Author Topic: Installing pistons (Read 4208 times)

cadler · « **on:** November 09, 2005, 10:16:42 AM »

i am getting ready to Install pistons into the Head after honing.
Any helpfull hints?

Also When installing the overhead cam how do I line everything up correctlly

Thanks
Craig

stevej · « **Reply #1 on:** November 09, 2005, 01:13:06 PM »

A tip I was given when I replaced the head & base gaskets on my 550 k3 was to line up all four pistons level with each other,then lower block gently a fraction at a time .Each time you stop just go along the pistons squeezing the relevant piston rings then lower a fraction more and so on it is time consuming but it worked for me.IM not a mechanic and there are proberably other ways to fit pistons in their bores but thats how I did it 15000 miles ago.Good luck.

Jonesy · « **Reply #2 on:** November 09, 2005, 01:13:45 PM »

What bike do you have?

lrutt · « **Reply #3 on:** November 09, 2005, 01:44:07 PM »

Quote from: stevej on November 09, 2005, 01:13:06 PM

A tip I was given when I replaced the head & base gaskets on my 550 k3 was to line up all four pistons level with each other,then lower block gently a fraction at a time .Each time you stop just go along the pistons squeezing the relevant piston rings then lower a fraction more and so on it is time consuming but it worked for me.IM not a mechanic and there are proberably other ways to fit pistons in their bores but thats how I did it 15000 miles ago.Good luck.

Basically what I've done on numerious occasions. I usually try and stabilize the rods and pistons with some rags stuffed in and around until I have all the rings fed in. You can setup it up so that 2 are slightly up on the other 2 if you wish. I've found that this did not necessarily help me any, but it may work for you. Plus the rags will keep any other potential crap from falling into the netherworld of your crankcase.

eldar · « **Reply #4 on:** November 09, 2005, 02:00:56 PM »

Now I dont know for sure about the sohc piston size but you can get a wrap around tool that you tighten up on the piston which squeezes the rings in, then you gently push or rap the piston with a rubber mallet. This will push the piston in and the rings should stay squeezed during transition from wrap to block.

DammitDan · « **Reply #5 on:** November 09, 2005, 02:25:51 PM »

I just rotated the engine so that 1 & 4 were at TDC and 2 & 3 were stabilized on the bottom and slowly worked the head down (after pulling the cam chain through the head and tying it to the frame above). Slightly rock the head back and forth, and squeeze in the rings with your fingernail as you move down.

Make sure you have your rings rotated to their correct positions BEFORE you start to put it back together!

As for the camshaft, on the CB650 you stand on the LEFT side of the bike (once again at 1.4 TDC) and insert the shaft through the chain so the index mark is on the RIGHT side of the bike. Then line up the index mark so that it's flush with the front top edge of the head, work the sprocket on the shaft, install the chain on the sprocket and play with the teeth until you get the sprocket/camshaft screw holes lined up with the index mark still flush with the top front edge of the head (everything should line up correctly if you've done it right). And DON'T attempt to use locktite on stripped out camshaft sprocket threads! Trust me on this one

Raul CB750K1 · « **Reply #6 on:** November 09, 2005, 04:34:58 PM »

I found the other day a big hardware store that had valve spring compressor. Just in case I asked wether they had piston ring compressor. They had, 6 euro each. Maybe I will use it only once in my life, but the trip to the hardware store for a clamp that I don't know wether it would do the trick made me buy the ring compressor.

What a heck, I'm spending almost the same money in tools that in parts. This CB350 twin is gonna be the most expensive piece of crap ever rebuilt!!!!

Raul

MRieck · « **Reply #7 on:** November 09, 2005, 06:38:18 PM »

Quote from: Raul CB750K1 on November 09, 2005, 04:34:58 PM

- This CB350 twin is gonna be the most expensive piece of crap ever rebuilt!!!!

Raul

Oh no Raul....I have the rebuilt most expensive "piece of crap" in the world. It wasn't actually rebuilt and it was never a piece of crap but it is old which makes it a piece of crap in some peoples eyes. A million dollars and counting.

DammitDan · « **Reply #8 on:** November 09, 2005, 07:32:06 PM »

We can rebuild it. We have the technology....

Bob Wessner · « **Reply #9 on:** November 10, 2005, 03:02:54 AM »

Hm, wonder what a bionic bike would look like.

cadler · « **Reply #10 on:** November 10, 2005, 04:32:26 AM »

Quote from: jonesdp on November 09, 2005, 01:13:45 PM

What bike do you have?

sorry.,It is a 1971 K1 that I got from the back of my brotherinlaws garage,It looked pretty bad but once I cleaned the dirt and surface rust it is not too bad. The pistons were froze in the cylinder and would not break free. I had to get a new block,pistons and rings and are ready to re assemble
Craig

Raul CB750K1 · « **Reply #11 on:** November 10, 2005, 06:42:41 AM »

I wouldn't say you need a new block. Once you free the piston rings (try soaking them in penetrating oil, probably a rebore is just as good as a replacement. Obviously, pistons and rings will have to go. Please somebody correct me if I'm wrong.

Raul

DammitDan · « **Reply #12 on:** November 10, 2005, 07:06:40 AM »

I think he's already done all that Raul...

bryanj · « **Reply #13 on:** November 10, 2005, 08:36:39 AM »

Raul what you say is right BUT at the moment its way cheaper to use a second hand block/pistons assembly. as to your ring clamp never needed one on a standard Honda but the overbore kits now that is different

cadler · « **Reply #14 on:** November 15, 2005, 06:01:38 AM »

Thanks all
What worked for me was to get #2&3 up first, I used 2 hose clamps to compress the new rings then tapped the cylinder down. The only problem I had was with the cam chain tensionerwas not in the proper position so had to do it twice.

eldar · « **Reply #15 on:** November 15, 2005, 08:04:51 AM »

Your hose clamp is the principle I was refering to. It works good as long as everything is lined up but you need to do that anyways. Hose clamp huh? As long as it worked and did not score anything, great!

Now just dont rod on it too hard during break-in! That would be my problem!

dusterdude · « **Reply #16 on:** November 15, 2005, 08:28:46 AM »

eldar,what you gonna run hard,i know you aint talking about your k8.

eldar · « **Reply #17 on:** November 15, 2005, 08:31:43 AM »

It would be impossible to run a K8 hard. It just keeps going even after it runs over the energizer rabbit!

dusterdude · « **Reply #18 on:** November 15, 2005, 09:07:07 AM »

yea the enegizer rabbit is faster

eldar · « **Reply #19 on:** November 15, 2005, 10:04:19 AM »

Yup. Faster to die!

dusterdude · « **Reply #20 on:** November 15, 2005, 10:40:13 AM »

you rabbit killer you.

eldar · « **Reply #21 on:** November 15, 2005, 11:16:26 AM »

At least I do it to a rabbit everyone hates! I also do not blow a hole through my door or drive into a river like a couple people I know!

dusterdude · « **Reply #22 on:** November 15, 2005, 01:26:05 PM »

uhhh,who would that be?

eldar · « **Reply #23 on:** November 15, 2005, 02:16:14 PM »

A friend of mine and his dad. They did this years apart, ; whole story is very funny

Terry in Australia · « **Reply #24 on:** November 17, 2005, 07:47:50 PM »

I've always used the "squeeze it in with your fingernails" trick, only because I never found a small enough ring compressor, and I don't like the hose clamp method, I tried it once, but wasn't impressed.

I put a small block of softwood under #2 and #3 piston, and lower the cylinder block unto them first, then carefully rotate the crank and do the two outer cylinders. I've never broken a ring like this, but if i could find a good small pair of ring compressors, I'd probably use them if they were simple to set up and remove once the pistons were in place. Cheers, Terry.

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Author Topic: Installing pistons (Read 4208 times)

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