1994 Kawasaki Bayou 220 top end

[joelhofer]

Hi all, I have a 1994 Bayou 220 with low compression, how do I decide if I need a new top end or just rings?

[Mech]

First thing is to check the valve clearances are set right.

Then there are a couple of tests that point to worn rings. First is, when you do a compression test does the pressure come up to near the final pressure after only one or two compression strokes and then only increase slightly after that, or does the first compression stroke start out low and then every subsequent compression increase the gauge reading slightly to it gets to it's maximum. If it comes up compression by compression it points to rings being weak/worn. If the first reading is almost the same as the final reading it's probably valves

And the other test is to put about a teaspoon of engine oil down the spark-plug hole and then do the compression test. If the oil makes a big difference then it indicates worn/weak rings. Oil doesn't make much difference to leaking valves.

If you have compressed air, and can inject it into the spark-plug hole under a bit of pressure, while holding the crank at top, you can listen for air leaking out of the exhaust, inlet or crankcase breather/oil filler, and that will show where compression is leaking away.

You can't tell if you need a new piston and bore until the engine is apart generally.

[joelhofer]

Another question on this: can I put a different top end on this and use the same head? I mean a 250 or 300cc? Reason I’m asking is the 220 top ends I can find are pricey, even aftermarket whereas like the 300’s are cheap

[joelhofer]

I’ve got more questions just interested in peoples thoughts; when is it good enough to just hone the cylinder and put in new rings and how long does that last?

[Mech]

You won't be able to put a bigger barrel on that old head I don't think, and if you did it would probably not run good.

You pull the head off and then inspect the barrel and piston and then decide if the piston and/or barrel is too worn. If things are worn you get a ten thou bigger piston and get the barrel bored to suit the piston.

Jap bikes you can quite often though just put new rings on the old piston and they go for ages. If the piston and bore is worn, it's likely to need a crank job too.. maybe. Depending what the bikes worth and how many parts and outwork you have to get done it might not be worth overhauling the engine to that degree, but you can't tell till it's got the head and barrel off.

[joelhofer]

Thanks for the input Mech

[beast6228]

If you need a cylinder head, you can get used one with a 30 day warranty for under $200 with free shipping from Power sports nation (World's largest used ATV/UTV parts dealer), they also sell a completely rebuilt one for $400 (if you send them your old one, you get $50 back). As for cylinders, the Amazon/Ebay ones will work, but if your cylinder is in too poor of shaped to be honed you could always get your cylinder bored over for very little money, but then you would have to order a Wiseco piston that will fit the bore size. After reading the above, Mech basically said the same thing, but definitely check out Power Sports Nation if you need used parts.  

[Mech]

First you measure the bore to make sure ten thou oversize will take out all the wear, then you get the piston, then you take the piston and barrel to the shop to be bored for that piston. We don't just bore ten thou and hope it's good enough for a ten thou piston..

[SCmasterTech]

I had to get a new head for my 220 earlier this year. I was able to find a good used one on Ebay for a little over $100 shipped. 

[Gwbarm]

Thats good, i have found some good used parts on ebay lately also, there are sellers that sell quality parts, and there are sellers that sell junk, you really have to look at photos and read descriptions carefully.