520 Chain Conversions for CB350 CL360 CB400 CB450 CB77

I did some fast and furious research and found that many sellers of steel sprockets claim they are Case Hardened and it seems to be a common term that misused by many people. Although the term is in common usage, it's still not appropriate. Sprockets are either flame hardened or induction hardened and I could see why you and others could be confused. After all, lots of people use the term.

I guess it's like the term Cafe Racers which no longer has anything to do with racer and more to do with a Starbucks parking lot. People use the term anyway to indicate that the sprocket has been hardened.

Never had a chain break? We managed to break race chains on our Aprillia RS250 cup bikes. I'm still not sure why, but it happens. On the street, people spend very little time above mid revs or 50% throttle and for sure a CB twin or old SOHC will not work any modern chain very hard.

Our CB72 racers ran 520 chains back in the day and that meant having sprockets machined. Next one I build, I'll come and see what you have available to save a whole truck load of time and cost.
 
The tensile strength, for the small twins, is almost irrelevant. The advantage in the o-ring chain is longevity. No one with a small twin is going to exceed the tensile strength of the chain. However, plain roller chains wear out much faster then o-ring chains. the non o-ring chains elongate faster too, due too dirt getting into the roller/pin interface. chains that break are nearly always worn out pins, due to lack of lubrication or failed lubrication. I don't think any 30 year motorcycle would ever approach the yield strength of a modern chain.

I have no doubt a 520 o-ring/x ring chain will last far longer then a 530 non o-ring chain.

Now if you are turbo-charging a Hayabusa, then tensile strength is the important issue. For most bikes, the chain life is more important then the number on tensile strength. All the name brand 0-ring chains are way past any tensile strength needs of most of the bikes here.

So a 520 chain fits without rubbing, has more then enough strength, and will actually last longer then a 530 non-ring chain.

A 530 )-ring chain, because of the width, will likely rub and may cause damage to the cases.
 
The CBR600f1 was 87-90. I went down 2" in height going to these 17" wheels from the 18" stockers so I have to figure how much bigger I have to go on the back to make up for it. I see you finally let it slip who the manufacturers was and I have found Driven Racing to be the least expensive so far.
 
o1marc said:
The CBR600f1 was 87-90. I went down 2" in height going to these 17" wheels from the 18" stockers so I have to figure how much bigger I have to go on the back to make up for it. I see you finally let it slip who the manufacturers was and I have found Driven Racing to be the least expensive so far.
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We only use Driven for the modern sportbike. They dont really make anything for bikes prior to 1987. We do a ton of business with Noam over at Driven with the 520 kits. We can get a rear sprocket no problem from them and can beat any prive with them. The front will come from rebel as they are the only one who make front for the vintage bikes.
 
o1marc said:
The CBR600f1 was 87-90. I went down 2" in height going to these 17" wheels from the 18" stock
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No, you lose 1/2" either side so 1/2" lower.
Smaller wheels will lower gearing so you need smaller rear sprocket to get back to 'stock' gearing
 
crazypj said:
No, you lose 1/2" either side so 1/2" lower.
Smaller wheels will lower gearing so you need smaller rear sprocket to get back to 'stock' gearing
Click to expand...
I meant 2" of overall height.
crazypj, is that you're final answer or would you like to call a friend?
 
Check the overall diameter of wheels, if they are smaller than the originals you will have lower gearing.
You can also mark tyre and roll it along the ground, smaller circumference doesn't go as far for each revolution
150/70x17 is probably close to a 3.75x18 tyre but the drag on wider tyre is much higher so you may need lower gearing
 
I lost an inch in wheel diameter and an inch in tire diameter from going to a 120-70-17 from a 4.00-18, so that totals 1" lower in ground clearance.
For numbers sake lets say I am running a gear ratio of 2/1 with a 36" circumference tire. For every revolution of the motor the wheel will turn 1/2 a revolution or 18". When I switch to the smaller tire which is only 30" circumference each revolution of the motor will turn the wheel 1/2 revolution and only go 15". To go the same distance as the 36" tire I would have to spin the motor more to go the same distance. By putting a bigger sprocket on the wheel I can now go further per each revolution of the wheel and get back to the 36" distance with the same RPM.
Am I wrong?
I don't see how drag enters into the equation.
 
Yep, your wrong. You need a smaller sprocket on the back or a bigger one on the front (or both)
If front sprocket has 16t then rear 48 you have a 3:1 ratio. If you use 56 rear, front sprocket has to turn further to pull wheel round same number of revolutions as you now have a 3.5:1 ratio
A wider tyre has more grip because there is more rubber on the road, the extra rubber heats up through friction.
Friction = drag
 
I brainstormed some more and you are correct. If I went from a 2/1 (r/f) ratio the rear would turn one half a revolution for each revolution of the front sprocket. If I went down in size on the rear to a 1/1 ratio for ever turn of the drive sprocket the rear would turn one full revolution also. There's that damn dyslexia kicking in again.
Now, since you're so educated on this subject, if I change only the rear sprocket with a 2" smaller diameter wheel/tire, how many teeth smaller should I go on the rear to bring the speedo back in line?
 
Have you measured the actual wheel sizes for overall diameter?
You need to do both, even if it means getting someone to measure 'stock wheel tyre combination, sizes are probably closer than 1"~2"
I like to run slightly higher gearing on my bikes as I don't mind revving them and don't do wheelies
If your right on size you'll probably need 30t~32 rear and 17~18 front (I think stock is 16 or 17/34?)
 
crazypj said:
Have you measured the actual wheel sizes for overall diameter?
You need to do both, even if it means getting someone to measure 'stock wheel tyre combination, sizes are probably closer than 1"~2"
I like to run slightly higher gearing on my bikes as I don't mind revving them and don't do wheelies
If your right on size you'll probably need 30t~32 rear and 17~18 front (I think stock is 16 or 17/34?)
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Yes, I wasn't taking those numbers off the top of my head eyeballing it. I was a race car driver for 20 years, I know the importance of tire sizing. Gearing on this bike was 17/38.
Here is a stock mounted CB400f 4.00-18, it is 25.25" and has a 80.25" circumference:


Here is the CBR600f1 with a 120-70-17, it is 23.375" and has a 74.24" circ.:



side by side:


I am having trouble locating a 120-70-17 rear tire so I will probably go to a 130-90-17 for final set up.
 
Wow, about 6" less circumference, that's a lot
stock does around 790 rpm/mile
CBR600 about 855 rpm/mile
34 t rear should be OK (stock on 360 so real easy to get hold of)
I would probably use 17/33
 
Do you think with a 130-90 I might want to go to a 34t, I'll definitely be gaining some height with that tire?
 
I would probably still run 33 t rear, cheap enough to fit a 16t front if you need it
 
If I order the sprockets its comes out to 149.99.. Free shipping is at $150. Do I really have to get something else or do yall let a penny go? I mean you can charge me the extra penny. I looked and I don't need anything else right now. I would get some valve stem caps or a shirt but I didnt see either...
 
I ended up finding some rim strips.. I needed some so i got them, it was still cheaper than the shipping. Plus I got it in one place and they were pretty inexpensive. So thanks haha! I was getting a 40t rear and 17t front for my 400F. I ordered it a couple of hours ago. Won't see the package for another 24 days...:/
 
ronnie said:
I ended up finding some rim strips.. I needed some so i got them, it was still cheaper than the shipping. Plus I got it in one place and they were pretty inexpensive. So thanks haha! I was getting a 40t rear and 17t front for my 400F. I ordered it a couple of hours ago. Won't see the package for another 24 days...:/
Click to expand...

Got it going out tomorrow.
 
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