Piston Replacement
Moderator: rztom
Piston Replacement
One of my fuel petcock outlets plugged on my 350lc and as a result a piston seized. Once the cylinder was cleaned up it appears to be ok. Just some visual marks that cleaned up after a cylinder hone. However the piston is toast. How do I replace the piston while making sure the piston to cylinder clearance is ok or do I need to bore next size over ?
1973 ct70
1974 xr75
1977 rd400
1981 rd350lc
2002 zrx1200
1974 xr75
1977 rd400
1981 rd350lc
2002 zrx1200
- T.RexRacing
- Posts: 1318
- Joined: Fri Nov 01, 2013 8:34 pm
- Location: back in the hills
Re: Piston Replacement
Measure the bore. Use a bore gauge not calipers. Measure for size,taper and out of round. Then decide. if you don't have a bore gauge buy one if you'll be doing this regularly if not the local machinist should do it for a reasonable fee if not free.
You can pick up a Fowler kit for about $200 USD.
You can pick up a Fowler kit for about $200 USD.
There is only one difference between a madman and me. The madman thinks he is sane. I know I am mad.
Salvador Dali
Salvador Dali
Re: Piston Replacement
I haven't measured the bore.......had a total rebuild 1500km ago. If the bore is good and only need a piston, I guess its just luck that you get a piston close to the proper size to end up within the piston to cylinder clearance values.
1973 ct70
1974 xr75
1977 rd400
1981 rd350lc
2002 zrx1200
1974 xr75
1977 rd400
1981 rd350lc
2002 zrx1200
- T.RexRacing
- Posts: 1318
- Joined: Fri Nov 01, 2013 8:34 pm
- Location: back in the hills
Re: Piston Replacement
Well made pistons vary little from one to another.
There is only one difference between a madman and me. The madman thinks he is sane. I know I am mad.
Salvador Dali
Salvador Dali
Re: Piston Replacement
Quality pistons from the same manufacturer should be interchangeable, especially if from the same production run. How long did the 1500km take?
Red/White US '84, Spec II pipes, Y-boot w/K&N, Fox Shock, Mikuni carbs?
Re: Piston Replacement
You don't rely on luck when fitting an engine with parts. What matters is how much material was removed with the hone and where. Your bore measurements will have to be compared to that of the piston, with recommended clearances from the piston manufacturer.
Rory
2 1984 RZ350s
1985 RZ350
9 1986-1990 RZ350s
2000 ST2
2005 749
2005 749 with 999 engine
2 1984 RZ350s
1985 RZ350
9 1986-1990 RZ350s
2000 ST2
2005 749
2005 749 with 999 engine
- Yellow and Black RZ
- Posts: 379
- Joined: Thu Sep 27, 2007 3:59 pm
Re: Piston Replacement
If it was me, and the cylinder bore is ok, I'd verify what size the piston is and buy the same piston from the same manufacturer.
Would be a good idea to verify size but .25mm is .0098. Pretty tough to have much variation when the tolerances have to be so tight.
With that said pick up some bore gages and eliminate any fears you might have.
Would be a good idea to verify size but .25mm is .0098. Pretty tough to have much variation when the tolerances have to be so tight.
With that said pick up some bore gages and eliminate any fears you might have.
'85 RRZ350 - Hacked.
Re: Piston Replacement
Does anyone know who sells pro-x pistons in Canada ?
1973 ct70
1974 xr75
1977 rd400
1981 rd350lc
2002 zrx1200
1974 xr75
1977 rd400
1981 rd350lc
2002 zrx1200
- Yellow and Black RZ
- Posts: 379
- Joined: Thu Sep 27, 2007 3:59 pm
Re: Piston Replacement
Have you tried PMC? http://www.pmcanada.ca/" onclick="window.open(this.href);return false;2cycle wrote:Does anyone know who sells pro-x pistons in Canada ?
'85 RRZ350 - Hacked.
Re: Piston Replacement
I just tried them but when i start to search I get access denied. will pistons from banshees fit my 1981 350lc and is there specific years that fit ?
1973 ct70
1974 xr75
1977 rd400
1981 rd350lc
2002 zrx1200
1974 xr75
1977 rd400
1981 rd350lc
2002 zrx1200
- two-stroke-brit
- -----
- Posts: 1701
- Joined: Fri Nov 22, 2013 10:49 pm
- Location: Houston texas
Re: Piston Replacement
there is a sticky just about this.2cycle wrote: will pistons from banshees fit my 1981 350lc and is there specific years that fit ?
viewtopic.php?f=15&t=9739" onclick="window.open(this.href);return false;
mark
350LC,Athena 392 big bore,stock porting,swiss cheese air box,stock reeds,spec11 pipes.(now TSA big bore pipes)
She might not be pretty but she will always be a fun ride
1982 YAMA RD350LC
98KDX 220R
1967 TRIUMPH TIGER
2001 TRIUMPH TT600
She might not be pretty but she will always be a fun ride
1982 YAMA RD350LC
98KDX 220R
1967 TRIUMPH TIGER
2001 TRIUMPH TT600
Re: Piston Replacement
Thanks for all of the advice.
1973 ct70
1974 xr75
1977 rd400
1981 rd350lc
2002 zrx1200
1974 xr75
1977 rd400
1981 rd350lc
2002 zrx1200
-
- Moderator
- Posts: 7030
- Joined: Wed Mar 24, 2010 2:20 am
Re: Piston Replacement
Assuming you had matching left and right pistons to start with you might want to consider the weight of the piston being replaced. If you use a different brand/manufacturer, ideally the new piston should be very close to the weight of the undamaged piston or you could end up with a larger than desired weight difference between left and right. If balance is at all important to you.
If you have a damaged bore and need to go up 1 size you can replace just that one piston with the next size up and balance that piston to the weight of the other cylinder's piston. As long as both piston weights are the same (or very, very close) the difference in bore size won't matter. It saves the expense of having to bore and go up 1 size on the undamaged cylinder.
If you have a damaged bore and need to go up 1 size you can replace just that one piston with the next size up and balance that piston to the weight of the other cylinder's piston. As long as both piston weights are the same (or very, very close) the difference in bore size won't matter. It saves the expense of having to bore and go up 1 size on the undamaged cylinder.
Re: Piston Replacement
\Yellow and Black RZ wrote:If it was me, and the cylinder bore is ok, I'd verify what size the piston is and buy the same piston from the same manufacturer.
Would be a good idea to verify size but .25mm is .0098. Pretty tough to have much variation when the tolerances have to be so tight.
With that said pick up some bore gages and eliminate any fears you might have.
Do you mean make a request to the manufacture for a piston as close as the same size as the good piston or buy any 64.50 piston from the same manufacture ?
1973 ct70
1974 xr75
1977 rd400
1981 rd350lc
2002 zrx1200
1974 xr75
1977 rd400
1981 rd350lc
2002 zrx1200
Re: Piston Replacement
I have successfully used Prox and Wiseco of 0.5mm different size in one engine - I guess you won't find more of a mismatch in aftermarket pistons.
(That's what you do as a weekend repair when that bloody Seizco failed and you had a complete used cylinder to swap ... if it weren't for the different piston. But hey, the wish to ride was stronger than the fear it won't work)
It didn't vibrate more - just differently in different rpms.
(That's what you do as a weekend repair when that bloody Seizco failed and you had a complete used cylinder to swap ... if it weren't for the different piston. But hey, the wish to ride was stronger than the fear it won't work)
It didn't vibrate more - just differently in different rpms.
Bye
Martin
Martin