Big end clearance specification

[Boot]

Anyone happen to know the total clearance spec for the big end bearing of a '91 200?

Looks like I'm finally going to be able to do my blown big end, if I can just find that spec.

Dying to ride!

Boot
Melbourne, Oz
85 Virago 1000
91 KDX200 (240SR)
http://www.copperleife.com/craig/bikes/kdx

 

[Dogz]

Con rod twist 0.03mm /100mm
Big end radial clearance 0.020-0.043mm up & down play
" " side clearance 0.4-0.5mm
Crankshaft runout under 0.03mm
Hope this helps. You also need a case splitting tool which I've never seen.

 

[Boot]

Fantastic, Dogz! Everything I could ever want.

I had a hell of a time getting the cases apart until I searched the forum and found a few tips on the process. I made my own case splitter tool with a piece of wood and a few bolts. I took some photos and will post them when I finish the film (no digital camera yet, sigh).

A friend swears I can line the crank halves up manually and whack them into alignment by eye. He used to do it all the time on racing two stroke engines, and found them perfect when he tried them in a lathe. I'm going to try.

Anyway, thank heaps for those specs.

Boot
Melbourne, Oz
85 Virago 1000
91 KDX200 (240SR)
http://www.copperleife.com/craig/bikes/kdx

 

[lankytim]

I'd be keen to see the pics of your homebrew crank case splitting tool. At the moment my score is: KDX200 crankcase = 1, lankytim = 0.

 

[andrew]

Con rod twist 0.03mm /100mm
Big end radial clearance 0.020-0.043mm up & down play
" " side clearance 0.4-0.5mm
Crankshaft runout under 0.03mm
Hope this helps. You also need a case splitting tool which I've never seen.

the side clearance is .40 - .50 mm standard, but it has a service limit of .70mm which is a fair bit more.
I was checking this only yesterday and mine is about .63, so it'll do for another year!

Cheers

 

[Boot]

Thanks for the updated spec Andrew.

Lankytim, I can't get those photos done yet, unfortunately, but it's a pretty simple concept. Just a big hunk of wood (very thick chipboard offcut in my case) with holes drilled in it and bolts.

An outer ring of bolt holes in the wood match the alternator cover bolt holes, and an inner one matches the crank shaft end. You buy six very long (100-120mm or so) 6mm bolts and bolt these through the wood into the alternator holes. Another suitable thicker bolt goes through the wood and through a nut on the inner side of the wood to push against the crank. Tighten it up and it works a treat.

I found that the crank was still stuck in the left case after using the above, so I drilled three more holes in the wood to match the left case and did the same thing.

If your main bearings are stuck on the crank, you can use a puller to get them off, or drift them off with a punch poked through the flywheel web holes (which I did). A friend holding a screwdriver and prising the bearing on the opposite side to the punch might help too.

I'll get all this online eventually. Let me know if you need more description, or search on splitting cases and you'll find heaps.

Good luck.

Boot
Melbourne, Oz
85 Virago 1000
91 KDX200 (240SR)
http://www.copperleife.com/craig/bikes/kdx

 

[lankytim]

Cheers for the tips, Boot!
I'm away from home at the moment so I've got bugger-all tools and workshop space and I'm trying to do a KDX big end & bearings rebuild in the middle of it all! It's a bit of a Swiss army knife MacGuyver job with some cheap crud tools as I've been able to muster. But it's all coming together OK now - although it's taken many weekends to do a day's work.
My service manual finally arrived a few days ago so now I'm a little more organised and knowledgable about the KDX. This weekend will be ripping suspension apart and re-greasing bearings. Just bought the KDX and I'm stoked with it, but it needs just a bit of TLC after the condition Old Mate left it in.
Did you get down to Phillip Island for the SBK the other weekend?

 

[Boot]

Don't you hate being away from your tools and workshop? Hope it goes well with the rebuild regardless.

No, I didn't get down to the SBK round at the island unfortunately, but I was there for the moto GP last year, which was wet but fun. It's a great place -- even if it does stick out into the wild weather of Bass Straight.

Cheers,

Boot
Melbourne, Oz
85 Virago 1000
91 KDX200 (240SR)
http://www.copperleife.com/craig/bikes/kdx