Bottom end inspection.

[utsman]

Hi Dirties,

Hey My Cr500 arrives next week. Soo excited. I don't know the condition of the engine yet. I know how to get a good idea about the state of the top end

Compression test
inspect piston and bore through intake and exhaust ports.

How can you assess the state of the crank and main bearings without stripping it down? Is there any tricks?

I know I can feel for play in the left main bearing by grabbing the flywheel and giving her a shake.
Any other clues

UTSMAN

[DJRacing]

There is no substitute for pulling the bottom end down. For piece of mind and reliability it is always best to pull the thing apart. And the carb as will and check the jetting. there is nothing worst than going to a meeting and hearing the big end colapse or it nip up because she was a bit lean or if she has been sitting around for a while and moisture has got on some bearing surfaces. A few hour pulling her down and checking everything can save alot of heart ache.

[Freakshow]

from my experiance, even when someone tells you have dont somthing, chances are unless they can hand you the parts they havent.  Ususally when you have a passing thought of selling something you always put back something in used , just because it should be OK. do what you can to check it, as a minimum -piss the barrel off and check the rod for side to side play, stick your ear in real close and turn it it shold be quite as a mouse, any grates, or bumpy feel in the slow turn, split the cases.
Also have a good look at the old piston and bore as it will tell you how well they have looked after it.

[utsman]

Thanks Guys,

I guess i'll just have to get it done. I am pretty mechanical and have done a few top ends in the day but have never split cases. I don't have time anyway - am working away a lot and only have time for family and riding not splitting engines. This is my dream bike and I  don't want any hiccups such as blown crank and cracked cases.
I live just near Serco in Brisbane. I might get them to do it. Anyone have experience with them? I'll ring them tomorrow for a quote.

LAter and thanks

[dirttracker]

a mate of mine has one one thing to watch for is the frame aint rusted out these things had a habit of it check the lower section of the frame, give it a tap and listen. the reason they rust is because the drain holes are in the wrong spot.

[Doc]

utsman, when you bought the bike or when it was advertised was it advertised or sold as a good running bike? If you paid good money chances are you got a good thing but if it was a bargain then I'd be a little iffy. Bought as a good runner I'd simply check all the fluids, airfilter and airfilter sealing then crank it up and ride it. If there is anything wrong you'll notice. There should be no fluid leaks whatsoever. If it was a cheapy I'd probably do much the same excepting with a little more attention to things like engine/exhaust mounts, brakes,check frame,check spokes and visually check everything else before attempting to start it. Cheack for case damage around the sprocket area and generally all over the cases. Drain the gearbox, look not only at the colour but also for metal filings in the oil. Nice clean oil in a crappy dirty bike to me says someone has been inside recently. Look at the fasteners, do they look like they been removed frequently, especially the inner crankcase screws and cylinder nuts, are they rounded or burred? Is there silastic anywhere to be seen? Or, you could probably ask someone more in the know with this model to have a ride and tell you what they think  to measure up tolerances will mean dissassembling everything.

[utsman]

Hey Doc,

Yeah it was sold as a good runner. The photos show a bike in very clean condition. I bought it from photos because of the Price. A 90's Cr500 for under 3K is hard to come by - especially in neat condition. Saying that I have never seen it run or even seen it. I bought it thinking that even if it needs a full rebuild it is worth it and it is to me. However I don't want to rebuild if not necessary and once you have the cases split, you may as well replace in my book.

The reason for the paranoya is I have heard of main bearings going and cracking cases. This is the bike I have wanted for the past 15 years and i am being over protective already - and it doesn't arrive till next week.

Knowing me I will ride it a couple of times then spend the dollars and get it sorted.

Cheers guys.

[zorroz]

Jap big ends seem to last forever. But crank bearing eventually give up. I split my 84 RM250 open for its 1st time in 23 years and the crank and gearbox bearings were all buggered, the big end was still tight.

[Doc]

yeah the bigends are pretty bulletproof on most jap stuff..this is why I'm a little critical of airfilters. Any I have ever had let go was because of crud injection via poor air filtration..a long time ago sounds like it will be a good thing utsman. I'd reckon you'll need to ride it to figure what you like and don't like before you go much further anyway 

[utsman]

Yep The Jury is in.

Ride ride Ride,

Can't believe work is sending me away for 2 weeks and I won't even be here when it arrives.

Torture.

Thanks Guys
LAter