Exciter SX Piston

thefullmonte

thefullmonte

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I know a person could get either OEM or Wiseco, but does anyone know the specs on the piston cutout to do it yourself? Thanks
 
Lucky7 wrote something about wiseco piston mod in another thread here. Check with him for more details. What i heard sx pistons and wiseco are practically the same.
 
I never heard of an Exciter SX piston cut out. The 84 PHAZER SX had a modification where the piston was cut out and I do have the instructions for that. Jeff Wurl
 
Bender started it I believe. I also have found the spec for the Phazer via Dyno Tech. Actually had a set in a 95 Phazer I used to have. Worked really well.

Same concept for each. Change the intake port timing by modifying the piston. Bender used/developed it on his race motors and then Yamaha used it on the Exciter SX. Can be used on all exciters. Wiseco makes one that is similar, but not quite as aggressive. I was just looking for the measurement if anyone wants to do the cutting themselves.

I was going to tear into a motor, but turns out I don't need to. Still would be nice to have the info.
 
Exciter sx pistons are the same as std exciter pistons. They even have 82m cast inside them even though they have their own 8ay part number. The difference was in the cylinder porting itself and the smaller headgaskets.
 
Now I'm confused. Thanks for the info as that's news to me. I thought the wiseco pistons were a copy of the SX pistons which have a cutout. I thought the piston was the difference and could be used in all older exciters. I didn't realize the porting itself was different. I must have had it backwards.

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OK, then what the heck is in that motor in my 88? Where did that cutout come from? Someone did an awfully nice job on it regardless. :o| Now I'm really curious. :dunno: Now I want to tear it down to see what it is. Lol
 
Probably a Wiseco after a rebuild or something. As previously suggested check out excitersx.com not alot of traffic, but there is some good info and links there.
 
I do appreciate all the info guys. ;)! I guess I was very mistaken. Going from past experience from the Phazer SX pistons I thought there was a piston mod. And after seeing these pistons in one of my sleds I made a poor assumption. I thought I had read somewhere that Bender used to cut his pistons in the old Exciters and that is what inspired the SX. Not sure if that is true. I didn't realize that Yamaha actually changed the porting and not the piston cut.

That being said that is what these forums are for. Learning and sharing. So, again thanks to all of you.

As far as ExciterSX site. Everyone always recommends that site, but I just have never had much if any luck finding anything over there. :dunno: The search function just doesn't like me.
 
So what was the picture you posted of?? Is it an Exciter?, Phazer?

On my motor I cut .100" off the skirt to change the intake opening/closing events of the motor. I did this on several motors (Ski Doos, Yamahas) that I rebuilt (if it comes apart in my garage it gets ported). Always worked good for me. More of a top end mod. I looked back though old threads, and saw where Toy Doc recomended .125" off the skirt to another member.

I was more adventurous back then. I love the die grinder. Never had a problem w/any motor durability.

I always completly warm up my sleds, especially motors w/Wiseco's (forged pistons) many who complain about them lite em up, and go rippin cold, only to destroy the motor. Forged pistons in any application are fitted looser, and need the heat to expand to fit the bore. I learned this the hard was back in the 70's.

I better stop this rambeling.
 
Lucky7 said:
So what was the picture you posted of?? Is it an Exciter?, Phazer?

On my motor I cut .100" off the skirt to change the intake opening/closing events of the motor. I did this on several motors (Ski Doos, Yamahas) that I rebuilt (if it comes apart in my garage it gets ported). Always worked good for me. More of a top end mod. I looked back though old threads, and saw where Toy Doc recomended .125" off the skirt to another member.

I was more adventurous back then. I love the die grinder. Never had a problem w/any motor durability.

I always completly warm up my sleds, especially motors w/Wiseco's (forged pistons) many who complain about them lite em up, and go rippin cold, only to destroy the motor. Forged pistons in any application are fitted looser, and need the heat to expand to fit the bore. I learned this the hard was back in the 70's.

I better stop this rambeling.
Click to expand...

I don't think you are rambling. Myself and others really appreciate the information. ;)!

The picture I posted is in my 88 Exciter. It just looks so professional I thought it was bought that way. Not sure what it is :dunno: Sure runs good though.
 
I thought it looked like an Exciter cylinder... the port layout, very nice. If the motor goes down I would definetly copy that skirt profile. I've seen other motors w/ that same cut, but can't remember... How is the bottom end performance?? Do you need a high engage :postwhore ment speed?

When I worked at Engine Engineering at Ford ( I was a nobody) an older draftsman taught me a trick with heavier construction paper for copying port layout. Shape it like a cylinder, the same height, then tape it together in the bore of the cylinder to be copied. Position it w/tape, then carefully run your finger around the ports to get the shapes. Remove it and cut it out w/an exacto knife. I reinfoced mine w/masking tape. Then put macinist's blue on the cylinder to be modified, tape it in place. Sllde in the template, position, and tape it in place, then carefully scribe the layout. This is how I copied my friends PSI porting. Not CNC, but it works. Use this method to recreate that piston cut.

It's similar to the Race Logic templates.

I know I type to much. :postwhore
 
The only time I got to use it last year was out in the Black Hills. So I had it clutched for that altitude. However, I didn't feel at any time that it needed a higher engagement. That said, I am more of a mountain rider and tend to favor a low easy engagement. Seemed to run real strong though. Took it through more snow than any short track probably should have been. lol Although, not always successful. :rofl:

The sled is actually for sale. I hate to do it, but can only afford to have one. If it didn't sell I would be real tempted to tear it down just to get the specs on that cut out.

And again, you are not typing too much. You are sharing some very useful information and I do appreciate that. The construction paper trick is genius. ;)!

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IMG_0481.jpg
 
Ya, we used to always cut the intake port of the piston. We also increased the flange to accept 44 mm carbs. That was the ticket on the ole Exciter. If i remember PSI twins or DG single pipes. Have fun. Al
 
When you do a round intake cut (Phazer SX piston) on a exciter, the intake window is open to long and it will push your fresh charge of air / fuel back out the intake and not into the top of cyl.

Most piston mods from a reed motor to a piston port motor are not the same. With a reed intake, it stops back flow with the reed. Piston port stops it with piston intake skirt. Thats why you do a flat cut, and not much of one
 
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Thanks for the clarification on that. It looked radical for a piston port engine, thats why I was curious about the low end power. I thought it might make the skirt weaker too.
 
EEE, then ROB, PDC, BLDG 3, after that WHQ... Now the back yard.

Did you know Tiny, Locker, Speight, or Fed man?
 
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