how many miles is a 550 good for??

I'm about to hit 50K miles on my zr550 and it's running better than ever. The bike is by no means babied - I thrash it for few hours every weekend riding the canyons, and thrash it some more every month or so at the track. But I am quite religious about maintenance. I wonder how long this engine can last. I've read posts saying problems start at 50K miles. Is it all about to fall apart?? Sure doesn't seem like it.

As long as you keep up on the maintenance should go an easy 100,000 miles. I got over 150,000 on my my kz650 top end. I only tore it apart for a performance piston kit. The bottom end is original. And I too run the snot out of it.

baldy110 wrote: As long as you keep up on the maintenance should go an easy 100,000 miles. I got over 150,000 on my my kz650 top end. I only tore it apart for a performance piston kit. The bottom end is original. And I too run the snot out of it.

Oh wow. That's incredible. And encouraging. The downside is that it delays an overbore I've been considering. Or maybe I just dig in anyway at some point like you did. Were you happy with the performance of the kit?

I went to the 810cc big bore kit with a lot of other mods. Yes very pleased with performance.

It is all abut how they are looked after, and how many cold starts as opposed to just the mileage number. I know a gpz550 approaching 90k miles just with a cam and primary chain plus service. Heard of a few 150k 550's.

The City of London used to run on kawi 550 and Honda CX500 - the despatch rider's favourite , they were everywhere. The GT550 shaft was the usual. They would run to about 100k and replace, as the whole chassis was pretty much worn out by then.
The frames used to rust really badly -crappy late 80's steel, the earlier bikes much more durable imo.

Clutch basket rattle and primary chain lash makes them (particularly the 550's) sound a bit clanky at high miles. Rattling camchains often due to a sticky 'auto' tensoiner. Oil leaks from block and head oil feeds common and an uprated oil jets are available as a later part number.

Good strong engines and great fun to ride -love that 6 speed close ratio box too.

Tyrell Corp wrote: I know a gpz550 approaching 90k miles just with a cam and primary chain plus service.

Doesn't the crankcase need to be split to replace the primary chain? At that point may as well do a complete overhaul, no?

Thinking more about this, and to correct myself -it was a Gpz550 forum Uk member I have met in person. It was a starter clutch replacement he did through the sump pan as opposed to cases split, starter clutch not the primary chain.

Only once heard of a primary chain failure, it was a race tuned bored out 550 running on 'top fuel' doing 90 rwhp which had a chain break. The later water cooled GPZ600 reliably shared a lot of the the same bottom end so these motors are very strong.

As well as primary chain slop there is clutch basket rattle and possibly deteroration in the primary shaft rubbers too all adding to the general clankiness' of an old 550 mill.

The last two I did had primary clutch probs so I split and replaced the primary chains too. The crank clearances were all within spec at about 50k miles. So not really routine maintenance and I suspect the hyvo chain would be one of the last components to fail even at high miles.

Tyrell Corp wrote:
a race tuned bored out 550 running on 'top fuel' doing 90 rwhp

Wait, what? Oh my god. You have to tell me more about that build (if you know more). What the hell did they do to that 550 to get that kind of power?? Most I've heard of is the MOMBA GPz 675cc(?) build, which did something like 70-80rhp, but it kept blowing through head gaskets so it wasn't reliable.

Ah, looked up "top fuel." That explains things somewhat.