85 350X Rebuild

[wonderboy]

Got the motor pulled tonight after work, and got the side covers and top-end stripped off the motor. Gotta get up early for work, so the rest will wait until tomorrow (after work). I hope to be able to split the cases tomorrow. On the bright side, the side cover and cylinder base gaskets didn't stick.

I did find a cool animations to understand how the shift forks move when shifting: https://www.youtube.com/watch?v=vq11CusULlk

I confirmed that this general pattern is how the 350x trans shifts by looking at a spare shift drum that I have. You can see how the grooves move the left, right, and center forks generally in the pattern shown in the youtube video. Kinda cool...

[wonderboy]

So I got it all apart. As I pulled the left case half off of the right (with the engine laying on the right side) the shift drum fell down due to having the shift mechanism removed from the left side. So this erased any possible evidence if one of the shift forks wasn't engaged on the drum. I put the case halves back together after making sure that the forks and shift drum were all aligned properly. I tried shifting it and turning the trans input by hand... it still misbehaved. I noticed that the double bump on the star wheel that holds the shift drum in neutral wasn't hitting the stopper arm when in neutral. If I shifted down as many times as it would go (supposedly to 1st), the double bump was about 2 or 3 notches away. Removing the drum center confirmed my ultimate mistake. Somehow the index pin didn't hit the groove in the drum center and the shift drum was simply getting indexed in the wrong spots.

Bottom line, I could have fixed this without even taking the motor out of the machine. Oh well. I just need to put the top-end back on and then the motor will be good to go.

[wonderboy]

Well, the warm weather is upon us, and I'm dying to get the machine back from storage to work on it.

To catch up the thread (sorry, no pics) I got everything back together last fall but had a HECK of a time getting the brakes bled properly. I ran out of time to continue troubleshooting before I had to claim back the garage for the winter. So, the machines went to the folks house for storage over the winter. I'll be picking them up on Easter and hauling them back to my place.

So, I couldn't get a solid pedal on either the front or the rear. I had the entire system torn down and have replaced all piston seals, master seals, new front brake hose, same old rear brake hose... nothing I tried could get a firm brake feel. Just to confirm, I rode the machine slowly and jammed on both front and rear brakes. The machine slowly crept to a halt. NO GOOD.

Things I've tried:
* Conventional brake bleeding, complete small bottle of brake fluid - No improvement
* Mighty vac (hand vac) on bleeder - No improvement
* Electric Vacuum pump (mighty vac on steroids) on bleeder - No improvement
* Tied front brake lever to the handlebar overnight and then bled - No improvement
* Electric vacuum pump on plate placed on top of master cylinder - No improvement

I even removed the complete system intact (master, hose, caliper) and tried laying it out on the bench so that the bubbles could run either back up to the master, or down to the bleeder more easily - No improvement!

It is driving me nuts. So, to start off, I'm going to remove the brakes from the machine and tear everything back down and look for anything I may have done wrong (maybe master cylinder piston lip seal folded wrong way, etc).

What is your favorite way to bleed these brakes? I've read on-line about a million different ways, but so far I'm striking out.

[Aulbaugh]

I've been wondering about this build. Glad to see it coming back! I have had success using the harbor freight brake bleeder kit. I had an issue on my front being spongy after a new rebuild. Turned out to be the aftermarket hose. Are you running oem hoses?

[wonderboy]

I splurged and got the reproduction new front hose from Vintage Motorsports. So, it is a brand new hose and I'm assuming not the problem... however, it definitely is an unknown.

Since I'm taking the entire system off the machine anyway, I saw something that seemed like a cool idea to isolate the problem. A guy was working on a car and isolated the master first (by clamping off a section of rubber hose coming out of the master then seeing if the pedal (handle in this case) was firm. Next, he clamped off the hose right at the caliper, confirmed if pedal was firm. After confirming firm pedal all the way down up to the caliper, it led him to focus just on the caliper. At any rate, I'm thinking of trying to isolate the system a piece at a time to see if I can figure out master, hose, or caliper.

I do have a bleeder check valve on the way from Amazon which I may try as well, just to be able to quickly pump fluid through this thing and maybe get the bubbles out that way. We'll see...

[Aulbaugh]

Yeah I got a couple of hoses from Mike@Vintage Motorsports for some rebuilds. That was the aftermarket hose that I was referring too. I bled the front multiple times with that repop hose and always got soft brakes. I switched back to an OEM hose and boom braking power. I followed what Onetrackmind did and took mine to a hydraulic hose place and had it fixed. Before you disassemble the front caliper try an OEM hose, I bet you get your brakes back.

[Rob Canadian]

wonderboy. Old machines throw 'Pascals Law' out the door sometimes. It holds true and have run into a couple things.

Vacuum bleeding. I have seen it done wrong. Many times. Regular bleeding has always worked fine for me. YMMV

Regular brake hoses do flex a bit but your seems somewhat extreme. Yes I have clamped the line. Be careful. It can damage the line inside.

2 things. Are the slider(s) nice. free flowing? To much lub inside the slide can lock it up and can torque the pads back a bit too much. I read a recent article about a master cylinder being worn out. Guy put a new rebuild kit in it. Spongy brakes. Bled,bled,bled... The bore in the master was in good shape by his eye. No grooves. Turns out the bore was a bit too much oversized. With that said. It took more travel to build up pressure and the cup had to flex more to push the fluid. Resulting in a spongy pedal.

When you did the panic stop. Did the front brake lever pull all the way in and the rear all the way down. Bottomed out?

[Aulbaugh]

http://www.3wheelerworld.com/showthr...t=onetrackmind

Read post #104 and beyond.... you'll see some similarities.

[wonderboy]

http://www.3wheelerworld.com/showthr...t=onetrackmind

Read post #104 and beyond.... you'll see some similarities.

Darn, that sounds almost identical to my problems... it is gonna kill me though to cut up this reproduction line to steal all the goodies off of it to dress up a new local-made hydraulic shop hose. But if that is what it takes.

2 things. Are the slider(s) nice. free flowing? To much lub inside the slide can lock it up and can torque the pads back a bit too much. I read a recent article about a master cylinder being worn out. Guy put a new rebuild kit in it. Spongy brakes. Bled,bled,bled... The bore in the master was in good shape by his eye. No grooves. Turns out the bore was a bit too much oversized. With that said. It took more travel to build up pressure and the cup had to flex more to push the fluid. Resulting in a spongy pedal.

When you did the panic stop. Did the front brake lever pull all the way in and the rear all the way down. Bottomed out?

So, the handle pretty much goes to the bar. It isn't right. Everything is new and replaced (piston seals, dust seals, pads, pins, etc). Everything moves really smooth. With regard to the bore in the master cylinder, I do want to inspect that more closely. I'll see if I can get it measured up at work and see if it is in spec (I rebuilt the master with a new OEM Honda master kit too).

Thanks for the tips guys!

[tapper190]

can't wait to see this x on the Michigan trails!

[wonderboy]

I'm excited to get out this year! My brake troubleshooting is sorta getting less attention right now... I've got my brothers 250R project in the garage too, trying to get it all back together (currently in a million pieces).