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Piston Question
- Thread starter beardo76
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FinnExplorer
Active Member
Depends maybe if it's OEM or aftermarket stuff. Quick browsing for aftermarket pistons(WSM, ProX, Wiseco) tells that all 951 engines use same pistons or they are divided to carbed and di versions. This is total guess but I believe there are some differing part numbers for some parts that are in fact same but just numbered differently depending in which model they were installed in factory line.
But in your case I'd think it fits well, being from 951 di to your 951 di.
But in your case I'd think it fits well, being from 951 di to your 951 di.
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Sportster-2001-951C-Stock
Well-Known Member
There was a change in there somewhere to the porting on the DI, someone mentioned a service bulletin. Not sure if the change was in the sleeve, piston, or both. Can't inadvertently swap DI stuff around b/c it won't run quite right, apparently.
Sportster-2001-951C-Stock
Well-Known Member
If your pistons are undamaged and the clearances are in spec, then ORDINARILY used pistons should be fine especially if not scored.
I've even put scored pistons back in antique 2 stroke motors(no replacements available) before, after cleaning them up with fine sandpaper, new rings properly gaped and they were fine.
The DI engines may have used special coatings on them though, not sure if they were bare aluminum, but if yours spec to a specially coated piston then I'd consider installing new ones.
I've even put scored pistons back in antique 2 stroke motors(no replacements available) before, after cleaning them up with fine sandpaper, new rings properly gaped and they were fine.
The DI engines may have used special coatings on them though, not sure if they were bare aluminum, but if yours spec to a specially coated piston then I'd consider installing new ones.
Thanks for the replies, then pistons have about 20 hours on them if that, .
This is what has happened to me
http://www.seadooforum.com/showthread.php?62857-2004-Sportster-le-di
This is what has happened to me
http://www.seadooforum.com/showthread.php?62857-2004-Sportster-le-di
Sportster-2001-951C-Stock
Well-Known Member
Yes, I recall your post. I believe your engine builder should be making this decision, however, the innards are going to have to match your MPEM map and I don't know what changes BRP actually made to the pistons over the period or if those changes might conflict with the mapping in the 2004 MPEM.
Physically, it might work but mapping can be hardware dependent, especially open-loop mapping strategies such as this one.
If you were to say one piston had .001% more silicon alloy than the other and that's the only difference, then I'd tell you to go for it and put the 2001 pistons in there.
Physically, it might work but mapping can be hardware dependent, especially open-loop mapping strategies such as this one.
If you were to say one piston had .001% more silicon alloy than the other and that's the only difference, then I'd tell you to go for it and put the 2001 pistons in there.
Sportster-2001-951C-Stock
Well-Known Member
Okay, so since BRP changed the sleeve from 6 ports to 5, that could definitely necessitate changes in the injector mapping. Could be they moved the ring-end locating pin on the piston as well, to locate the ring ends in another location in order to avoid having the ring ends snag in the port.
So, if you do decide to try reusing those pistons, then you should look to make sure the ring ends don't land near one of the ports, or inside of the port cutout, that would result in an ugly failure if the ring end was to snag in the port.
Those rings don't spin in their lands, there is a pin in the land that keeps the ring from spinning.
You might consider calling SBT and asking them this most excellent question of yours about piston compatibility, they probably can give you a much more definitive answer.
So, if you do decide to try reusing those pistons, then you should look to make sure the ring ends don't land near one of the ports, or inside of the port cutout, that would result in an ugly failure if the ring end was to snag in the port.
Those rings don't spin in their lands, there is a pin in the land that keeps the ring from spinning.
You might consider calling SBT and asking them this most excellent question of yours about piston compatibility, they probably can give you a much more definitive answer.
Thanks for your replies. I will find out from SBT if the pistons are actually different and report back to close this thread.
Since I have to get my jugs resleeved (around 600 bucks here in Canada) with a 2004 sleeve, i will likely just get new pistons as well for the 'piece of mind' knowing the entire top end was rebuilt.
Thanks again for taking the time to reply. I am an avid sledder and seadoer and this forum plus dootalk are fantastic!
Since I have to get my jugs resleeved (around 600 bucks here in Canada) with a 2004 sleeve, i will likely just get new pistons as well for the 'piece of mind' knowing the entire top end was rebuilt.
Thanks again for taking the time to reply. I am an avid sledder and seadoer and this forum plus dootalk are fantastic!
Guest_User
New Member
other than an exchange from SBT, I`m not sure if you are close to here or not. I`ve had excellent service on yamaha cylinder repairs from here:
http://www.mt-llc.com/index.php
maybe worth a shot to give them a call and see if they can repair your SD jugs...
Sportster-2001-951C-Stock
Well-Known Member
Well there's another point, since you're looking to resleeve.
Assuming the issue(of differences in pistons) does relate to ring end position, then the machine shop may be able to locate the sleeve ports in such a way you can reuse those 2001 pistons, I'm not sure if there's a locating flat to align the sleeve in the casting but if there isn't, or if the machine shop is capable of positioning the sleeve such that the ring ends on the 2001 pistons aren't inside the port then those pistons you have might still work out fine.
Assuming the issue(of differences in pistons) does relate to ring end position, then the machine shop may be able to locate the sleeve ports in such a way you can reuse those 2001 pistons, I'm not sure if there's a locating flat to align the sleeve in the casting but if there isn't, or if the machine shop is capable of positioning the sleeve such that the ring ends on the 2001 pistons aren't inside the port then those pistons you have might still work out fine.
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