First time replacing rings, need advice!

mountain_man

mountain_man

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Oct 3, 2009
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Location
Indiana
Hey guys, hit 5500 miles on my 2001 srx 700, decided to refresh the top end this year, everything is going smoothly as far as disassembly is concerned. I need some advice though, 2 cylinders look great, but the mag cylinder not so good. someone has been in this motor already (bought the sled used from the dealer, have put 2200 or so miles on it since purchased) not sure who was in there, but it looks like a needle bearing came loose at one point in its life. the top of the piston is ok, no marks on top, the side is slightly scored, the head has indents from what looks like a blown needle bearing, and the jug has some slight scoring and coating wear. the sled was running great before, the plugs all the same color, and the heads were all the same color. didnt think to check compression before unfortunately. it doesnt appear that the rod bearing is bad. my question is this, should i have the cylinder machined and recoated and replace the piston, or do you think i would be ok honing and replacing the rings? it ran like a top before, i was just refreshing for maintenance...

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IMO:

The damaged cylinder should be repaired or exchanged [Millenium does exchanges]. Any time you have cylinder damage above the exhaust port that you can catch your finger nail on it needs to be repaired. I would just reuse the cylinder head, replace the marked up piston and replace the rings.
Have a good look at the rod for side play ect on the cylinder that was damaged.

Bob
 
Thanks Bob, I think I have found a suitible replacement, Do you know if cylinders are the same for a 2000 and 2001 srx? The one in question comes from a 2000 and includes piston...
 
mountain_man said:
Thanks Bob, I think I have found a suitible replacement, Do you know if cylinders are the same for a 2000 and 2001 srx? The one in question comes from a 2000 and includes piston...
Click to expand...

Yes the 2000/01/02 cylinders should all be the same. I would just ensure that there are no sharp edges on the damaged cylinder head. A little wet sanding with 400 grit will do the trick.

Bob
 
I don't like the way your wrist pin, and bearing looks. It looks like it's been run pretty hot.
 
I have seen those marks in the head a couple of times before myself and mine was caused from a lean burndown,I'd say either a piece of ring did the damage or a piece of piston banged around a bit.I inquired about running heads with those kinds of indents in them and was told that hot spots could occur in those areas so it was best to replace them.If your getting the cylinder and piston from the 2000 get them to throw in the head too.
 
Found another cylinder head from a 1999 srx that looks good, will this fit a 2001? looks identical...
 
Heads are slightly different volume from 1998/99 to 2000 + up.
1998/99 = 8DN-00 slightly more volume
2000 + up = 8DN-10

Although the 98/99 heads will bolt up it would be better to stay with correct head.
If you are going to spend the cash you should also replace all the piston pins + wrist pin bearings as well.

Bob
 
yes 98/99 cyls and heads will physically fit but porting and head ccs are different.

i have a good 2000 cyl and head i'd probably sell. i was saving them for spares but x-mas is coming so pm me an offer, who knows might let em go
 
thanks stagg, already ordered the parts though.... glad i found this now instead of blowing the motor on the trail somewhere, now i just have to be patient and wait for my parts to arrive... thanks everyone for the help!!!
 
Just finished putting my engine back together... no leftover parts! woohoo! New mag cylinder and head and piston, all new rings and pin bearings and pins, reeds look good yet, carbs nice and clean, thanks mr powervalve for fixing my valves! new powervalve cables... can't wait to fire her up tomorrow! what ratio of pre mix should i run for the break-in?
 
no need for pre-mix.Make sure you bleed the system to get the air out.Then when you start her up pull the oil line full open for a few minutes to ensure there is a good delivery of oil getting thru.She will smoke and that is a good sign. Pre-mixing will lean you out as the oil pump is pumping oil also into the gas and motor.I just bleed the oil lines on both my re-builds this year and have no issues at all.
 
i did not remove the oil pump or lines at the fuel pump, just my fuel lines at the carbs, shouldn't have air in the oil system, right?
 
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