pete72
New member
hey guys. working on a rebuild and am using spi piston and rings. rings don't have a mark on them so not sure which way is suppose to face "up". ring has a slight convex to it and i would think that would be the top. anyone know? ps these are single ring pistons
Throttle Junkie35
New member
The slightly convex or tapered side goes up
pete72
New member
thanks throttlejunkie. i figured it out by trying both ways. they will only fit one way. my error. all back together now and runs great. full rebuild top to bottom on an 87 indy 400. gonna be my new ride this year.still haven't found any yammies i can afford
Throttle Junkie35
New member
Im glad you got it handled. Those old indy's are cool sleds, but your going to miss your Exciter after a few miles. While the front suspension on the Indy really sticks in the corners and takes care of the bumps, the rear skids are pretty harsh and the indy seat is something like a brick where the Exciter had a much softer seat.
I had Polaris', Cats and of course Yamis from the same era (still have a 91 Eltigre EXT as well as my Exciters) and I would take a properly set up Exciter, Phazer or SRV for anything over a 50mi ride over any brand from that time frame.
Good luck with the rest of your summer projects. Soon we will complaining that its too cold to work on sleds. LOL
I had Polaris', Cats and of course Yamis from the same era (still have a 91 Eltigre EXT as well as my Exciters) and I would take a properly set up Exciter, Phazer or SRV for anything over a 50mi ride over any brand from that time frame.
Good luck with the rest of your summer projects. Soon we will complaining that its too cold to work on sleds. LOL
pete72
New member
i won't miss the fuel mileage tho! the Indy has updated xtra 10 and many say its a great skid with fox rebuildable shocks and nice p85 clutches all refreshed. had some nice sloppy steering too till i replaces all the heims. these are good for 85-90 mph and i just cruise wooded trails anyways. getting 14 plus mpg will make up for any regrets. i'll have another Yamaha before too long. just got a good deal on this. im alway looking for another ride! can't have too many!
Throttle Junkie35
New member
Ya, the fuel mileage isnt all that great on the Exciter, not wonderful, but not too bad considering the size/age of the sled though. If you want a real gas hog, the srv is probably the worst and to make matters worse, it has a fairly small tank to boot.
Sounds like you have a nice project going on and the Xtra-10 should help the old 400 quite a bit. Although I would think 85 would be pretty optimistic for a 400 I think you will have a nice quick sled. It looks like the Indy 400 stock has about 62hp and if you add a pipe your around 68hp. Your Ex570 had 77hp in stock trim so I guess there will be a trade off with HP vs mileage. Its always hard to get the best of both worlds. None the less I would think your indy would be a nice all around trail sled.
Sounds like you have a nice project going on and the Xtra-10 should help the old 400 quite a bit. Although I would think 85 would be pretty optimistic for a 400 I think you will have a nice quick sled. It looks like the Indy 400 stock has about 62hp and if you add a pipe your around 68hp. Your Ex570 had 77hp in stock trim so I guess there will be a trade off with HP vs mileage. Its always hard to get the best of both worlds. None the less I would think your indy would be a nice all around trail sled.
pete72
New member
it should work out decent. your right about finding the best of both worlds. i made a short video of it running after my rebuild if your interested in seeing. all stock just.010 over
Throttle Junkie35
New member
Post it up!! 
pete72
New member
not much of a video but here it is. she's pretty smokey with summer temp and added oil to the fuel. come on winter!https://www.youtube.com/watch?v=SNKVYJm7fRc
Throttle Junkie35
New member
Sounds good and looks good. Nice job.
pete72
New member
thanks throttle junkie35 just finished modifying the primary clutch tools i made for the comet 108exp i had on the exciter. i was hoping not to have to but is what it is. i have 2 new factory Polaris belts both are too small in width:>( 1 5/16 not 1/3/8 so need to shim. seems there is a very huge tolerance in belts.
Throttle Junkie35
New member
You may want to check with a polaris guru on the belt. I heard of different OEM part numbers with seemingly the same dementions but are actually different.
pete72
New member
wish that was the case here. i have 2 belts and both measure the same. one is a parts unlimited 1105 and the other is a factory Polaris belt with correct numbers for my application and both measure 1 5/16+. i ended up removing 2 shims and ended up making 2 new very very thin shims to get the clutch marks for balancing realigned. i still had to "clock" my spider 1 tower over to get the alignment. Polaris says its ok to clock the spider if needed to gain realignment and will not affect the overall balance. should be good to go now. i think the only way i would ever be satisfied would be to go to the dealer and measure a new belt till i found one in spec.just one of the pit falls of ordering online i guess. lets face it the average rider never bothers to shim for there new belt. i know i never did till i got serious and wanted stuff as right as i could get it thanks to these great forums.