Changin pistons? 04 rev
- Thread starter rookie23
- Start date
When I did mine, I removed all the cowling and the aluminum bar across the top which gave me full access to the top of the motor. The whole thing takes about 3-3.5 hours. Make sure you put the piston in with the arrow pointing towards the exhaust and make sure the circlips are installed properly as per the instructions. Oh....and most important thing is if your pistons are original...make sure you get every one of the pins in the "uncaged" stock bearings. (I think there are 16 on each bearing but can't quite remember). If one falls down inside the case, you may have to split it to get it out. Cover the case with a rag before pulling the pins in the piston rod. Most likely your aftermarket needle roller bearings will be caged which makes it much easier for when you do it again.
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whats the deal with doo 800s why are u pulling the pistons?
H
HighSierra
New member
There's also caged needle bearings made by Yamaha that will work... a little search over on doo talk will probably find ya the part number and you can go down to the yammi dealer...
Also... You really only need to remove the side pannel (ust to give you some elbow room) to pull the jugs.... It's even easier if you take the RAVES off first...Turn the steering far left and far right, and the steering post will move out of the way to give you ample clearance. Pretty easy to get at even though at first look it seems cramped...
Also... You really only need to remove the side pannel (ust to give you some elbow room) to pull the jugs.... It's even easier if you take the RAVES off first...Turn the steering far left and far right, and the steering post will move out of the way to give you ample clearance. Pretty easy to get at even though at first look it seems cramped...
J
JROD
Well-known member
Decided to do it tonight...
Here's what I found. I am running Wiseco's in an otherwise stock motor with an Aaen pipe/can and Nitrous Express kit. My assumption is the ring somehow turned, grabbed the exhaust port and took the chunk out of the top of the piston.
It was at low RPMs when it all went south and there's no marks on the head but there is on the piston. Cylinder is probably shot. There's a about an 1/8" gouge out of it. Anyone else have a clue what could cause this? Better luck with yours rook!
Here's what I found. I am running Wiseco's in an otherwise stock motor with an Aaen pipe/can and Nitrous Express kit. My assumption is the ring somehow turned, grabbed the exhaust port and took the chunk out of the top of the piston.
It was at low RPMs when it all went south and there's no marks on the head but there is on the piston. Cylinder is probably shot. There's a about an 1/8" gouge out of it. Anyone else have a clue what could cause this? Better luck with yours rook!
R
rookie23
New member
yow...thats ugly! 
when i blew my stock 04 up it took a chunk out of the piston skirt about the size of a golf ball....limped it out about another 2 miles and pulled it apart....no damage to the jugs or anything...only damage was a oiler in the case got closed up....
will be pulling mine down tonight as well to see....didnt hear any noise when it died...thinkin maybe cold seize? any of u guys using the T-stat delete kit?
thanks for the info as well guys!
rook
when i blew my stock 04 up it took a chunk out of the piston skirt about the size of a golf ball....limped it out about another 2 miles and pulled it apart....no damage to the jugs or anything...only damage was a oiler in the case got closed up....will be pulling mine down tonight as well to see....didnt hear any noise when it died...thinkin maybe cold seize? any of u guys using the T-stat delete kit?
thanks for the info as well guys!
rook
R
Rev840
New member
Well this if interesting. I to am pulling my cylinders off my 04 to put in new pistons. Lets just say mine are not stock bore. I have caed bearings in my motor. I suspect Big John can hook you up with caged bearings with no problem. I think he told me he even has them in stock. I pulled my cylinders to update the porting and RKT head and found both cylinders had garfed pistons. A bit to lean in the mids I suspect. opps better add a few jet sizes after the new pistons are installed. It took about 2 hrs to tear down. parts here on Friday to install in 2-3 hrs and ride of Sat.
I think the stock pistons in the 04 also had two small of a pin which wears and evenutally allows the ring to rotate and catch a port. I have one of those to.
I think the stock pistons in the 04 also had two small of a pin which wears and evenutally allows the ring to rotate and catch a port. I have one of those to.
S
sledhead79
New member
definitely a pin that wore and caused the ring to rotate. looks just like my friends that he redid beginning of sled season. his is an 04 with 2600 miles. i was cautious as mine is also an 04 but i bought this sled last year with a new upper end put in it along with the updated rings done by a local dealer. good luck to ya!!
call 1-517-238-5955 he has the caged bearings, pistons, and cylinders, ready to ship, in stock for all brands, cylinders are your choice, nos, or rebuilt all ,with a good core exchange.[i thnk i paid less than $300 for a brand new one with my cylinder exchange] i dropped a few of the cageless bearings in my case, all i did was turn the case upside down, and they came right out.
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jrod that cylinder looked exactelly like mine. i was running 30-40 mph when it went down. we came to the conclusion it was way lean in the midrange. i was always running to hot on the egts in midrange [1260-1300] but when mine blew it was showing 1100'.
Call Kelsey at RK Tec. He has caged bearings for the pistons.
Here is his info:
RK Tek
1245 W. Industrial Park Rd.
Preston, ID 83263
PHONE: 208-852-3221
FAX: 208-852-3228
EMAIL: torqueline@2strokeheads.com
Ditto. Also if you are smooth and patient you can also pull both jugs at the same time with the y-pipe attached. It's a real Mother to get the manifold bolts out of the y-pipe if the jugs are in place. You can also reverse this process when putting them back in, but it'll help to have an extra set of hands to hold em while you guide the piston/rings into the cylinder! I did it this last weekend, so I know you can do it.
