Tricks for getting the pistons into the cylinders on a 4 cylinder?

[jay_kent]

Going to put the cylinders back on the bottom end tonight and was hoping that someone has a trick that would make this go easier. Its a cb650 sohc.

Just wonder what other people have done when assembling a four.

 

[teazer]

You can do it by hand but it's much easier with piston ring compressors. Don't need expensive ones though.

That crank is two up two down right? That means getting one pair started at the same time and then slide the second pair in. You have to be patient and diligent.

A couple of things make life easier. Get something for the pistons to rest on so they don't tip over and mover around. You can get something fancy machined up or two truips of steel or aluminum for each piston will do the job.

An alternative is to hold the barrels still and push the pistons in. Start with two pistons just above the mid point and two just below and rest the barrels on somethings so they don't rock about. Then ease the pair of pistons up into the barrels and then lower the barrels slightly and repeat for the other pair.

For ring compressors, find a length of PVC tube at the hardware store or a local construction site. Cut a 1-2" length and split them in two. Clamp the halves around the piston to compress the rings.

 

[hillsy]

It is by far easier to do this with another person - one on each side of the motor lowering the cylinder block down onto the centre 2 pistons, then down onto the outer ones. All the bikes I've done I have been able to compress the rings enough with my fingers to slide them in (the bore is chamfered at the base to allow this).

I did a KZ1300 like this with my brother (his bike) and it was really quite easy with the two of us.

 

[teazer]

It is by far easier to do this with another person - one on each side of the motor lowering the cylinder block down onto the centre 2 pistons, then down onto the outer ones. All the bikes I've done I have been able to compress the rings enough with my fingers to slide them in (the bore is chamfered at the base to allow this).

I did a KZ1300 like this with my brother (his bike) and it was really quite easy with the two of us.

Good answer Hillsy. I wouldn't let either of my brothers within a million miles of my motors - it would all end in tears. I tend to forget that not all families are as dysfunctional. :

 

[jay_kent]

Well Hillsy it look like your idea won. My brother and dad were up at my shop so I took advantage and had them help me. but I was biting my tongue while my dad was giving me shit for not getting the piston in the way he thought it should have. Hard to do that when he keeps lowering the head down sideways, but I digress.

So the lesson is it's best with 3 people. One to hold the block and 2 people to hold a set of piston rings each. We started with the cylinders 2 and 3 up, slid the head down, rotated the crank so pistons 1 and 4 met the head, held the rings while pushing down. all in all it took about 5 minutes, except for the 15 minutes of trying to bolt down the cam chain tensioner because it wasn't located right and the 20 minutes of finding the telescopic magnet to get the tension bolt out of the case because someone did something incorrectly.

Live and let live I guess.

Thanks for your suggestions guys.