cam19aro86
New member
I have about 7 k on my 99 SRX 600. To my knowledge it has the original pistons and rings. The sled runs great and has good compression. I was wondering if I should freshen up the top end this summer with some new pistons and rings for some preventative maintenance or just leave it alone. Also if I am going to do new pistons, is it necessary to replace the crank seals or should I just do a leak down check? Any I put is appreciated!
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99srxracer
New member
I wouldnt touch it if compression is good and runs good. I have 10,000 orig miles on my 01 srx and runs like day it was new. Im not rebuilding til its time
Rebuild if you want, but do a leakdown test and see what the results say. I'm coming up on 15,000 miles and still trust this sled. Normally I wouldn't trust a 2 stroke with this many miles, but since I bought this sled new and know everything that it's been threw, and that it gets maintained properly, I'm going to see how long she'll go. Of course now that we've talked about this, my next ride may be it's last.
It would be a good idea if you plan on keeping the sled to rering it. Really it needs to be done around 3500 miles if you want it to stay in tip top shape and tune. As some guys will tell you oh they run great and I have 20,000 miles on it, it doesnt run like it did when it was new. The power reduction from the loss of the ring seal and then the piston wear happens over time, so its very gradual. The 2 stroke engine relys solely on the piston and rings to do the work as thats the engines valvetrain. So the piston is subjected to twice the beating the 4 stoke is. The rings wear first and reduce the seal (blow by)and then the piston begins to rock in the bore and this is what wears the skirts.
Sure, it will sound and run just fine but whats waiting to happen is the piston will break off the skirt from rocking in the bore and then the engine will be trash in short order, usually blowing out the case bottom from a pressure crack.
If 2 strokes would go high miles with no piston ring changes we'd have 2 stroke cars with the great power to weight ratios a 2 stroke offers, but you cant get away from that a 2 stroke relys solely on the piston/rings to do all the work. In this thread alone you have 2 guys telling you how great they run and how you dont need to do anything, but if you put a leak down test on their engines they would fail. The other big misconception is and as said "it has great compression yet", well ya,.. compression is just the measure of how fast the cylinder can build pressure but to check a rings condition, you need to do a leakdown. Thats what measures the rings ability to seal, so what youd measure is how long can you hang onto that pressure, not what the rapid build up is. If the 100psi leaks down in seconds the rings are not sealing good,=-blowby.
Just the other day there was a thread of a 02 srx with 11,000 miles that broke off a skirt and sent it down into the crankcase, this is what happens when the piston rings wear and the piston becomes sloppy in the bore, it WILL break off the skirts sooner or later, I promise you.
its your engine do with it as you deem is what you need to do.
Sure, it will sound and run just fine but whats waiting to happen is the piston will break off the skirt from rocking in the bore and then the engine will be trash in short order, usually blowing out the case bottom from a pressure crack.
If 2 strokes would go high miles with no piston ring changes we'd have 2 stroke cars with the great power to weight ratios a 2 stroke offers, but you cant get away from that a 2 stroke relys solely on the piston/rings to do all the work. In this thread alone you have 2 guys telling you how great they run and how you dont need to do anything, but if you put a leak down test on their engines they would fail. The other big misconception is and as said "it has great compression yet", well ya,.. compression is just the measure of how fast the cylinder can build pressure but to check a rings condition, you need to do a leakdown. Thats what measures the rings ability to seal, so what youd measure is how long can you hang onto that pressure, not what the rapid build up is. If the 100psi leaks down in seconds the rings are not sealing good,=-blowby.
Just the other day there was a thread of a 02 srx with 11,000 miles that broke off a skirt and sent it down into the crankcase, this is what happens when the piston rings wear and the piston becomes sloppy in the bore, it WILL break off the skirts sooner or later, I promise you.
its your engine do with it as you deem is what you need to do.
superfan75
New member
Well put Mr Viper. That's how the shop where I go explained it to me when I used to race moto cross. I couldn't see why I needed to do a top end when the bike ran good. When I finally tore the engine down to my surprise the piston had cracks on both sides going from the top to bottom. I couldn't believe how lucky I was and from that point on I took care of the pistons and rings on a regular maintenance schedule and I never had any trouble with my bikes for all the time I was racing. These engines last much longer than moto cross bikes, but I would think its a good idea to change the ring before some really bad happens. Rings are a lot cheaper than a blown engine.
TopGunnSrx
New member
I put new pistons and rings in mine around 7k miles, it didnt run bad and everything was still good but as the miles went up our rx1 would start to be harder to beat. With the fresh components it was back to leaving the rx1 in the dust. Ive since got about 8-9k on the rebuild and it could use a freshen up again.
Does it need it? Probably not, but IMO you'll be able to tell that you did.
Does it need it? Probably not, but IMO you'll be able to tell that you did.
This is why I'm torn on redoing mine. My compression is still around 120-123 between all three, using the same guage I've always used. My sled passed a leak down test 3 yrs ago with over 12,000 miles. Much the the mechanics suprise, and mine. I've noticed no lose in power as it will still GPS mid teens on a lake with packed snow. I still beat every sled I should beat and some that should easily beat me, from holeshot to top end.
Would it be smart to re-ring? yes. But there's that little voice the says "let's see how long it'll go". Am I the smartest person here?………NOPE !!!
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TopGunnSrx
New member
Totally your call, we all know these engines are capable of high miles on original equipment nothing new. Its cheaper and easier to replace parts on an undamaged engine rather than gamble and possibly ruin the whole thing. Its only a matter of time, there's no PROS that come from saying you have high miles.
Roll the dice........
Roll the dice........
LOL, your right on the money. Think I'll redo it…………next fall.
cam19aro86
New member
Well I have decided to do new rings for sure. Is there any need to redo the pistons if they look like they are in good shape?