Re: Scott's 1974 CB360 project- She is alive!!

crazypj

Split personality, I fake being smart
Nice. Probably lighter than original 33mm tubes as well, lot more was done on computers when VTR was made so uses thin-wall tubes, probably 3mm instead of 3/16"and more precise castings for sliders.
 

SpottheDogg

Member
crazypj said:
Nice. Probably lighter than original 33mm tubes as well, lot more was done on computers when VTR was made so uses thin-wall tubes, probably 3mm instead of 3/16"and more precise castings for sliders.
CrazyPJ, you probably know some specs on the CB360 steerer. When I put the CB-1 front end on my VTR250 I had to use the VTR steer tube, aparently the CB-1 had a very common Honda steerer where the VTR had an uncommon one. I still have the CB-1 steer tube and I’m hoping maybe I can just press that into my VTR250 triple if it’s correct for the CB360. I can always remove the tube from my CB lower, but it would be nice to have a complete 360 front end. Maybe I can sell it
 

SpottheDogg

Member
Ok, updates for anyone wanting to do this swap:
1. you’ll need to space the caliper in, two spacers id, 8mm, od 18mm, L 7mm and get two M8x1.25 40mm long bolts.
2. you need to ovalize two of the six rotor bolt holes slightly to get the stock long bolts through. Then you’ll want to drill four new holes based on the 6 bolt rotor pattern, tap them 8x1.25 and buy four bolts 15-20mm long.
3. you’ll need two new axle spacers (this does not accommodate speedo drive) id 15mm, od 22mm, Length for right side 25mm, length for left side 21mm. You need to remove the VTR250 speedometer drive stop on the fork leg (or at least shorten it a couple mm).
4. You will need a steer tube donor.
 

crazypj

Split personality, I fake being smart
SpottheDogg said:
CrazyPJ, you probably know some specs on the CB360 steerer. When I put the CB-1 front end on my VTR250 I had to use the VTR steer tube, aparently the CB-1 had a very common Honda steerer where the VTR had an uncommon one. I still have the CB-1 steer tube and I’m hoping maybe I can just press that into my VTR250 triple if it’s correct for the CB360. I can always remove the tube from my CB lower, but it would be nice to have a complete 360 front end. Maybe I can sell it
For alloy bottom yoke you need around 0.003"~0.004" interference fit for a press in stem. If it's forged steel, you can be a little looser but will need to weld it in. Are all steerer tubes steel? Swapping to 'standard Honda' bearing sizes is a real good idea
 

SpottheDogg

Member
I checked it out today, the CB uses the alternate length tube so I ground the weld off and pressed in the spare steer tube I had in my bin. Will have it welded in this week. Looks like I can probably use my CB360 fender with a little creativity. :)
 

crazypj

Split personality, I fake being smart
I heard cranks fail big time on the Hawk if you go over 80bhp? The offset crankpin shears although I couldn't find out if it was torque or rpm causing it?
 

SpottheDogg

Member
I finished the steer tube swap and slid it all together, one thing I hadn’t measured was the fork length. The VTR250 forks are about 4.5” longer so they will be sticking above the upper clamp over 3”. I don’t mind, but some may. I will use clip-ons mounted above the upper triple to reduce the odd factor.
 

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SpottheDogg

Member
Well, I expected it to be pretty easy and it was. :) One thing I forgot to mention this morning was that neither the VTR250 or CB360 steertube seems like it will work. I used one from a CB-1, which is the same as a lot of Honda bikes. I just happened to have one since I put a CB-1 front end on my VTR250.
 
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