Katit's 1978 KZ650 project

katit wrote: Oh well. OK. This is what I wanted so I got it

Side question - what size glass bead media to use in sandblast cabinet for engine casings? And where do you get them?

I used 80 grit glass bead in my blast cabinet. I got it at a Harbor Freight, but I am not sure where you are located.

Can't make up my mind. Start with complete resto or keep pushing in getting it running.

If I get engine off, rebuild (whatever it takes) and put it back in - it will be easier/quicker and I will get to hear/run it before another disassembly.

Starting with frame will just take much longer. It will be done anyways but starting with engine, getting it run properly and then doing frame resto makes some sense too

My .02 is get it ready for spring. No sense in it being down any longer than necessary. Do more next winter if wanted/needed. YMMV

slayer61 wrote: My .02 is get it ready for spring. No sense in it being down any longer than necessary. Do more next winter if wanted/needed. YMMV

Idea was to get it completely restored anyway. I have other bike to ride. But want to see some result sooner (i.e. running engine) hence dilemma. There is plenty of other stuff to work on, if I want to make it ride-able to my standards - will have to overhaul many other parts. Brakes need to be done, forks just to name a few..

Finally got time to do some more work. Well, first of all head has to come off anyway. If head comes off- cyliners have to come off as well, gasket need to be changed anyway. With so much dirt I feel like engine need to come apart as well. Or maybe not. But if I don't do everything (check whole engine) - I might be wasting gaskets and time.

So, with head it's clear - need to be replaced (will see what other spare engine head look like). The one from a bike has most of the cam lobe bolts stripped and one lobe (# incorrect.

Question about cylinders. See pic. Seems like bike was parked for awhile and pistons stuck and corroded to cylinder walls. No scratches. But no hone marks either. Cylinders wear like a mirror. I can't feel anything with a nail when checking those spots.

Course of action?

A. Measure pistons and cylinders. If all in spec - clean up, replace rings, hone cylinders and go.
B. Buy +0.25-0.5 piston kit. However, not sure how good those $200 "reproduction" piston kits are.

If its got a rust ring from sitting you really need to re-bore. You might get away with a hone and new rings for a while but i would bet you will be revisiting this issue in a short amount of time.

DoctoRot wrote: If its got a rust ring from sitting you really need to re-bore. You might get away with a hone and new rings for a while but i would bet you will be revisiting this issue in a short amount of time.

What is my options to make it right then? Looks like NOS pistons sold by each, hard to get "kit" and then rings, etc - get's expensive and hard to collect.
2nd choice is reproduction pistons at ~$300 - set with rings IMDPistons from UK
3rd choice - Wiseco +2mm kit ~$600. This one looks interesting. Is there enough in stock sleves to go +2mm. Is it good idea? Adjustments to carbs/other needed? I am not really interested in more power, but I want reliable quality parts
4th choice - cruzinimage - most affordable, $150 for kit?

The Wiseco pistons are probably the most popular option on this forum. I don't have experience with IMD, and limited experience with Cruzinimage, just used their rings with mixed results. Maybe some other member can chime in here on IMD becuse they look like a good inexpensive option. Don't forget to budget $60-80 per cylinder for bore and hone.

Another option would be to get a good used block and fit some new rings

If your pistons are in good condition you could have your block resleeved and bored for them - that may be the least expensive.

ghostdive wrote: If your pistons are in good condition you could have your block resleeved and bored for them - that may be the least expensive.

Hm. Thats an option too. But still need rings. Pistons look good. I have another locked up spare engine which might be even better.
The only problem - work quality. Complexity of work (resleeving) goes up, cost goes up. Potential for error goes up.

I searched for cruzinimage here on site and people give them good reviews. I also searched online and found good reviews. For $150/set I can't see how it will be any cheaper to resleeve.

Wiseco at $550 for +2mm looks like a quality option. But question stands. Will +2 mm throw tuning out? Will it require rejetting?

Any suggestions for good shop to do cylinder work?

I want it to be done right. But at the end let's be realistic. I won't put 10k miles on a bike in my life. No need to build it to last forever.

Shipping a block is expensive so that will factor in to the price. APE does boring and honing at a discount if you buy the piston kit through them - they sell the wiseco kit. The bigger bore and higher compression of the Wiseco pistons will require rejetting. I think they are drop in other than that, but i would double check. I use LA sleeve for my machine work as they are down the street from me and do great work at a reasonable price.

The cruzin image pistons are excellent value for money, I'm fussy as hell and are buying them for my GPZ750/810, i'll be running higher compression and bigger cams and am not worried about them one little bit. My friend is a mechanical engineer/mechanic and he's used them on everything form Kawasaki's to CBX1000, to CB750 honda's with absolutely no problems, and this guy gets 130 RWHP from a methanol slurping cb750 engine, so I'm quite happy to accept his opinion. I was told that the IMD pistons are the same piston, just with a top heat coating, I was also told the pistons {both IMD and Cruzin image} come out of Korea not China but I don't know this for sure...