Piston ring compressor

jotajoe

jotajoe

Hero member
Location
Warwickshire UK
Hi ,

I have a 79 BMW R100 with a cylinder off and it's time to put it back on !

I want to make a home made ring compressor and just wondered if anybody has trod this route before and can make any smart suggestions ! I don't want to scratch the piston. The Piston is big ! as it's a 1000cc bike. The piston is sat wearing it's rings and I need to slide the cylinder over the top so the compressor gets trapped...That's why I don't want to use a car one..I'd have to wreck it to get it off..

I'd buy one but they only seem to be available for top side..and i don't want to break the rings !

t i a

joe
 
Joe,
Attached a photo showing the method I use on the Laverda engines.
Buy a small sheet of nylon, approx 2-3mm thick.
Cut a strip wide enough plus 5-8 mm to cover all the rings.
Regular old hose clamp.
Install as shown.
Tighten up fully and then back off 1/2 turn.
Support the bottom of the piston with lump of wood or similar
position, give barrels a smack with the heels of your hands
el presto

HTH
Red
 

Attachments

  • Barrels going on.jpg
    Barrels going on.jpg
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I use a similar method to Red, although I use thin brass sheet I get from my nearby model shop, apply a little oil to the brass sheet, and the rings/piston slides right in. Then just undo the hose clamp and remove.

There are motorcycle specific piston ring compressors available that do come apart, but the brass or nylon sheet works just as well and is much cheaper.

Paul LeClair
 
I have used the same method as Red and Paul, but have you tried borrowing from your local bike shop?

The shop owner and I have known each other for a couple of decades now and despite the "just bring em back" I find a four pack of beer for the guys is always appreciated.

Maitland.
 
Same for me. I use anodised alu strip (B&Q - nowt special), anneal it and bend it around whatever piston you are working with. After annealing there is no springback, so it tends to stay where you want it.

The male chamfer on the top fits up inside the female chamfer on the liner and stops the ring pinging out into that open area. HTH, Hag.

Lav%20Ring%20Compressor.jpg
 
Maitland said:
I have used the same method as Red and Paul, but have you tried borrowing from your local bike shop?

The shop owner and I have known each other for a couple of decades now and despite the "just bring em back" I find a four pack of beer for the guys is always appreciated.

Maitland.
Click to expand...

Hmmm But beer is precious  :P
 
redax5 said:
Joe,
Attached a photo showing the method I use on the Laverda engines.
Buy a small sheet of nylon, approx 2-3mm thick.
Cut a strip wide enough plus 5-8 mm to cover all the rings.
Regular old hose clamp.
Install as shown.
Tighten up fully and then back off 1/2 turn.
Support the bottom of the piston with lump of wood or similar
position, give barrels a smack with the heels of your hands
el presto

HTH
Red
Click to expand...

This I likes very much as the Nylon won't damage the pistons or the bore...That's the way I'll do it ,,Cheers

joe
 
I'm presuming the BMW barrels have a slight taper at the bottom.

You can get by without a compressor.

Make sure the barrel and piston are perfectly straight. Ease the barrel down the studs and squeeze the rings with your fingers, one at a time. Use pressure on the top of the barrel to slowly slide it down over the piston.

Oil helps of course.

Make sure the barrel and rings are meeting uniformly.

It can take a bit of time and patience but its how I do it on the guzzi.

Just an alternative.

Rod
 
Morizzi said:
I'm presuming the BMW barrels have a slight taper at the bottom.

You can get by without a compressor.

Make sure the barrel and piston are perfectly straight. Ease the barrel down the studs and squeeze the rings with your fingers, one at a time. Use pressure on the top of the barrel to slowly slide it down over the piston.

Oil helps of course.

Make sure the barrel and rings are meeting uniformly.

It can take a bit of time and patience but its how I do it on the guzzi.

Just an alternative.

Rod
[/quote

Nothing to be lost in trying...cheers I'll let u know how it goes !

joe
Click to expand...
 
installing cylinder onto a BMW boxer is a doddle, I have done a few in the past, the studs will support the cylinder very nicely as you install, no need for a ring compressor, your fingers and the taper will do it easilly.I am slightly worried about this,since you seem (by your own actions) to need to ask, it must be the most easilly installed cylinder piston arrangement on any motorcyle, with engine in chassis or on bench, just go for it.It you want something tricky try a 16 litre Hercules engine from a 1942 Diamond T 981
CLEM
 
CLEMTOG said:
installing cylinder onto a BMW boxer is a doddle, I have done a few in the past, the studs will support the cylinder very nicely as you install, no need for a ring compressor, your fingers and the taper will do it easilly.I am slightly worried about this,since you seem (by your own actions) to need to ask, it must be the most easilly installed cylinder piston arrangement on any motorcyle, with engine in chassis or on bench, just go for it.It you want something tricky try a 16 litre Hercules engine from a 1942 Diamond T 981
CLEM
Click to expand...

I have done it before Clem..and the rings were brand new and  I couldn't manage to squeeze em ! Must have puny digits ! Ok I'm gonna go for it..break the pain barrier and get the job done! Maybe alot easier now the rings have some use.

cheers

joe
 
Joe,
I did this last week! Used plastic cover of ringbinder folder cut up to form strips inside hose clamps. Oil 'em up..slipped on nicely...I did not use the wooden blocks Red mentions. Obviously you need to keep the barrels level...don't force them down unduly. Outside 2 first..easier if most of the studs are removed so you can access...especially true when you come to fit the middle one.There is not a lot of room and what with oil things get a bit slippery...careful to ensure the strip of plastic is square all round and compressing all rings. I had my son hold a spanner on the large nut on the generator end of the crank...you don't want the pistons going south as you are patting the barrels down, do you now?!
Nick7
 
we used the alloy from coke-tins. worked quiet well if you bent the top around so it does not slide between the piston and the barrel... :D

But Red's way with the nylon/teflon sheet is the best, as it produces no scratches at all.

 
Nickdav,
Joe is talking about a BMW boxer here, not the finger crushing, cant see for studs, Laverda triple jobby.
any way well done for getting your pots back on your Jota,your copper head gasket will be delivered at least three weeks later than you need it, just so it still feels like a real Laverda part.
CLEM
 
CLEMTOG said:
Nickdav,
Joe is talking about a BMW boxer here, not the finger crushing, cant see for studs, Laverda triple jobby.
any way well done for getting your pots back on your Jota,your copper head gasket will be delivered at least three weeks later than you need it, just so it still feels like a real Laverda part.
CLEM
Click to expand...

Clem, I have done the Beemer before and although it was about 5 years back I do remember it was tough holding the rings tight together..I don't mind asking a "silly" question if it helps me avoid making silly mistakes and lets face it there are umpteen ways of making omlettes...There is alot of experience and knowledge on the forum which I highly value and respect and if one of the guys out there has a clever way of approaching a task well, I ain't too proud to ask for advice.

As Einstein said..Nobody knows everything about anything !!

Cheers to all the guys for some good advice and tips

joe
 
There is no doubt about it, piston ring compressors will make this job on your boxer,(or a Laverda) a lot easier,on the Laverda, it will make the job reasonable easy to complete, and without, virtually impossible, on the boxer a compressor will still make life easy, but without, you can still do it.

What bore size is your BMW? I realise that my posting could be taken as being a little harsh, not that this was intended, so to make amends,and as long as you are in UK or Europe, I will happilly lend you a compressor, I just need to know what size and your postal address.

CLEM
 
CLEMTOG said:
There is no doubt about it, piston ring compressors will make this job on your boxer,(or a Laverda) a lot easier,on the Laverda, it will make the job reasonable easy to complete, and without, virtually impossible, on the boxer a compressor will still make life easy, but without, you can still do it.

What bore size is your BMW? I realise that my posting could be taken as being a little harsh, not that this was intended, so to make amends,and as long as you are in UK or Europe, I will happilly lend you a compressor, I just need to know what size and your postal address.

CLEM
Click to expand...

Cheers Clem, No worries at all.....I do tend to think out loud on the forums I'm on...so I probly sounded like a dozy plonker Lol !!

I'm going to Man up and have a go at it tomorrow...Thank you for your very kind offer...If I get stuck I'll ask your help further ..!  It is a 1000cc bike and it's on its first oversize..I have a vernier to measure the bore...

KInd regards,

Joe

ps I'm sure we have spoken/dealt with eachother in the past via ebay..I'm Swiftminnion..
 
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