650 Timing Chain

[Nessism]

I did the top end a while ago and installed new rings, and have imposed a 4000rpm limit for 800 miles (which is probably more than it will cover this summer anyway), so hopefully all will stay good.

J

Surprised to hear about the chain wear. Good job dealing with that. Would you please measure elongation per the service manual procedure and post the results here? I'd like to know if the manuals procedure accurately assess the wear present in the chain, or if there are other types of wear in the system.

As for your top end break in process, most folks around here subscribe to a more aggressive break in methodology. The rings need load in order to seat into the cylinder wall, and babying around during the break in defeats that purpose. Here is one such methodology that has gained wide acceptance...http://www.mototuneusa.com/break_in_secrets.htm Personally, I think that method is a little extreme, but the idea being to load the engine from the beginning and not go too easy is good. Aggressive riding using a city driving cycle works perfectly. Lots of engine load, no lugging. Vary the throttle position and rpm. After 50 miles or so of that get out on the highway and do some pulls to further load the engine. All this is well covered in the archives in older threads around here. You might want to do some more research (if it's not too late) to educate yourself.

Good luck

[G0FHM]

Hi Ed,

I'll dig the calipers out and measure the chain pin distance as per the factory manual, and report back. I didn't really do that initially, as my "gut" told me it was shot going by the noise it was making (especially it slapping on the top guide when pulling tight). I think the lateral movement proved that it was shot also - Obviously there was wear there for it to move so much!

I'm the same with timing belts on cars.... I change them at least 10k miles before the manual specifies!

As far as the "breaking in" goes, I've always been bought up to believe that it should be treated as gently as possible for a good few miles (a pal bought a brand new Ninja 636 a couple of months ago and Kwak specify 4k for 800 miles), keep the engine in the right gear for the rev range and don't labour it (ie no 20mph in 4th gear and whacking the gas tap open). I've seen (car) racers blow freshly rebuilt engines to the point of destruction as they've given them too much, too quickly as they have still been tight!

I'm even more paranoid with an air/oil cooled lump, as there is no temperature needle to keep an eye on!

I'll read the link you posted, and try and digest it!

Cheers,

J

[Nessism]

a pal bought a brand new Ninja 636 a couple of months ago and Kwak specify 4k for 800 miles

Cheers,

J

Can you imagine the liability if Kawasaki told everyone to use lots of throttle from mile 0 on their new bike? Wow! Yet, that's exactly what the engine needs. I worked for an OEM auto maker and each new engine is dyno tested before install. Basically, the engine is started and immediately the dyno applies heavy throttle and the rpm's are raced. The exact opposite of what the sticker on the gauges tell the new owner to do.

[G0FHM]

Hi Ed,

I may have screwed my pooch then, as the bike now has 24 miles on the clock! Plus time running freely in the garage whilst setting the carbs etc up.....

I'll take it out Monday for a bit of a workout, the weather is going to be too bad to do any heroics this weekend.

One thing that does disturb me in the "how to", is the fact he keeps going on about "modern engineering" giving a finer hone pattern etc. This engine is at least 32 years old, and has not been anywhere near a machine shop - The bores and pistons were within standard tolerance, but the rings were well worn (the end gaps were well outside specification, and they had lost their springiness), so it was a hone to knock the glaze off of the bores and new standard rings.

I have no pressure from the crankcase breather now, whereas before the rebuild a couple of seconds of the thumb over the breather trick gave major pressure in the crankcase and a loud whoosh when taking the tumb away! yes, I know.... I'm lucky to have not trashed any oil seals!

Right, I'm off to measure the old chain!

J

[G0FHM]

Ed,

FYI, the timing chain was 0.4mm over the "service limit" as specified in the manual, but the lateral movement was the most disturbing. Over a 6 inch portion of chain, there was nearly an inch of movement either way. Compared to the new chain which I checked on the stripdown blow!

I had to strip the top end down over the weekend, as it developed a serious smoking problem. It always did smoke a bit, which I put down to the new rings, but it was getting progressively worse, so I had no option but to strip it down and investigate, and pray that it was nothing serious.

Within 50 miles, the new valve stem seals that I fitted during the original rebuild had failed!

Normally, every VSS that I have removed in the past has been like pulling teeth - long nosed grips, tugging, twisting and lots of grunting, resulting in a trashed seal. When I fitted the new ones, they went on with a nice satisfying click. When I went to check them, I found that I could tease them off of the end of the guide with the end of a screwdriver, not via the bottom of the seal, but on the side!

The new seals were a much tighter fit, and to be doubly sure I put a smear of Silicon RTV around the end of the valve guide where the seal sits.

What was wrong with the original seals, I don't know. I can only assume that the originals were the wrong size that had been put in the gasket set. Putting the new ones on was a much harder job than the originals!

I whipped the block off, just to check the ring gaps etc and they were all fine. I suspected VSS's, as the smoke was at it's worse at idle and immediately on opening the gas after idle. Butterflies closed = High vacuum on the induction stroke, therefore sucking oil past the seal.....

Now we have a Katana that doesn't smoke

J

[1_v8_merc]

I can personally vouch for the "hard" break-in procedure used by manufacturers. I worked at a Harley plant, and watched them dyno-test the fresh bikes on occasion. They strap it down, and go full-throttle until 130mph or so, then let it come back down. There's a large over-head LCD screen with a speed indicator. This fairly typical of most companies...they only tell you to drive slow for liability reasons, standard legal crap to cover their ass.