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Offline Ridgeback

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motor work
« on: July 15, 2012, 06:20:15 PM »
Hi.  Can anyone point me to someone in the Brisbane (Aust) area who's good with CB750 K motors please.  I need someone to regrind  the crankshaft and re-bore the cylinders.   

I don't want to take it to just anyone.  I'm looking for the best.

Thanks.
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Offline HondaMan

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Re: motor work
« Reply #1 on: July 15, 2012, 10:32:44 PM »
Quote from: Ridgeback on July 15, 2012, 06:20:15 PM
Hi.  Can anyone point me to someone in the Brisbane (Aust) area who's good with CB750 K motors please.  I need someone to regrind  the crankshaft and re-bore the cylinders.   

I don't want to take it to just anyone.  I'm looking for the best.

Thanks.

You won't be able to "regrind" these crankshafts, as the bearings only come in -.0010" size. No one makes undersize bearings. What is wrong with the existing one? It takes a major event to damage them, and another used one is normally far cheaper than machine shop work.
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Offline Ridgeback

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Re: motor work
« Reply #2 on: July 16, 2012, 12:05:21 AM »
When I pulled the crankshaft I found 3 of the main bearings had worn through
the white metal of the bearing shells and the crankshaft is badly scored on
two journals. The big end bearing shells also show a lot of wear.
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Offline nancy

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Re: motor work
« Reply #3 on: July 16, 2012, 12:30:18 AM »
If the journals are BADLY scored - best to ditch it and buy another, newer and lower mileage/less abused crank. Just been down this path this month. My crank is OK..but might not have been. I found one here in NZ for $250NZ...should I have needed it...but I didn't... I spent $150 on having the crank and cases mic measured and checked by a machinist. End result - crank was still inside allowable tolerances...but a close call.
No way forward for a bad crank that I know of...except wave it goodbye. Probably indicative of years of hard motoring with few oil changes.
There are plenty around on fleabay...US$50-$70 and add US$140 or so shipping. Still some in NZ - should be plenty over the ditch - wouldn't there? What about asking Terry or one of your mates there?
regards
Mark
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Offline Retro Rocket

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Re: motor work
« Reply #4 on: July 16, 2012, 12:41:19 AM »
There are a few guys around Brisbane that can rebuild these old girls well, new crank shouldn't be too hard to find and will probably be a lot cheaper than trying to fix a scored one..... I may be able to help out with a crank... Where in Brisbane are you Ridgeback..?
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750 K2 1000cc
750 F1 970cc
750 Bitsa 900cc
If You can't fix it with a hammer, You've got an electrical problem.

Offline Ridgeback

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Re: motor work
« Reply #5 on: July 16, 2012, 01:30:41 AM »
I'm North of Brisbane, near Dayboro.
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Offline Retro Rocket

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Re: motor work
« Reply #6 on: July 16, 2012, 02:00:00 AM »
I'm on the southside, Redlands. I just bought a parts bike off a guy near Greenbank that said he had a spare crank, i can ask him when i pick the bike up later this week.... I know of an old guy thats is very good with machining , he is at Mount Gravatt, works from home...
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750 K2 1000cc
750 F1 970cc
750 Bitsa 900cc
If You can't fix it with a hammer, You've got an electrical problem.

Offline Ridgeback

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Re: motor work
« Reply #7 on: July 16, 2012, 02:51:32 AM »
I've heard of a guy at Wishart that works from home, but I wasn't sure he works on Jap bikes.  A mate of mine got some work done on his Trident there and say's he thinks he saw a Kwaka 900 motor there.  It wouldn't be him would it?  His name was Ron.

Either way, any further info would be good thanks.

Are the cranks in K engines interchangeable.  Mine's a K3.
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Offline lucky

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Re: motor work
« Reply #8 on: July 16, 2012, 04:11:47 PM »
Quote from: Ridgeback on July 16, 2012, 02:51:32 AM
I've heard of a guy at Wishart that works from home, but I wasn't sure he works on Jap bikes.  A mate of mine got some work done on his Trident there and say's he thinks he saw a Kwaka 900 motor there.  It wouldn't be him would it?  His name was Ron.

Either way, any further info would be good thanks.

Are the cranks in K engines interchangeable.  Mine's a K3.

Yes, the cranks are interchangeable.
Give them a visual check though.
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Offline CrankyOldGuy

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Re: motor work
« Reply #9 on: July 16, 2012, 06:05:05 PM »
Ever try Japanese Motorcycle Dismantlers in NZ.  I have e-mailed back and forth with them and they were quite helpful.

Harry O.
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Offline Retro Rocket

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Re: motor work
« Reply #10 on: July 17, 2012, 04:44:17 AM »
Quote from: Ridgeback on July 16, 2012, 02:51:32 AM
I've heard of a guy at Wishart that works from home, but I wasn't sure he works on Jap bikes.  A mate of mine got some work done on his Trident there and say's he thinks he saw a Kwaka 900 motor there.  It wouldn't be him would it?  His name was Ron.

Either way, any further info would be good thanks.

Are the cranks in K engines interchangeable.  Mine's a K3.

Ron Russ, is his name and i have his phone number here somewhere, he works on Honda's as well, i know a couple of guys that go to him, he's very fussy and does excellent work.  I'll get a price on the crank and get back to you...
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750 K2 1000cc
750 F1 970cc
750 Bitsa 900cc
If You can't fix it with a hammer, You've got an electrical problem.

Offline Retro Rocket

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Re: motor work
« Reply #11 on: July 17, 2012, 11:38:14 PM »
Ridgeback, I can get a crank if you want one, i have to go and pick some parts up in the next few days, if you want the crank let me know because i won't be going out there again any time soon.... Check your private messages, my phone number is there..

Mick
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750 K2 1000cc
750 F1 970cc
750 Bitsa 900cc
If You can't fix it with a hammer, You've got an electrical problem.
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