81 750 Seca new owner! Oy, it's a project

Greetings XJ gurus!

First off, I would like to say thanks to everyone on this forum for the knowledge and insight, it really helps. Especially for a first time bike owner such as myself. I included pics of the bike when I got it home, and as it sits now.

I recently acquired a new to me 1981 XJ750 Seca with unknown miles. Odometer says 35k, but that was before the speedo stopped working. The PO never bothered to fix it. I opened up the front wheel and discovered the meter clutch was lunched, so I replaced that (thanks chacal!). Bearings were good, didn't bother with those. Replaced all the cables (lubed of course) except for the choke.

With having snooped around this forum, I figured a brake overhaul was in order. Rebuilt both calipers, the (awesome remote cable actuated) master cylinder, and got some shiny new SS lines (xj4ever for the win!)

Here's where it got hairy today. I was going after the bleeder screw on the top of the left anti dive unit, and POP! Sheared the damn thing off!

Ok, this can be rectified, I assured myself. Attempted to extract with old craftsman screw extractor, just stripped the inside. Went to AutoZone, bought a set of spiral extractors. Drilled appropriate hole, inserted extractor, and twisted. Refer to image. I didn't take a lot of pics, but can run out and snap some if it would help the cause.

So, I went straight to eBay and chose a used set of forks off an 81 750 Seca. That's convenient! My plan is to rebuild, paint, blah blah those while keeping the ones I have on the bike, so I might be able to ride in the meantime.

Anyone have any suggestions on the best way of doing that?

 

Bike looks good ... Please keep stock airbox ... Pods are not worth the trouble !!! Good luck with your project.

 

If you want to save that anti-dive unit take the upper part with the broken bleeder to a machine shop. Whatever you do don't just throw it out.

Some reading for you:

Doing the 750 Seca's Forks.. (Rebuild.. now a HOW TO!)

Anti-Dive Fork Explosion

 

Thanks for the words, guys.

Wasn't even considering pods. I've read enough here to be deterred. The PO did drill a bunch of holes in top of the box, and it has a K&N filter, but I think I will get a stock paper filter soon enough. I'm not looking to try and build a racer, just a cruiser.

I'm not planning on tossing the anti dive. I actually used those links to help take
apart the left fork today, thanks. That's why I come here before I even attempt to turn a wrench on the bike!

Waiting for the SS lines from Chacal. Once I get those, going to plug the anti dive and run without them while I rebuild the forks and anti dive I'm getting off eBay. I'll post updates, in case anyone's interested.

 

Welcome aboard.

Gary H.

 

So, I put the new brake lines on, went to tractor supply and got a syringe and tubing. Proceeded to pump new fluid into the system from the left caliper bleeder, and there was an unusual amount of resistance. Fluid would not move up the system. I secured the tubing with cable ties, but it would still resist. I tried with the lever out and in, but nothing would work.

The master cylinder is installed where it's supposed to be, do I need to pull it out of its hidden cove while I inject fluid? Anything helps.

 

Did you rebuild the master cylinder?
Did you clean and rebuild the calipers?
Is the bleed nipple open?
Have you tried cracking the upper brake line fitting at the master until you get fluid coming out from there?

 

Rebuilt MC and calipers with kits from Chacal.

So, I got fluid to go from the bleeder to the MC, but only after putting the old seals back in the MC (they weren't really in bad shape at all). The new seals seemed so tight that the plunger would not return when engaged. I know that's what you want, is super tight seals, but it wasn't allowing the plunger to move.

That being said, there is fluid in the system now, but pulling the brake lever does nothing, with bleeders open or closed. Should I get a vacuum setup, i.e. a mighty vac, and pull fluid, and hopefully air, through the system to get positive pressure?

I feel like it shouldn't be this hard... Maybe I should look into replacing the MC with a handlebar mounted unit?

 

Did you put the seals in the correct way around? Did you make sure that the return port is clean? Did you make sure the piston bore was clean and lightly polished?

The 750 brake system is the most difficult to bleed, but once bled it's a good system.

For the final bleeding tie the brake handle to the bar, and use a vibratory sander to move the air bubbles up the system and out of the master cylinder. Start at the anti-dive units and work your way up each line fully, including the calipers and the distribution block.

 

Ok, so I got it figured out yesterday. Got fluid through the brake system, bled at the calipers where a significant amount of air came out. Finally got the pistons to move! Took it for a spin around the block and the brakes work pretty well. Better than they were with the OEM rubber lines. There is still a fair amount of play in the lever, but I attribute this to it being a cable actuated system. I plan on doing the sander method to expel more air after it sits for a minute.

The speedo works too! Only bummer is the backlight is out, so I couldn't see it in the dark. Installed an original headlight and bucket, which I got from a member here (I don't remember his screen name, but shout out to Marcos in Long Beach) because the headlight the PO had on there melted the wiring, I'm guessing because of wrong amperage. I'll post pics when I get home today.

As it sits now, it's a running bike! Can't wait to go ride! Now it's just some wiring cleanup and odds and ends. Even though I'm not planning a huge cafe or bobber type project, I'll post progress pics for anyone who's interested.

Thanks guys!

 

The cable is adjustable. You want about as much play as you have at the clutch (which isn't much).

The cluster bulbs can only be accessed by removing the headlight, and then removing the back of the cluster. If you have small hands you can remove the cluster without removing the headlight, and then remove the rear cover. The cluster nuts are below the top triple clamp.

 

Yeah, I tried adjusting the cable. I think there's still some air in the system that I will have to "sand" out. Went for about an hour long ride yesterday and she ran great. Well, nothing fell off, at least. Received my used forks in the mail, so I'm gonna start rebuilding those soon.

Attached is a pic as she sits today with the original light. Sorry, bad angle.

 

Looks good!
Going for that Midnight Seca look?

~Ghost

 

I've been planning to do a "what if Yamaha had made a 750 Midnight Seca...... Guess I don't have to now-- looks great.

Of course, maybe I'll do it anyway, and do some other stuff to it, too----

 

Thanks guys! I'm still new to this, so I had to Google "midnight Maxim" just to see what they looked like. I haven't done anything cosmetic yet, that's how I bought it, but I do like the blacked out look.

I was planning on keeping the gold accents on the wheels, but I got some brake fluid on the front one. I might be able to touch it up, though.

 

Shiny!!

 

So, bikes been running fairly well, did a fork alignment today because the last couple of rides it felt off/squirrelly. Haven't been able to test because I was putzing around and decided to look at my spark plugs. They all seem fine, but when I went to reinstall #3, I noticed it didn't want to catch threads. Shone a flashlight and the threads in the motor look marred up (pic attached).

It might be hard to see in the pic I took with my phone, but what is the best course of action to repair the threads? Just a kit from AutoZone? I'm headed there anyway to pick up silicone grease and polish because I'm practicing carb disassembly/cleaning on a set I got off eBay. (That's a whole 'nother post)

A gratuitous pic with the stock headlight included.

 

Looks nice , looks like someone almost made a midnight Seca
Alan

 

There's a repair kit available for fixing the spark plug threads. It comes with a thread cutter and repair sleeve. I did one with the head on the bike. It was a long PITA process but it worked. Use a piece of rubber tubing and a vacuum to clean the shavings out of the cylinder.

Here's the kit I used
http://www.ebay.com/itm/OEM-25649-1...dddaa5c5&item=201290589637&vxp=mtr&rmvSB=true

 

Cool, thanks. Never tried it before, so it'll be fun!

 

There was another one shown in a different thread a couple weeks ago. I had been watching that, as I have been thinking through how to create a 750rj Midnight Seca. Seems I'm behind that 8 ball, so I'll probably just pass on doing that, and continue with my other fun projects.....

 

@hogfiddles: You also have a turbo. Midnight Turbo?

Gary H.

 

650 turbo project. That will end up s a stock 650 turbo. I won't try to midnightify that......

 

Ok, so I put the thread kit in last night and waited for the rtv to cure for 24hrs. I was going to go for a short ride to test out my fork alignment skills (or lack thereof).

Alas, it won't start.

It started up at first, but was rough idle with a few soft backfires, then quit. I kept trying and it seemed starved for fuel. There is usually a small amount of fuel visible in the inline filter I put in under the tank, but now there is only a dribble and I can't see any moving through when cranking. There is gas in the tank, I looked.

The petcock is shot, I have a replacement I just need to rebuild (ordering parts this week). So the petcock has to be on prime for it to run. I replaced the vacuum line, so I figured it's an internal issue. My confusion is I didn't do anything to the bike since last time I rode it, except the spark plug threads. Could it be a compression issue? Like the threads aren't doing their job? If so, I'm in way over my head.

Anyways, it was starting to drain the battery, so I gave up. Any thoughts?