Fuel Tank liner(?) issues on new shiny '82 XJ750 Maxim

Got her all together, bled the brakes. Had a chance to use kmoe's awesome vibratory sander method, which worked incredibly well.

She's up and running, put a few miles on her testing things out.

No pulsation at the brakes and no front end judder! Yay! Very happy about that.

This takes me to a couple fairly minor electrical issues (that existed before but where inconsequential compared to the judder):

Low speed very sharp cornering causes the bike to die completely, instantly. Like, kill switch fast, no misfiring. Not all the time, and it requires a fairly steep lean, but it's happened twice.

I have to have the kill switch off (as in running position) and the ignition On to start the bike - this is as expected, of course. But to turn the bike off, I have to turn off both the ignition switch AND hit the kill switch. Either alone will leave the bike running. I'd hoped this would be clear once I dug into the front end connections, but they all seem normal.

Not sure where to look first for these.

 

Spent some time pouring over wiring diagrams, and at the mess of wiring a PO did when he replaced the fuse box, and I'm at a loss for the problems above. However, I'm not too bent out of shape about it as I'm very certain I want to replace the entire wiring harness with new, shiny, custom harness and simplified electrical system (as I've said elsewhere, I'm really certain I want to yank out the Atari).


Moving on:

I've taken it into work now - a 50k commute - and have a couple concerns.

There's a ticking - I assume valves, as it's clearly ticking and RPM based - that's most noticeable when the engine is hot. It's very faint normally, and I didn't pay any attention to it in my first shorter neighborhood rides, but when I've had it up and running at highway speeds for a while, it gets a fair bit louder. Not "OMG MY ENGINE IS EXPLODING" loud, but definitely noticeable. Louder on the right side of the engine. Is this normal?

The engine starts very easily when hot. Tap the start button once, starts and idles immediately, runs really well (amazingly well for a 35 year old bike with 80,000kms on it!) which helps reduce valve-induced terror.


I know I need to check them as who knows when they were checked last, but as I'll almost certainly need to replace the valve cover gasket, the donuts, get a tool, etc, it'll cost me several hundred after exchange/shipping to get into the valves the first time and I'm pretty broke. Just wanted an opinion on whether or not it's likely safe to ride in the mean time or if there's anything else I should check with regards to the ticking when hot.

 

Both the 650 and 750 had a TSB regarding slightly loose tolerances for the camshaft endplay.
It's a regular ticking that increases along with the engine speed, and is most noticable from the right side of the head when the engine is hot.
It sounds to me like that's what you are describing.
Ignore it.
No harm is being done. The camshaft endplay is not so large as to cause any damage.

 

Ah that could definitely be it. It's decidedly noticable, but it's not.. smashy. Something that raised some concern, but didn't sound so bad I feared riding it home. Thanks!

 

tighten the 8 nuts holding the pipes to the head.

 

Checked em, all snug.

Can hear it here:

https://goo.gl/photos/36y4WAuh86dtSyuJ6

 

you're fine, go ride

 

That doesn't sound all that good to me.............maybe the valves are really loose, or???

 

Haven't checked the valves yet. Buyin to get the needed stuff is out of my price range at the moment, so couldn't say. Be about a month. Only does that when hot though.

There was a scarier rattle, but that turned out to be the choke linkage, so not a concern at all.

 

This is much more noticeable here on the right side vs the left side, so k-moe's TSB is still a possibility too.

It sounds "valvey" to me, but I am unfamiliar with these motors and don't get why valves would get noisier with heat (wouldn't things expand and STOP ticking?)

 

Ok, on my last trip to work (half hour commute) I pushed the bike pretty hard on the way home, to investigate the noise a bit.

It's definitely louder when the engine is under load - loud enough that I'm pretty concerned. Oraybe it's just paranoia making it seem that way, but she's a 35 year old bike with 80k on her... A little paranoia isn't bad

Any tips for investigating major problem issues and ruling them out for peace of mind, such as piston slap, or rod knock?

I need to do my valves anyways, and have to repair a stripped valve cover bolt hole in the cylinder head, so tearing down that far may as well happen anyways. What should I look for when I'm in there? Is it possible to rule out bottom end problems from there, or would I need to tear down everything to check?

 

http://www.earplugstore.com/

 

I have 2 Maxim rotors 25$ for both if interested

 

Nice! I got one already, though, as I said in the quoted post, so I'm good. Thanks for the offer though!

 

Shoot a video and we'll have a listen. It's best if you can do this on a day with very little wind, and give about 30 seconds (per side) of hovering on either side of the engine. All I really ned to hear is idle, but of you want to run her up to 2k and hold it for a few seonds too, that will help.

 

Will do; should have it up tomorrow.

In the mean time, I took this a day ago after a run to the local gas station, by taping my phone to my gas tank. I don't have a proper mount, and this allowed me to get the mic near the engine and out of the wind - excuse the bizarre visuals of the ignition in the reflection of the gas tank. Kind of a scary thing to do, and got some really interesting looks from a cop watching me tape the phone down =)

The ticking isn't bad here, but it is noticable. I'm also concerned with the nasty rattling noise at 3500rpm - it's very clearly audible in the video at ~15s to 20s. I can't get this to happen when the bike is motionless in neutral, only when it's actually running. It's not the keys; I tested with the ignition off and the keys out (bike will keep running if the kill switch is set to run) to be absolutely sure. Thought it was the choke linkage, as it's very rattly when the choke is off, but that appears to not be the case. Tough to feel/hold stuff while accelerating though, so it's hard to test things.

 

I've got another uploading right now that shows the ticking under load better. Should be ready in about 40 minutes after this post:



Hopefully this does a better job of illustrating why I'm so nervous about it.

 

Hmm. I was going to say camshaft endplay, but then you really got on it.

Needs further investigaton.

It definitely has the camshaft tick, but then there is that hollow ringing sound. Hollow ringing is not caused by camshaft endplay, or valve clearances.

Hmmm......

 

It's rattly at idle (slightly over 1k rpm), which goes away if you give it even a teensy tiny bit of throttle. Whatever is making the noise there may be what causes the scarier noise at 3.5k; will try to capture it when I get the video tomorrow.

I'm thinking of a guy who posted valve cover pics that showed the cam chain wearing on the valve cover. Will definitely look for a worn/loose cam chain when I open it. I'm just spitballing here though, as I have no idea what can cause that. Really hoped it was the loose choke linkage =\

 

well... err... I found it.

The good news is that it's a simple fix. The bad news is it's deeply embarassing, as it's such a simple thing and it's horrifyingly obvious, but because I only really noticed it when I was already riding and generally accelerating, it was hard to hear where exactly it was from.

I was taking the requested video, got to the right side of the bike, as I finished I noticed there was exhaust coming out of the bases of both mufflers. I bent down to investigate further, grabbed the muffler... and... well.



I'm going to go hang my head in shame now.