More Seca 750 anti-drive, ss cable questions

Hi all,
As per usual, I'll start my post by saying that this site is invaluable. Two years ago I didn't know a thing about motorcycles and now... well... at least I'm in third gear.

At any rate, this is basically an extension of comments I made on a recent post by NJrider.

I bought an xj750 from a guy for $180 CAD. Cheap because it had an electrical gremlin. That's fixed now that I've wired it up with a harness from an old Maxim and also changed the gages. The bike is fast and someone obviously put some love into her. She has stainless steel cables, an upgraded oil cooler, sweet fairing, powder coated frame, 4-1 exhaust, etc. That said, she's also been dropped on both sides. I've had her going faster than I care to admit on bad shocks and there doesn't seem to be any wobbles when the forks are properly filled with air. I think she'll be OK to ride.

Enter this weird front end with anti-drive system...

Things I'd like to address this weekend:

- Forks don't hold air. Does that mean I just need to put in new oil seals? I don't see any oil on the forks. I've got the seals ready to install. Will this solve my problem?

- She has steel-braided cables straight from a single master cylinder on the handle bars, into the calipers. Does that mean the guy has bypassed the anti-drive? (see pictures) Hillsy tells me this will make the braking weaker. What can I do to make it better?

- Sweet fairing, eh? I have the rest of the fairing to offer leg protection, though with some battle damage. Yet, the windshield is shot and temporarily replaced with a nifty skull license plate. I have a spare stock headlight housing and related parts, and I was thinking of just putting that back on and selling the fairing to someone who appreciates it more than I do. Is this a rare fairing? Is there a market for this?

 

Yeah, looks like the anti-dive was bypassed. This actually allows more brake fluid to flow into the calipers, since they don't have to share with the anti-dive valves, but obviously, you lose anti-dive, for what it's worth.

As the forks go... mix up some soapy water and paint it on liberally with a brush around the dust seals, around the fork tube caps, around the air valve assembly... Pump some air into the shocks and watch for bubbles, constantly re-applying the soapy water... It might help to have a buddy put some weight on the front end. I had the same problem, ended up being the valve itself... It's basically a tire valve, so they're easy to come by. Another potential problem are the o-rings between the air collars and the fork tubes.

Never seen that kind of a fairing.. Maybe it's the bottom piece of a bigger unit?

 

Somebody didn't like the fork mounted master and did the "upgrade" and also disconnected the anti-dive. Did they leave the anti-dive open to collect dust and water??

I don't recognise that fairing, maybe a couple more pics and someone will.

Make up some soapy water and find where the fork air leak is, if it's from the dust seal area, I think "yes".
Read Chorca's how-to on forks.

 

Actually, I didn't say bypassing the anti-dive will make your brakes weaker. I said it will make your front end softer / dive in more. If anything, your brakes will be sharper without the anti-dive.

That's pretty well the same set-up as my 750. The PO had removed the anti-dive lines and just left the anti-dive ports open. No big deal for me because my XJ is just a hack (sorry guys )

 

Oh- BTW, that fairing looks like a Suzuki item:

 

Re: time to ride's comment. Yea the guy left them open. Good point. There is now a bolt in them until I can take them apart.

It's definitely the forks that are leaking. Once I fix that, is there anywhere else air can leak from?

 

Several bikes from this vintage came with air-assisted forks. It puts more strain on the oil seals and often causes premature seal failure (might be where you are leaking air). Most rebuild their forks with Progressive springs, the proper preload spacer, proper volume/weight of oil and get rid of the air-assists. The anti-dive components changed the fork valving when brake pressure was applied so you might be travelling on max-soft setting as is. You could always clean out the anti-dive units and get short hydraulic lines to hook them back up.

 

They will be seized up and will need to be re-built. Probably not worth the time or money - unless you were adamant about keeping the front end original at all costs.