on my 2000 sx600r I think I need to rebuild the topend I'm running 94 , 105 , 116 psi from pto to mag side are these good, bad or ugly compressoin numbers I have always been told even compressoin is the most important thing before I dive into a 300 dollar + repair thought I would see what you guys think
I would open it up (top end) and measure and inspect everything. How many miles on it?
Yes compression numbers may vary for several reasons but should all be within 5% - 10% of each other. I would guess that you will find a small problem once you open it up. Check your reeds, and exhaust too.
Yes compression numbers may vary for several reasons but should all be within 5% - 10% of each other. I would guess that you will find a small problem once you open it up. Check your reeds, and exhaust too.
yamyrider
Active member
94 to 116 is too much difference in compression...it looks like a rebuild of top end.
You need to tear the top end and check pistons, cylinder walls to see what is going on....yes those numbers are ugly
You need to tear the top end and check pistons, cylinder walls to see what is going on....yes those numbers are ugly
thanks guys I thought as much 2700 miles for the record and I just clicked buy it now on a wiseco top end kit if there's anyone out there with problem $320 with $15 for shiping on ebay with microsoft cashback less then $300 in stock shipped out today from kens motor sports
I would recommend oem parts, especially pistons if that is what you bought. I am guessing so by the price. The Wiseco pistons are very good products, but they expand faster than the stock ones which can cause problems if extra tolerance, and warm-up procedures are not followed.
Also, don't order any parts until you measure and inspect. It may change what you order.
Also, don't order any parts until you measure and inspect. It may change what you order.
Ding said:
That's for sure!
I personally won't touch Wiseco's stuff. Kimpex, OEM, Custom Ect ONLY!
Talk to your building about what manufacturer they use, and prefer. Order parts after the Cyl's are inspected.
what problem should I look out for and is the warmup procedure posted any where also I don't understand the why pistons expanding faster hurts the motor could you explain that more
Ding said:
If not enough clearance is given they will seize.
is that ring clearance on the cynlder wall meaing the psitons expand to much rather than to fast or is it the cast jugs expand slower
01sxr700
VIP Member
Those should be Nicasil cyl and cannot be bored out. If I'm not mistaken the pistons only come in the stock size. They say that OEM pistons will last longer and are cheeper. I have Wiseco pistons and ensure that the engine is warmed before riding. Even if u stop for ten minutes let the engine idle for a minute or 2 before riding. When you stop the engine stays warm and the water in the coolers cools off, when you restart you can see the water temp drop 30 deg. right smartly. The Wiseco pistons have a funny rattle to them when idleing so just be warned.
IMHO: Piston to Cylinder clearance needs to be greater than what Wiseco says on the box unless you can ensure that complete warm-up procedures will always be followed. Otherwise the cast cylinder will not expand as fast as the forged piston and could cold seize. If that sled does not have a t-stat (I can't remember on the '00 600 SXR), going slow in powder after heavy throttle (heat) can allow the cylinder to shrink too much. This is not nearly as common, but something to consider. Both of these situations can be overcome by added clearance. However, you do not want to go so high that the piston rocks too much and prematurely wears out. Be sure to check the cylinder straightness and out of round. Also measure everything including ring end gap. Be sure you are within spec. I would go .001 - .002 over on the recommended piston to cylinder clearance.