Front and rear pistons?
- StormyRob
- Posts: 1565
- Joined: Sat Nov 07, 2015 7:33 am
- Location: Northern Ireland. The place of legend
Front and rear pistons?
Need to replace a rear piston to have a second engine.
Had a look and seems the front and rear have different part numbers. I thought they would be the same size and dimensions etc. Is that incorrect?
Had a look and seems the front and rear have different part numbers. I thought they would be the same size and dimensions etc. Is that incorrect?
If you don't try you never know if you can do it.
Re: Front and rear pistons?
I've always thought that they were the same.
And the rings, are they different part numbers as well?
The pistons are very cheap though, std Honda ones, that is.
But whenever I've got that far into an engine I fit high comp ones, bit more spenny but lots more fun....
And the rings, are they different part numbers as well?
The pistons are very cheap though, std Honda ones, that is.
But whenever I've got that far into an engine I fit high comp ones, bit more spenny but lots more fun....
It's not falling off, it's an upgrade opportunity.
- StormyRob
- Posts: 1565
- Joined: Sat Nov 07, 2015 7:33 am
- Location: Northern Ireland. The place of legend
Re: Front and rear pistons?
Rings are the same part number. Yea they are about 25 quid. This engine is going into another bike at some point, not my main one so wont be getting the hi-comp ones...yet. I know of a set for about 150 or so used but just haven't made the decision yet as I cant find cams anywhere in the world for anything reasonable. I am hoping I get lucky some day
I would nearly gamble on the pistons being the same. Just cant understand the number difference.
I would nearly gamble on the pistons being the same. Just cant understand the number difference.
If you don't try you never know if you can do it.
Re: Front and rear pistons?
Thinking about it they will have oil drain holes in different positions, so are cylinder specific.
It's not falling off, it's an upgrade opportunity.
- StormyRob
- Posts: 1565
- Joined: Sat Nov 07, 2015 7:33 am
- Location: Northern Ireland. The place of legend
Re: Front and rear pistons?
Ah. Fair enough. Good thinking and will not gamble on one then!
As you say cheap enough. Fowlers in the morning it is
As you say cheap enough. Fowlers in the morning it is
If you don't try you never know if you can do it.
Re: Front and rear pistons?
...mumble mumble.. this should mean the cylinder are installed differently...
In other words: consider the vtr engine like 2 separate engines of 500 cc.Logically each one should have the same piston and components. If it don't, this is because some other part (which one? boh .. may be the cylinder)of the engine is not completely rotated of 180 degrees, then it needs a differrnt piston to compensate
Re: Front and rear pistons?
The piston pin's offset should be different.
Re: Front and rear pistons?
There isn't any piston offset. This isn't a De saxe design.
The engine's rotation means that oil drain holes need to be in the right place so that oil drains into the back of the ring grooves after it has been flung off the crank during rotation.
The engine's rotation means that oil drain holes need to be in the right place so that oil drains into the back of the ring grooves after it has been flung off the crank during rotation.
It's not falling off, it's an upgrade opportunity.
Re: Front and rear pistons?
Normally every Honda pistons have a pin offset, due to friction and vibrations reduction.....now I'm not sure for this in particular but I'll verify on pistons I have at home.
Other difference should be, as written before, on oil draining holes.
Other difference should be, as written before, on oil draining holes.
Re: Front and rear pistons?
You could be right, I've never actually measured any. It'll be interesting to see.
It's not falling off, it's an upgrade opportunity.
Re: Front and rear pistons?
As I supposed: piston pin offset is different (near to 1mm)
Piston one
Piston two
Piston one
Piston two
Last edited by Red3446 on Thu Oct 05, 2017 12:32 pm, edited 1 time in total.
- StormyRob
- Posts: 1565
- Joined: Sat Nov 07, 2015 7:33 am
- Location: Northern Ireland. The place of legend
Re: Front and rear pistons?
Thank you very much for that clarity. Do not think the question had been asked before
If you don't try you never know if you can do it.
- freeridenick
- Posts: 1580
- Joined: Fri May 23, 2014 1:30 pm
- Location: Derbyshire
Re: Front and rear pistons?
Do you need a piston? I've got at least one you can have.
Re: Front and rear pistons?
Good info, well done for the evidence, too.
It's not falling off, it's an upgrade opportunity.