Kz650 compression after rebuild

Thank you all for giving me advices

Unfortunately i found out where the problem was

Very bad seizure on exhaust camshaft. Probably some debris in the oil.

Now i am.seraching for the cause
Then i will try to clear up all oil passages
Then i will fit another head and cams

Finger crossed

vict182 wrote: Thank you all for giving me advices

Unfortunately i found out where the problem was

Very bad seizure on exhaust camshaft. Probably some debris in the oil.

Now i am.seraching for the cause
Then i will try to clear up all oil passages
Then i will fit another head and cams

Finger crossed

Bummer, :pinch:

Did you or your machine shop media blast the head? Reason I mention this is because there are some blind oil passages that grit can get inside and there is no easy way to clean it out after the fact. I blasted my 750 cylinder head using blast soda for this reason; I didn't want glass bead or sand down in the passages. Even at that it took a LOT of time to properly clean the head afterwards.

Well that sucks, Did it toast the cam journals?

Never mind - just read that last few posts. Yeah, that sucks! I've got maybe two or three cylinder heads that weren't cleaned properly after blasting - all the cam bearings are ruined in those...

[strike]How much static ignition advance do you have? Maybe try backing off the timing a bit. This is a common problem with too much static advance, combined with the increased displacement and higher compression ratio, plus a hot engine and starter motor.

The cylinders might be too tight (maybe!). Most of the machine shops I've dealt with agree that Wiseco's recommended piston to cylinder clearances seem to be on the tight side. Whenever I get a cylinder bored now, I go with 0.0015" - 0.002" clearance on single cylinder engines, 0.002" - 0.0025" with twins, fours and sixes. More if it is a racing engine.

in my experiences with 90% of the hopped up engines I've seen / had/ worked on... they are generally harder to start hot than when they were stock...all a part of the game.

My best friend's crazy big block and diesel - like compression '83 Honda CB1100F was by far the worst. He went through a pile of burned out starters and solenoids (some of them were mine, too!) until just giving up and resigning himself to not shutting it off until the ride was over! Or it was a long push home...[/strike]

It seems i am not the only one gone through this issue

Also the oil pump seems to be damaged (not as bad as cams and head journals but still damaged)
Good chance to fit a zr7 oil pump which seems to be a good upgrade

Well. lesson learned

Do you think i must split the cases again going through every mechanism and most of all the cranckshaft. Or it is safe enough to clear oil passages with a solvent and compressed air?

At present time i took off the head, cylinder block, oil pan, oil pump, and clutch.

I really would like to avoid splitting again the cases i just put together

These oil pumps do not have a reputation for failing. Mine has over 150,000 miles on it. I would suspect something was introduced into the oiling system. If it was my bike I would do a complete teardown. The rods and mains on these use plain bearings. These are not forgiving unlike roller bearings which are. I would tear it down and if there is a bunch of damage then I would be looking for a replacement engine and swap your big bore kit onto that one. If no damage then put it back together. You're only cost would be some Yamabond and time. Parts to repair these can add up very quickly, it' s usually cheaper to find a good engine. Good luck.

Do you know the source of the debris?

If the pump is damaged that's not a good sign. Think i'd pull down the engine, but then I'm a lunatic. Alternate is to purchase a good used engine.

I am in the process of taking again the engine apart. Searching for what happened in there.

By the way i am already thinking about what to do next. Prrobably i will find damaged crankshaft and bushings.

In that case if i buy new bushings and a good used crankshaft i will be ok am i right?

Just a few suggestions on what to do upon finding blast media, metal filings, swarf, or other abrasive contaminants in the engine's oil galleries. If you are re-using anything from the injured engine:
1. Take it apart completely. All the plugs, bearings, gears, collars, retainers, springs, bolts, washers, seals, etc. must be removed and cleaned, as more damaging material will invariably hide in or behind these items until you re-start your fresh engine and ruin it, too. Replace your oil pump - the old one is now junk!
2. This is a good time to do anything that requires drilling / tapping / cutting metal or using abrasives on any engine parts.
3. Clean all the parts several times (3 or more cycles) with hot soap and water. Solvent washing alone doesn't remove gritty abrasive things like sand blast media nearly as well as hot soap and water under high pressure. A pressure washer is good for this. Take the parts, and some clean plywood to rest the parts on while you wash them, to a local wand wash car wash if you don't have a good pressure washer at home. Make sure you blast through / out all the oil passages thoroughly, then bow dry with compressed air immediately to dry the parts and remove as much remaining dirt and debris as possible. Many car washes have a compressed air blow gun station - find one that does. Lightly oil any iron / steel / zinc parts to prevent corrosion. A spray of aerosol engine fogging oil works well.
4. Keep the parts clean and dry (but oiled lightly) until they are ready for assembly - wrap or cover in cloth to keep out dust and dirt. Use a cover that can breath - were I live, summer time humidity will start corrosion overnight if the parts are sealed in plastic bags. Ask me how I know this...
5. If the part has no internal oil passages, you can simply give it a solvent wash in clean (clear) solvent and blow it dry just prior to installation.
6. If a part has internal oil passages, just before you are ready to assemble that part in the engine, give it one last bath in hot soap and water (in a tub, followed by a thorough rinse in clean water is fine). While washing and rinsing, use bore brushes to scrub out the internal passages if you can, then blow dry it. Lastly, wash it in clean solvent and blow dry again.
7. When assembling your engine - follow the usual rules - keep your workspace clean and organized at all times, use only clean tools, put away tools and materials when they aren't being used, and wash your hands often. Don't re-use dirty shop towels.