?? about cost of rebuild

Over the winter I plan rebuilding my KZ650 engine. I'll be doing all the work myself except for any machine work that might need to be done.

Now before I ask my question. Let me state I fully understand no one can give me an exact figure. All I'm looking for is a ball park figure, or starting point if you will.

How much should I think about setting aside for the rebuild? Parts and machine work? Having never rebuilt a bike engine I have no idea what costs are involved.

The main reason I want to rebuild is that IIavo ia fsurehat nf shape it's in. It runs strong, has plenty of power, etc. But it also has some clunks and knocks, mainly at idle. If I tear it down and rebuild it I'll know exactly what I have.

Thanks for any guidance!

Bud1 wrote:

rebuild is that IIavo ia fsurehat nf shape it's in.
Thanks for any guidance!

Umm what is that line?

On topic, Ive heard gasket kits are around $100 but they turn up on EBay also. Theres one seller I wouldnt recommend getting any gaskets from though, I did and he sent it to me FOLDED in half. He did refund me but still. U2U me if you want to know who. (If he wouldnt have refunded me I wouldve bashed him on the forum)

Using original Kawasaki parts, I'd guess over $1000.00 including machine shop work.

For example: (all prices approximate)

Rings- $140
Pistons- $230
Main Bearings- $60
Rod Bearings- $60
Cam chain- ??
Valves- ??
Valve springs- ??
Cam chain tensioner and slippers- ??
Gasket set- $85

Bore block- $150-$180
Rebuild head- $100

Plus the various bearings, and odds and ends that always seem to nickle and dime you to death.

Be a lot cheaper to buy a used ZR7 motor and bolt it in

cost me less than 200 to do mine(from a 900 to a 1000)

block- free
pistons, rings- free
gasket kit- $90 local. +8 bucks for a gasket i bought before order the kit
honeing-$20
+ gas money from having to go get parts 2-3hrs away and to the local shops 30mins away

check out www.z1enterprises.com best prices iv seen so far

Hey Bud1.
I did a rebuild on a '77 650 last winter, punched it out to 700cc. Here's what I did. These costs are in Canadian $$$'s

$50 to bore each cylinder at the local machine shop. Triple angle valve job to clean up the seats, check springs, guides and set shims-$200 from same machine shop. Pistons/rings $100 from friend who had an extra set lying around (they should be about $400 brand new from Wiseco). Gasket kit $65 from dealer (A new factory head gasket might be tight on the fire ring so I went with a Wiseco head gasket to match the overbore.) I ported and lightly polished the heads myself at a local shop owned by a friend who donated his gigantic compressor and die grinder.

I didn't touch the rods except new wrist pins and circlips to hold pistons on the rods and they came with the Wiseco piston kit. I inspected but left the crank and bearings untouched as these motors are bullet proof from the factory on the bottom end. My motor only had 13000 miles on it and the cams, cam chain, adjusters and buckets were in very good shape. Carb rebuild kits for the 24 mm Mikuni's were $15 each. Rejetting...well that is an elusive art form that will take some playing around with but a healthy selection of main and pilot jets are pretty cheap and recommended if you go with the bigger bore and head work.

Total cash outlay - $650 ish....Coincidence???? Perhaps! Count on probably 9 bones and you should be safe...and if you really want to make your 650 get up and dance, drop 2 teeth on the front drive sprocket it will give you about 10% better acceleration but keep in mind that you will be sacrificing some top end and the bike will rev higher at highway speeds.

A word of advice...I would check the cam chain tension before embarking on the rebuild, you might find the new noise is simply a slapping chain as you said the bike doesn't seem to be down on power. Cheers-Colin

Totally rebuilt '77 650 Custom.
"Id rather laugh with the sinners than cry with the saints..."

DanOz7Five0 wrote

rebuild is that IIavo ia fsurehat nf shape it's in.

Thanks for any guidance!

Umm what is that line?

Well, truth be told that was me saying "I'm not really sure exactly what kind of shape it's in." :blink: :blink:

I got three hours sleep last night, spent nine and a half hours at work, came home, and posted my post. I remember nodding off while writing it. Guess I nodded off more than I thought!:blink:

Post edited by: Bud1, at: 2005/10/22 00:21

Steell wrote

Be a lot cheaper to buy a used ZR7 motor and bolt it in

I'll look into that. Might not only be cheaper but also easier!

Also remember the old adage,

"if it ain't broke, don't fix it"

Seems simpler to let it go till it quits, then deal with any trouble.

GL, mike

imyk wrote

"if it ain't broke, don't fix it"

Seems simpler to let it go till it quits, then deal with any trouble.

I've been thinking about that, too!:huh: I've driven cars/trucks with ticking valves for years and gotten by. But I'm not familiar with bikes yet and don't know how long I could push it without a)it breaking and causing more damage and b) leaving me stranded in the middle of nowhere. :huh:

This winter the bikes coming apart so I can fix and repair and mod some things and if an engine rebuild is in order that would be the time to do it, of course.

Course the more I think about it the more I think a ZR7 engine would look pretty good sitting in a freshly painted, modded 83' KZ650 frame!:blink: :woohoo:

Just think about how good it would look with a KZ1000 motor with a 1200 big block on it :evil: :evil:

There is no real good way of knowing what you will get into before taking the engine apart. I would do a leakdown test prior to pulling the engine apart and see if valves were holding seal. Once you have the head off, if they are sealing well, you will not really need to do a valve job but WILL need to look at the amount of wear in the valve guides and replace these, if worn. This is a machine shop job generally speaking. If this is done, they will need to clean up the seats because the valves will no longer fit exactly where they did prior.

Many times, the valves can be cleaned and the seats/valves can be lapped and all will be well with no real cost except for the new valve stem oil seals you will want to install. One determination of whether you need new valve seats is measuring the valve stems. If you need new seats, you would likely be best to find a new cylinder head because of the expense.

The next issue is piston rings. You will need to measure the piston diameter and cylinder bores. The difference is called clearance. The amount of clearance tells you if you need OVERSIZED pistons/rings which means not only pistons but cylinder boring (about $150 USD). If the clearance is within tolerances, a new set of rings and a $15 cylinder hone and you are in business. You will need gaskets and seals (appx $125 for both).

I would also turn the engine over and pull off the bottom case and check the transmission carefully. Replace anything; especially shift forks and such that are worn.

Usually, the crank and crank bearings don't need major attention... That leaves your low end clunks. These are most likely cam chain related. Get new or good condition used cam chain stuff as well as a new cam chain. This stuff is about as prone to be a problem as anything in your engine.

If you don't need a valve job or new pistons, you may get away with a few hundred bucks. Normally decisions are driven by what you find when you get into the engine. If you do a FULL rebuild, it can cost as much as $1000 as has been noted where you are replacing crank bearings and things like that.

Thanks for all the info! I think what I will do is set aside about $1500 (extra for just in case) for an engine rebuild. At the same time I'll keep my eyes open for a later model engine. If I happen to find an engine newer and not in need of a rebuild I'll go that route. Plus I could use the money set aside for it for other parts.

At least now I have a starting point.