Big Bore Kit

The Cruizinimage big bore kit comes with a head gasket to suit the larger bore size- how do you figure using the original 62mm gasket with 64 mm bore size ?
I just gave the machine shop the engine block with sleeves in their original place and all the piston/ring sets -they knew how to figure it out. When I got it all back, each new piston was numbered and therefore each bore was machined to suit each piston.
I see the seller has just started listing just the ring set for about $64. on ebay
If that had been available when I bought my big bore kit, I would have bought the extra set of rings just in case I break something during installation.

Like I said, I'm not sure of the usability of the standard Kawasaki head gasket when the barrels are going to be larger.

I do know, from personal experience, that the aftermarket ones do not seal the water jackets at all - I had coolant pouring out from one side of my head gasket! (this turned out to be a blessing in disguise as I discovered I had a bent valve when I took the head off to change the gasket).

I think the theory for using standard gasket is that the valve chambers in the cylinder head are still the same size as the gasket.

I see it that the larger bores will be trying to compress the metal grommets on the gasket (I have no idea what they are called - just checked - they are called "fire rings") around each chamber 1mm away from its edge - and I don't think this is going to be good enough and could lead to reduced compression and hot gasses destroying the mating surfaces over time.

I will probably use the gasket that came with the kit and try to add sealant around the water channels. The Australian, Gert, who takes these out to 1502cc uses a Three Bond sealant and I will look into this.

I am also planning to hand over the complete block and piston kits to the engineering company. I will also give them the Kawasaki specs for clearances on standard rings. If they can't work form this I will just find another company that knows what they are doing.

What do you guys use as a ring compressors?

I did mine by hand last time and managed to bend one of the lower oil scraper rings.

I wondered if I could make some out of coke tins (soda cans) with a large reusable tie-wrap (zip-tie)

The Kawasaki special tool doesn't appear to be available anymore. Others on the market look so large that they would not be suitable for installing our pistons.

Zed,

Have a look at my Top End Rebuild post............answers in there !

Pete F

Hi Pete,

Thanks for the reply. I looked through your post and can't find how you compressed the rings.

I've had the top end off a few times so (I think) know what I'm doing. I always try to do two pistons at a time just carefully persuading the rings in with my fingers.

I'm just looking for a better way to compress them without spending a fortune on special tools

Apologies mate, I was sure I put the tip in that post but it must be in another somehere.

I get the rings in the cylinder liners in exactly the same way you do (with fingers) & have one person each side of the block taking instructions on when to lower it slowly as the rings slip in.

I have also used cuttings from a fruit or veg can just a bit larger than the pistons (about 70mm) with a slit in them so they encapsulate the piston & rings, rather than expensive ring compressors, which dont leave enough room to get in anyway.

Best of luck with the job & interested to hear how yours completes, as just got my own started yesterday after many months work, and it FEELS GOOD !!!!!

Pete F
UK