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Pistons

A
Jan 19, 2008
234
9
18
40
what is everyone running for pistons in there pros. rebuilding my 800 keeping stock bore. whos piston is best to run? thanks!!
 
R

rmscustom

Well-known member
Jun 8, 2010
2,181
1,801
113
I went RKT after confirming my cylinders were the correct size. Drop in kit, great boost in power. 700 mountain miles so far.
 
A
Jan 19, 2008
234
9
18
40
are the wossner pistons from rk tek really different from bmp? they are only 300 on the bmp site. and 350 from rk tek?
 
A
Jan 19, 2008
234
9
18
40
I went RKT after confirming my cylinders were the correct size. Drop in kit, great boost in power. 700 mountain miles so far.


my cylinders should come back the correct size, i shipped the mono block out to millennium to get stripped and replated. did you only replace just the pistons? and notice a difference in power? or did you also do the head?
 
U
Nov 29, 2007
454
172
43
55
pistons

I went with the BMP kit. I pick wossner pistons over wiseco pistons

I tried to install a BMP kit the wrist pins were to long couldn't get the c clip in, took them back installed MNTKT kit have 450 miles on it now. Both kits are equal quality both are nice pieces the BMP pistons are a little lighter than the wsieco.
 

Merlin

Well-known member
Lifetime Membership
Oct 7, 2004
1,183
300
83
Medicine Hat, AB
my cylinders should come back the correct size, i shipped the mono block out to millennium to get stripped and replated. did you only replace just the pistons? and notice a difference in power? or did you also do the head?

The machine shop will likely shoot for stock bore specs. which may or may not provide the correct clearance for the Wossner pistons. As a rule of thumb you should measure the pistons that you intend to use & then request the finished bore size that you would like in order to end up with the desired PTCW clearance. Once you receive the cylinders from the repair shop you should measure the bore to confirm that you have received what you asked for.

Trusting that new pistons are the exact dimension printed on the box is a mistake.

Trusting that the repair shop has provided you with bores that are the correct size & quality is a mistake.

Whether you can do it yourself or have to pay to have a machine shop to do it for you, taking the time to blueprint during assy. will simply add to the possibility of a successful engine build & give you a piece of mind that there is one less thing to worry about.
 

tinkerjohnson

Well-known member
Premium Member
Dec 12, 2008
1,168
262
83
Southern utah
my cylinders should come back the correct size, i shipped the mono block out to millennium to get stripped and replated. did you only replace just the pistons? and notice a difference in power? or did you also do the head?

The drop in kit requires a different head because of the port timing change, rkt has direct replacement pistons that can use ether stock or aftermarket head I believe the head is a key component to making them run (more compression)
 
R

rmscustom

Well-known member
Jun 8, 2010
2,181
1,801
113
are the wossner pistons from rk tek really different from bmp? they are only 300 on the bmp site. and 350 from rk tek?

Wossner makes Rkts pistons to his specs and he has 2 different ones, the drop in kit pistons and the direct replacement pistons.

my cylinders should come back the correct size, i shipped the mono block out to millennium to get stripped and replated. did you only replace just the pistons? and notice a difference in power? or did you also do the head?

I did the drop in kit which is the head and pistons that change the port timing.
 
J

jeepin270

Well-known member
Aug 27, 2009
552
166
43
Maine
Does anyone know if there is any difference between bikemans direct replacement pistons versus rkt's direct replacement?
 
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