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Discussion Starter #1
Hi folks
Has anyone tried to install a cb450 crank in a cb350 bottom end?I am in the process now I have the crank with the correct bearings and crankshaft works is going to install bushings in the small end of the rods to except 15mm wrist pins plus lighten and balance the crank.
This is a learning curve for me just wondered if anyone has done it before and knows of any problems.
Also JE Pistons is making some 73.5 mm pistons like the old Powroll pistons sleeves are coming from LA Sleeve.
Using a Mega Cycle x 125 cam 1mm larger valves and beehive springs 34 mm flat slides.
Any ideas?
 

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The 450 rod center to center looks about a 1/4" wider. Jugs appear to have enough material to work. The 450 primary gear spline and thread for the oil spinner cup is about 1/2" longer and I'd think would could be machined to work. I've heard of cb77s being done to 500s across the pond for race eligibility I think. How big intake valves could the 350 fit? Sounds interesting!
 

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Discussion Starter #4
I have the primary gear for the 450 crank,but I will not be using the oil slinger I'm going to use an external filter and oil cooler.
I will drill and tap the clutch cover at the oil passages i've done this on other engines and it worked well.this will fix the clearance problem.
I will be using a sleeve from LA Sleeve made to my spec.
On valves I think you can go 2mm over but I'm using 1 mm over as it worked well on my Bonneville LSR bike and left plenty of meat at the seats.
Will try to send pix soon.
Terry
 

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Anyone with an update on this?
 

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I wonder the reasoning for doing this. Why not just put the 450 crankshaft into a 450 engine, and spend your money on pistons, valves, porting, and cams?
TOOLS
 

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I just gotta ask.......WHY?? seriously, short of just making work for yourself for the sake of something to do, what are the potential gains of going with a 450 crank? is the stroke different? more power/torque? There has to be some reason for doing this amount of work....I'm genuinely curious!

I mean, I have done crank swaps in V8 and inlines (383 stroker, 4.7l stroker inline in a Jeep) but usually there is a performance goal in mind.
 

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I know, right? But since Mr. Dreadnaught started it, I was wondering where it has gone.
 
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