Topic: CB750 K1 fork dust seals

[henrikm]

Hi guys,
I'm starting the process of collecting parts for my 1971 750 build. I'm a total newbie when it comes to motorcycles (this is my first one!) so you're probably going to pull your hair out of my endless stupid questions.

That said I want to remove my front fork gaiters, as I like the look without better, and have understood I need dust seals. I found some on ebay, will these work?

I also read somewhere that the earlier K's had "untreated" forks. Do I need to treat them with anything to avoid corrosion?

And yes, I'm going to change the fork seals and do a total rebuild of the front end.

Thank you!

[MCRider]

Hi guys,
I'm starting the process of collecting parts for my 1971 750 build. I'm a total newbie when it comes to motorcycles (this is my first one!) so you're probably going to pull your hair out of my endless stupid questions.

That said I want to remove my front fork gaiters, as I like the look without better, and have understood I need dust seals. I found some on ebay, will these work?

I also read somewhere that the earlier K's had "untreated" forks. Do I need to treat them with anything to avoid corrosion?

And yes, I'm going to change the fork seals and do a total rebuild of the front end.

Thank you!

On your K1 what you'll likely find is that the fork tube is not chromed all the way up. When you remove the gaiter the top part of the exposed tube will be all rusty. many will sand this down and hit it with some chrome paint. It is high enough that it doesn't affect the performance of the seals, but it is meant to be covered by the gaiter.

When you see a K1 with the dirt bike look, they have either done as mentioned, painted the top part of the exposed leg, or replaced the tube altogether with one chromed all the way, like from Frank's Forks.

As to the dust covers, I don't see how one seal can fit all. There were significnat changes in the lower leg throughout the years 70 to 82.  Those don't look like what is generaly used on the K1. You need a dust cover that pops over the outside of the lower leg. Those look like the type that pop into the inside of the lower leg.

Maybe they know something I don't?

[henrikm]

Thank you for your thorough reply. I took the gaiters off just now, and it seems like I need to spring for a couple of new forks, the top part looks like it's beyond salvage. I might try to sand it down and check how much I can get rid of. What am I looking at $-vise for a new pair? And will forks from later 750s fit my front end?

Edit: I see David Silver has them for $108 a pop 

[MCRider]

Thank you for your thorough reply. I took the gaiters off just now, and it seems like I need to spring for a couple of new forks, the top part looks like it's beyond salvage. I might try to sand it down and check how much I can get rid of. What am I looking at $-vise for a new pair? And will forks from later 750s fit my front end?

Edit: I see David Silver has them for $108 a pop 

Those may be the same as original in that they may not be chromed above the level where the seal rides. Check it out.  To be sure you get chrome all the way, Franks Forks  http://www.frankmain.qpg.com/
Is the stateside choice, about $250.  Now we're talking about spending a lot of money for looks right?  Your fork tubes are actually fine, you just want to change the appearance?

Nothing wrong with that, I've done it, but I'm just checking your motivation.

Later fork tubes won't work for a list of reasons. The K1 internal parts are completely different than the later ones. Changing the complete fork legs get into wheel, brake, fender spacing issues. I'd stick with the K1 and replace the tubes.

[Old Scrambler]

Those ebay seals look like the units that fit inside of the "ears" immediatly below the lower tree. Try searching for a dust 'cover'...............your fork tubes actually look good for their age. MCRider is correct on staying with the K0-K1 tubes to match the legs...............if you want the clean look you may consider later complete frontends from '75-'76 CB750F models.

[MCRider]

Actually if you want to keep the fork ears, but go gaiterless otherwise, you just use the same dustcovers from the lower legs (XL250) on the bottom of the fork ears.


These are Franks Forks tubes BTW.

[henrikm]

about $250.  Now we're talking about spending a lot of money for looks right?  Your fork tubes are actually fine, you just want to change the appearance?

Nothing wrong with that, I've done it, but I'm just checking your motivation.

Simply for cosmetic reasons. I'm building a vintage racer (think cafe, but without the hipster-off-the-shelve-seatbump-look). 250 + at least 100 in shipping to Norway is a tad high. I'll try to refurb the ones i got as good as possible. The lower case will be painted/powdered. Still need the dust covers though, will try to search for covers instead of seals. Se attached pic for the front end look I'm after.

Thank you very much guys, enjoy this community already.

[MCRider]

Ooh that's a good looking bike.

sanding and painting will pass the 5 foot test. (From 5 feet it looks real good.  )

The dust covers from a Honda XL250 are the quickest route. Not a perfect fit but darn close and will pass a 2 foot test. I'd bet money that's what the bike in your picture has.

Also, the dust covers from certain models of 70s era Harley Sportsters fit. In fact the packaging implies they are the same as the XL250. You have 35mm tubes, that's one dimension. The other is the diameter of the top of the lower leg, and that changes.  And where the lip is located.

If you can take your leg into a honda shop and ask them to try on a few. The 70s era dirt bikes are what you're looking for.

Also certain Yamaha dirt bikes. The bike in my avatar has OSSA 250 dust covers.

These are XL250

[henrikm]

I found 35mm covers on Dime City ($9) so I placed an order for those and a seal set. Starting the refurb of the tubes and covers tomorrow.

[jonmavko]

Hi There,

Wondering if you eventually found success with fork dust covers.  I'm in the middle of a 72 750 build and have been having issues finding ones that work.  See the photos of the last ones I bought, that cracking started happening after 3 months.  Bought them off of eBay.  They had an interior diameter of 55mm at the base, what I thought was large enough to fit over the top of the fork sliders. 

Need some guidance here as this is the 2nd pair that has cracked on me!  Thanks, all!

[bryanj]

Honda 500 twin ones should fit without clips

[PeWe]

David silvers fork tube to the later K2-K6 is chromed all the way. Same brand as I bought from CycleX a few years earlier.
Wemoto has promising fork tubes from Tarozzi which is an old quality brand. Make sure to get correct type. Wemoto has reference to frame number.
https://www.wemoto.com/search?q=cb750

Shipping UK to Norway is probably cheaper than order from USA. David Silver UK has max shipping cost at £19.95 when order more than a few parts that do not fit small box at £7. You can ship a lot for the max shipping cost. At least to Sweden. I ordered k2 seat, fork pipes, 2 rims and some small parts. Same shipping from USA should cost a lot more.

Wemoto shipping will be available just before the last step in checking out. At least for a few years ago.

Purchase Honda dust seals if not using gators. I bought aftermarket (from Cyclex if my mind is correct). They dried and cracked after 3 summers. My old Honda ones my bike got 1984, removed 2012 had no cracks.

[tlbranth]

I like gaiters and put some BSA mdels on my GL1000. I've read on several forums that unprotected forks are 'in for it'. Dust, bug juice, rain.....take their toll. Newer bikes that don't have gaiters usually have some kind of shield for the upper fork to protect them.

[KuangGradeMark11]

Hi chaps

I am in the process of doing (another) David Silver Spares order.  I have early K2 cycle parts on my bike (frame number is 2091918).  Until I can afford to replace my fork tubes and find some fork ears and a new front guard (mine are effed) I have cleaned the forks, ditched the gaiters and am just going to ride it for a bit.  It sure ain't pretty but it would be serviceable.

In terms of the advice above, that Honda CB500 Twin fork dust covers will fit, I just wanted to check if anyone knows that this 500 Twin cover will fit?

https://www.davidsilverspares.co.uk/CB500T-500-TWIN-DOHC-1975/part_210834/

Unfortunately DSS dont supply dimensions. Thanks in advance