on was much better because the motor was fresh. I remember making the asumption that the flywheel weight may have had something to do with the lack of snap. So today I was thinking about it and rememberd when I tore the first motor down the ring end gap was .045!!. Cylinder and piston were in spec tho. That was the first sled I bought in 12 years and the guy told me he freshly rebuilt the motor. The pistons and cylinders are .010 over so my guess there was a bit of wear and or the guy re-ringed it with standard rings. So I'm confident that I am wrong about the statement I made regarding the flywheel wieght.
I'll get my measurements and report back.
 
They did add mass to the flywheel on the 90 Exciter. You can also epoxy a lead weight to the float bowls to help w/the foaming fuel issues.

I think the diff between the 2 gaskets is .2 mm. SX-.6, plain Ex-.8. I think it was on the Exciter SX web page.

Everything is a maybe, I read so much chit I can't remeber where. I've forgotten more than I remember.

Get out the solder and check.
 
Lucky7 said:
They did add mass to the flywheel on the 90 Exciter. You can also epoxy a lead weight to the float bowls to help w/the foaming fuel issues.

I think the diff between the 2 gaskets is .2 mm. SX-.6, plain Ex-.8. I think it was on the Exciter SX web page.

Everything is a maybe, I read so much chit I can't remeber where. I've forgotten more than I remember.

Get out the solder and check.
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Thanks for the reply. Thats exactly what im looking for. I hear ya as far as it being a maybe, because I have read so much about these things in the last few years. But dang if I can remember exactly where or what!!! LOL
After I get done typing this Im going to pick up my new pistons and make a stop at the hardware store for some thick solder for my squish test. Thanks again!!
 
I like to shave the skirts about .100", some say .125". Never had a reversion problem. Hint: don't go overboard, you can't put it back.
 
Lucky7 said:
I like to shave the skirts about .100", some say .125". Never had a reversion problem. Hint: don't go overboard, you can't put it back.
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I was going through my RPC tech book and noticed they took 2.5mm of the skirts. Im gonna give that a shot.
I wonder how much weight a guy would have to add to the carbs to be effective? Im still running the rpc single so I dont think i'll have an issue, but just curious.
No worries on yours or anyone elses spelling. I dont judge, as Im not as articulate as I once was.LOL
 
I also thought I heard somewhere that Yamaha changed the compound of the rubber for the intakes to help keep the fuel from frothing in the bowls. I remember something about model year 1990.
 
I'm at the lake tonight thru Mon. but when I get home I'll look for a set of weights I bought years ago from who ever, and never installed. I'll weigh them, and get back to you. I also have a brand new weight ring that goes on the flywheel I bought and never used (I like buying parts!).

Yup, 2.5 MM = .100". Mine likes it, .040" over Wiseco's (warm it up GOOD w/these), PSI lake racer ported, bored carbs, Dial-a-jets, .020" off the head, PSI single, cold air kit. Going to try 600 Vmax carbs jetted to SX specs, and 600 clutches too. Our FB page got me Excited about this sled again. Got PSI twins too, but the single runs great.

Good Luck, John
 
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