Greetings

Greeting

I’ve been lurking for a few weeks gathering info. Nice site LOTS of good info.
Found an 81 750 last weekend, runs a little (carbs, boots, sync, valves, etc).
Looks like 1 of the PO’s did a little, the outside boots look almost new, inside BAD!!
Stops a little no fluid in front, adding/bleeding looks like A LOT of fun!!

First question, do I really need a fuel filter on the vacuum line :roll: to the petcock?

albran

 

Welcome to you Albran, I'm not familiar with DFW.
As for Q.#1, no you don't really but it couldn't hurt. Remove at your leisure.

 

Thanks for the welcome DFW is Dallas Ft. Worth.
I'll have several serious questions in the next few days.

Brakes will be first to be worked on.
I've figured out why no fluid 8O ...Calipers need a little work, after fill and bleed front is locked UP.

Carbs will be next, I've never worked on Hitachi but have many many hours rebuilding/jetting Mikuni SO I'm seriously thinking about a Mikuni conversion?

albran

 

Welcome. Not sure why you would want to convert - both carbs work the same and area bout the same to work on. There are some minor differences.

IF you have not seen these take a look.

Clean enrichment circuit
http://www.xjbikes.com/Forums/viewtopic/t=8918.html

Clean carbs
http://www.xjbikes.com/Forums/viewtopic/t=2908.html

Carb Sync
http://www.xjbikes.com/Forums/viewtopic/t=2132.html

Bench sync
http://www.xjbikes.com/Forums/viewtopic/t=6366.html

Float Height
http://www.xjbikes.com/Forums/viewtopic ... t+dry.html

 

That amigo, is a classic sign of a blocked return port in the master cylinder. Rebuild the ENTIRE brake system and be sure to get the itsy teeny weenie hole next to the piston inlet absolutely cleared of debris. Contact Chacal for reasonable prices for everything you need.

I would also question the wisdom of swapping over. You really don't need to if you have mastered the Mikuni. The differences are negligible enough that you should find that they are not any more challenging.

Fire away with the questions, just be sure to look up your questions before you post them, most issues you may encounter have probably already been covered.

 

Thanks for the blocked return port , but this may be only part of the problem.
I’ve take 1 of the calipers apart (almost) the piston has been pushed out of the bore so long that it’s corroded and won’t go in or out.

The reason I thought about a carb swap is I have a small assortment of Mikuni jets/needles, ets.
Now that I’ve started disassembly I’ll stick with H’s. They are surprisingly clean.
They’ve been rebuilt at least once I have 5 bowl gaskets!!
It’s a shame they have 120 main jets and I have a (very blue) 4 into 1 exhaust.

I’ve started a list of parts to order but we’ll be out of town for the next 3 weeks SO this party is ON HOLD.

We'll be spending a little time on the Vmax it's in Colorado.

Later and thanks
albran

 

Update and I NEED a little HELP!

Thanks to Robert for the blocked return port in the master cylinder.

But as I was afraid, BOTH calipers are FROZE UP. After hours of cleaning and soaking the pistons WILL NOT MOVE, which means I can’t get them out to rebuild.

Any and all suggestions on how to get the pistons out of the calipers will be VERY much appreciated!

Thanks
ab

 

IMHO the easiest way is to use a grease gun.
find a bolt to replace the banjo bolt (10x1.25mm I believe). unscrew bleeder valve ever so slightly, and pop the grease gun on it. pump a few times.. the grease will push that piston out, rust be damned.

if you go this route, make sure you clean every last bit of grease out... it's prolly not good for the brake system.

another method is to use compressed air, but you would be basically dealing with a pneumatic weapon at that point, and proper care should be applied.

 

This is an amazing place.

I have air so I’ll try that first.

Update later

THANKS a LOT!!
ab

 

I have taken many automotive calipers apart using compressed air, and an air chisel with a blunt tip to set up a vibration on the caliper. That did not work on my Maxim's calipers. The grease gun method, however, worked like a champ, and is more easily controlled. Good luck

 

stereomind is hereby issued 1 BIG ATABOY.
Sorry but only 1 ataboy, 1 caliper is now ready to be rebuilt.
But the other is stilll being stubborn.

Again Thanks to ALL

WARNING to any future readers of this thread:
"another method is to use compressed air, but you would be basically dealing with a pneumatic weapon at that point, and proper care should be applied."

I did and it's a good thing WOW!
ab

 

When using compressed air, I always loosely apply a c-clamp around the caliper, positioned so that it will catch the piston. Prevents the whole eye-loss scenario.

 

VICTORY

Thanks for the C clamp tip.
I've been pushing the piston in with a c clamp, taking it off, pointing the "pneumatic weapon” toward the wall and covering the whole thing with a towel.
Using the clamp sped the process up A LOT!

Now back to the real world:
I've contacted my broker to sell all the gold, oil and gas futures. :roll:
I'LL BE INVESTING in O-RINGS.

Has anyone found a cross reference for these 2 pieces of rubber that cost about $25.00 apiece?
We use automotive oil filters on our cycles why not caliper rebuild kits?

Thanks to one and ALL

ab

 

Actually, the rebuild kits are pretty cheap. Chacal, our resident parts wiz, prolly has them in stock. If not, they're always on ebay. They consist of the two o-rings and a rubber cap for the bleeder valve.

When you get your rebuild kits, make sure you scrape every last bit of crud from the channels that the o-rings sit in... A set of dentist picks (or something similar) comes in really handy for this job.