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71' CB175 Front Suspension

haralej

Member
Joined
Jun 17, 2020
Total Posts
40
Total likes
0
Location
Minneapolis
My 71' CB175 has very sloppy feeling front suspension. It just doesn't have much dampening or stiffness at all.

I plan to pull off the forks & replace the oil & seals. Do you guys think this will help or should I look into getting new forks entirely (other posts on the old site mentioned getting forks from a heavier bike).

I'd ideally like to not have to replace the triple tree & just swap forks, but also the stuff I am seeing on ebay for a pair is like $100 bucks which seems like a lot.

I guess my question is:

Will replacing oil to heavier weight help significantly? I'm sure the oil in there is as old as the bike which is a 71' with 20k miles. Should I look at replacing the springs too? Or is it more worth it to just look at finding new forks.

Thanks!

Alex
 
When you say "new" forks, unless you actually find a set of NOS forks complete - not likely at all - then anything else you buy as a set is going to be used like yours. You can probably buy new springs somewhere, and replacing the seals is a good idea since you probably have no knowledge of how old they are and they start leaking with little notice after they're old. Heavier weight oil would help damping, but at this point if you haven't serviced them yet you don't know if there is any fluid in them at all. Sometimes fork seals start leaking and the POs let them go, and eventually they stop leaking when there's no fluid left in them to leak out
 
On the CB175, your fork upgrade options are limited with direct bolt-ons. The CB200T had the same length and track/trail as the CB175 but those are as difficult to find as the CB175 forks in good condition. You could search for newer CM185T forks that are also 31mm and the same as what you have, but easier to source second hand. They are longer, so they will stick out of the top triple tree further to get the same ride height. You will also need the CM185T triple tree as well, or an XL175 triple with adjustable clamps. There are also options to update to 33 or 35mm forks from larger Honda bikes, but that will take some work to adapt the triple trees to your frame. Few direct bolt ons that are easy, none that I would consider upgrades.

The fact is, all of these forks use almost identical technology that is 50 years old. You aren't going to be making massive changes, and you'll still need to be doing a rebuild on whatever you decide to adapt to the CB175 (seals, oil, etc). If the stock CB175 forks are clean and not bent or rusted out, just do a rebuild with fresh oil and new seals. You could potentially insert PVC spacers in the spring tube to increase spring preload if you are heavier or you could find a set of spring preload adjustable top caps on eBay to be able to adjust the front ride height externally.

There are internal modification and upgrades you can do (Race Tech gold emulators), though the costs can start escalating pretty quickly, too. For a street bike, take the fork off, clean and rebuilt it with new seals and a 15wt fork oil, and you'll be in a much better place with the front end of the bike.
 
Thanks guys,

I just ordered new seals. I'll start the project once they come in & I'll post here with any further questions or update as to how it is going.

Right now my plan is to pull em apart & check spring length & wear. If they are within spec or not super outside of it, I will replace with 15wt fork oil & new seals. If they are worn significantly, I may try using spacers to compensate.
 
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