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Compatible forks

hdnjn

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Hey guys. I need to buy a used replacement fork for my 1981 CB750F.

My question is: which years/models have the exact same fork as my bike?

How about CB750K, CB950, or perhaps later models than mine? This information would help me a lot while looking for a replacement fork. Thx a lot.

 
'81F uses 37 mm. fork and not many others, the lengths change or the offset on the triples changes too. Bottom of fork is different for different axles. '81 and '82F will use same fork though in same model. Nighthawk uses 37 but different at the bottom and the triples are not neutral, angled. Thinking one custom may use 37 too but not sure, bottom again will be different. K, L, (early C?) use 35 mm. 900 and larger use 39 mm. Honda changes something on almost every fork. The widths change between tubes (longer axles needed) or the brakes change to match antidive units yes or no.

The only exact fork is F '81-'82. '80 F is 35 mm., same as K.

It's a mess.
 
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It sounds worse than I originally thought! Thanks for the info. I can find pretty much every year fork except 81, 82f. I found a chart on Honda models and fork size by year and the 80- 82 cb900c uses the 37mm fork. But, will they work? From the sounds of it probably not.
 
AMC49, I did some research and discovered that the 80- 82 cb900c use the 37mm forks and the uppers and lowers are Identical. Besides length, what else would differ? Seems like they are the same fork.
 
The lowers are NOT the same, C lowers mount a leading axle where the F uses a centered axle. There can be anti-dive or not issues in there too, meaning the caliper brackets are different, they bolt on in different ways. One fork at least in there has only ONE anti-dive unit where if it is present they usually get two. All forks spread about .300" wider '81 and later too, the axles are longer and triples spread the holes to suit.

37 mm. C forks will go on the bike but the leading axle slows down handling. The axle must change going to them too. Fender holes will be close but maybe not exact.
 
Thanks for the explanation. I will keep hunting for ''81 or '82 forks then. Wish me luck!
 
I used a set of '78 GL1000 forks on my '79 CB750F build. Used GL1000 triples, axle and headlight ears, jury-rigged gauge mount and the brake calipers swapped right over.
 
I forgot about that one, the later big motor DOHC factory race bikes used 39 mm. forks off GL, the earlier ones had 35.
 
'81F uses 37 mm. fork and not many others, the lengths change or the offset on the triples changes too. Bottom of fork is different for different axles. '81 and '82F will use same fork though in same model. Nighthawk uses 37 but different at the bottom and the triples are not neutral, angled. Thinking one custom may use 37 too but not sure, bottom again will be different. K, L, (early C?) use 35 mm. 900 and larger use 39 mm. Honda changes something on almost every fork. The widths change between tubes (longer axles needed) or the brakes change to match antidive units yes or no.

The only exact fork is F '81-'82. '80 F is 35 mm., same as K.

It's a mess.


I have a 1979 Cb750 Limited with a front end swap that came with it that's unfinished. I'm wanting to go back to the old because I have no idea how to do a complicated fork swap. Is it possible to buy the front end from a regular 1979 Cb750k and use that?
 
if you are only looking for new forks because of the condition of the chrome, there are a few companies out there that will repair and re-chrome your existing fork tubes, and there are a few other companies that sell aftermarket replacements.
 
if you are only looking for new forks because of the condition of the chrome, there are a few companies out there that will repair and re-chrome your existing fork tubes, and there are a few other companies that sell aftermarket replacements.

I'm looking for a whole compatible front end essentially but I also want to keep the original rims somehow. This bike has the front end of a 1994 FZR1000 (I think) right now but the previous owner was halfway done with the conversion and I have no idea what I'm doing when it comes to conversions like this. The steering stem is rusting a bit but I'm not even sure if I have all the parts for it and if it's the right size for this conversion. Not only that but I have a mystery axle with mystery spacers that don't work properly. The wheel the misaligned because of this.
 

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Ah, gotcha. go on www.ronayers.com and use their part diagrams to check out what you need. some of the parts can still be purchased brand new through honda dealers (such as ron ayers). you can also sometimes search the part numbers and it will tell you if it was used on other years or other models. the other parts you can't buy new, you might be best searching through ebay. you may have to settle for something in less than good condition and recondition them. TNK makes fork tubes brand new from Italy and are a reasonable price.
 
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