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Discussion Starter · #1 ·
So I did a search of Ebay for CB 650 forks and it does look like the front end on my parts bike as someone mentioned in a previous thread. I was wondering about the air lines in the top caps. Does anyone know if those caps could be replaced with plain caps and how they would work without the air assist? Here is a pair like mine from Ebay.

www.ebay.com/itm/Honda-CB650-CB-650...263809?hash=item2157669e81:g:lG4AAOSwCXRcpQNE
 

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Discussion Starter · #2 ·
Still looking for an answer of weather I can replace the air assist top caps of the fork tubes with standard caps. My other thought is if I can't or if these forks need the air to function correctly maybe I could find another cap with the valve and use one on each side to get rid of the cross over line.
 

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Sensei
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Any caps with the correct size and threading will work.......
The added air pressure is a method of "boosting" the spring/damping as it presents the hydraulic fluid with more resistance to flowing past/through the valving upon compression but theoretically increases the return rate.....
Air caps with individual Schrader valve stems could be used, but the cross-over line keeps both sides balanced and of equal pressure pre-loading.....In the "worst case" (a blown fork seal on one leg), both forks would simply return to lower pre-load/normal spring suspension, damping at simply oil flow rate through orifice size....
 

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Discussion Starter · #4 ·
Thanks again Steve, I guess I have too much sit time on a rainy day and my mind is wandering. In the back of my mind I am still wondering if it might be usable on this 72 CL parts bike if I ever wanted to put it to use. I have been second guessing weather I could use the disc brake set up of the 650 of which I am pretty sure was from a 79 or 80 CB650 maybe a classic as later models are cast different and at some point put the axle on the front of the legs instead of the bottoms. I would probably have to use a 650 cast wheel and rotor and caliper. Perhaps I could sell the CL drum hub and wheel to get the wheel, rotor and caliper from a 650. Later
 

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Discussion Starter · #5 ·
So I was out looking at and measuring and noticed that the trees are 33mm 450 trees not 35mm 650 trees. The PO must have just opened them up enough to accept the 35mm tubes. One side of the lower tree is open more than the other side but I don't think to the extreme that it can't be used again on the correct 33mm 450 tubes. So I guess I will remove the 35mm legs and look to replace them with OEM.
 

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Discussion Starter · #7 · (Edited)
Ok thanks for clearing that up, I didn't want to pull up the rubber boots to measure and was measuring at the fork tube plug. I would have swore someone replied that they were 33mm. Do you know if 450 fork caps would fit the 650 or 750 fork tubes, both 35mm, or how I could find that out? I tried to look up the fork tubes on CMSNL and neither the 650 or 750 dohc bikes, which is what I think these are from, have the air assist caps. The caps of the 450 are not the same as the others. Keep looking I guess
 

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Ok thanks for clearing that up, I didn't want to pull up the rubber boots to measure and was measuring at the fork tube plug. I would have swore someone replied that they were 33mm. Do you know if 450 fork caps would fit the 650 or 750 fork tubes, both 35mm, or how I could find that out?
Can't answer that - Steve might know.
 

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You should check the CB650 owners manual about the air pressures. Honda designed the front shocks for a given bile weight. My 81 GL1100 has air assisted front shocks and air is required. The range is 14 to 21 psi. It will bottom out if it is low. My 85 GL1200I the shock air is 0-6 psi. It all depends on the spring rate. The 650 is heavier than a CL450 so the pressures may need to be lower. I don't know about the CB650, but in 1980 the GL got Teflon bushing in the shock sliders and it was a huge improvement. One of my buddies traded his '77 wing in for a 81 just to get the forks. This might be a good upgrade.
 

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Discussion Starter · #10 ·
Jim I am not 100% sure what they are off of, the Ebay link above look the closest to them I have found. It says they are from an 82 CB650 and I have also seen a set from a 78 CB750 classic that look the same. I have decided I will not use them and will replace with original. The only reason I need to know what they are is I don't want to misrepresent what they are when I try to sell them. Thanks all for the info.
 
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