Topic: Kawaski top end noise

[Dunk]

Any thoughts on this top end noise on an '88 Kawasaki EN450? Engine was always loud mechanically, quieted down significantly after a valve adjustment (most were twice or more spec), then this noise started after a cam chain adjustment. Changed the early style rotary cam chain adjuster for a new style ratcheting adjuster, no change in noise. Had to remove the exhaust cam oil tubes to adjust valves, pulled valve cover again and no change in valve adjustment. Replaced o-rings on these oil tubes, no change.

Could be coincidental timing, this engine suffered a total loss of oil pressure at one point, oil filter PO installed came loose while riding. Not sure how long it ran (a minute or two?), it's my buddy's first bike. Ran fine for nearly a year after that incident with no new or louder noises. Noise sounds like top end and much louder on right side. Gonna pull the valve cover again and if we don't find anything it's time to start tearing things down until the source is obvious.

Other fun is just replaced starter clutch. It failed as all three bolts were loose and one backed out, creating much metal shavings under the alternator cover, most seem to have been captured by the magnets. Oil did not come out metallic.

[desertrefugee]

Ouch.  That's ugly. Sure sounds like bottom end to me. Good luck.

[grcamna2]

Dunk,does it get louder when short-shifting under load while out for a ride ?

[Dunk]

It sounds relatively high pitched and louder towards the top of the engine. Granted I've never heard a rod knock on a bike engine, might not be as deep as a typical V8 with a rod knock. Doesn't mean it's not bottom end though. It is completely cyclic (not intermittent or variable),matches RPM, and sounds kind of slappy to me. I was thinking perhaps a wrist pin could sound more like top end noise.

Don't know about under load, have not rode it since this noise began after cam chain adjustment. Just a few brief times idling to observe any change. Don't want to cause more damage. Not sure how tightening cam chain slack could make this type of noise, chain does appear to have less slack when checking tension between cam sprockets.

[MRieck]

Ouch.  That's ugly. Sure sounds like bottom end to me. Good luck.

I agree

[MauiK3]

Sounds bottom end to me, ugh

[grcamna2]

Could the cam chain have jammed on one of the sliders after your last adjustment? doesn't sound that way..
What about the starter chain(if it has one);not from the left side ?

[Dunk]

Could the cam chain have jammed on one of the sliders after your last adjustment? doesn't sound that way..
What about the starter chain(if it has one);not from the left side ?

Doubtful, adjuster seems to go pretty far in and the engine turns smoothly. If it was jammed up or that slack I'd imagine it would be apparent after turning it over by hand let alone starting up.

Starter chain is pretty slack, but there is a tensioner which takes it up fairly tight. It can't rotate when the starter is not turning.

[Dunk]

I had a thought that the top end might not be getting oil. The top end is oiled via an external pipe that goes to each side of the head. I loosened the bolt on each side of the head and cranked it over, plenty of oil gushing out both sides.

[Dunk]

Bottom end noise... One rod bearing, what was left of it, had at least 1/8" clearance. The other looks terrible but hadn't spun yet. Only one main bearing looks real rough, main journals aren't bad. I suppose this crank could be saved with a polish on the mains, but at least the one rod would need cut and the rod resized. Probably not worth it compared to picking up a good used crank and rods.

[Stev-o]

Not familiar with this Kawasaki but there seems to be a fair amount of parts on eBay including a motor for $299....

https://www.ebay.com/itm/313535317407?hash=item490029459f:g:lM4AAOSwts5gpX-s

[desertrefugee]

Yeah, that's a mess. Like you, I'd probably not mess with machine work and try to source a decent reciprocating assembly.

[grcamna2]

Yeah, that's a mess. Like you, I'd probably not mess with machine work and try to source a decent reciprocating assembly.

+1  or get the parts from a known good engine.

[MauiK3]

Looks bad, lucky it didn’t just grenade.

[Dunk]

No real progress in the past week aside from sourcing a crank and rods. No markings that I can find on the case or the new crank, same as the old crank. According to the manual this seems to imply the main bearings should all be the same blue that were in it with the original crank. I'll get those and pastigauge, see how it works out.

An interesting bit about Kawasaki is most apparently have a mechanism that prevents them from being shifted into second if the bike is not moving. Three balls that ride in a groove between the shaft and gear. When the countershaft is spinning fast enough they sling outward and allow shifting into second. The trans isn't broken, it's a feature that prevents easily push starting the bike. Debating whether to leave the balls out so it shifts like a normal bike.

[grcamna2]

No real progress in the past week aside from sourcing a crank and rods. No markings that I can find on the case or the new crank, same as the old crank. According to the manual this seems to imply the main bearings should all be the same blue that were in it with the original crank. I'll get those and pastigauge, see how it works out.

An interesting bit about Kawasaki is most apparently have a mechanism that prevents them from being shifted into second if the bike is not moving. Three balls that ride in a groove between the shaft and gear. When the countershaft is spinning fast enough they sling outward and allow shifting into second. The trans isn't broken, it's a feature that prevents easily push starting the bike. Debating whether to leave the balls out so it shifts like a normal bike.

Glad this one's getting done-up correctly    I hadn't know about that feature on the 2nd gear push starting:I would leave them out if it was mine.

[Dunk]

This got done and he was fine commuting for a while, then we went to a pirate parade bike event last month and he dumped it trying to keep up with me on the way back on some twisty roads. Fixed and good since then but his wife isn't happy.

[grcamna2]

This got done and he was fine commuting for a while, then we went to a pirate parade bike event last month and he dumped it trying to keep up with me on the way back on some twisty roads. Fixed and good since then but his wife isn't happy.

Dunk,what was the extent of the labor that you did to the engine/transmission ?

[Dunk]

Good used crank and rods, new rod/main/countershaft bearings. New seals. Removed tranny balls. Lapped valves, new valve seals.

[grcamna2]

Good used crank and rods, new rod/main/countershaft bearings. New seals. Removed tranny balls. Lapped valves, new valve seals.

Do you feel it ran too long between oil changes,to damage the bearings like that ?

[Dunk]

Oil filter came loose on the highway and dumped all the oil. Spin on filter, PO had recently changed oil and looked brand new so we didn't change it when he got it. My friend kept riding a mile or so on the highway then a few minutes off the exit before stopping. Probably would have been fine if he stopped on the highway when he noticed it.