New bike, trying to figure out what's "normal".

Hey Everyone,

Picked up an 83 Maxim XJ650 for the wife (13,000 miles!), and was hoping to not mess with it too much before using it for a licensing test in September. Previous owner was conscientious, but not very knowledgeable. New tires, new front brake pads. I did an oil change, adjusted cam chain, and replaced the rear brake shoes. Spark plugs are a nice tan and I left them for now. Exhaust and intake look stock.

The bike starts easily, rides smoothly (up until the vibration problem below) and brakes well. (I'll do the stainless hose swap and take a better look at the valves and carbs in September.) But there's a few things I'd like to figure out:

- bottom end seems noisy, like there's a bunch of bearings swishing around in there. Is this normal?
- at 3500 in 1rst gear, and going up by about 600 for every next gear, it makes a crazy racket. I read the thread on the 5K vibration, but this seems way worse, and changes rpms depending on the gear I'm in. I've looked for loose bits, but only found the loose signal relay which tightening didn't make a difference. I haven't taken it past the racket, because it just seems that bad.
- the shift lever seems to have a grinding feel when I downshift into 3rd or 2nd gear.
- rpms seem to hang a bit when the bike is warm. If I pull in the clutch, it'll take 5 or 10 seconds for the bike to come down from 3500 to idle. The boots show cracks, but spraying carb cleaner on them doesn't present any air leaks.

I have a parts bike I've been tearing into, and getting the carbs unmounted is a bear! The bike seems great once I got to know its quirks, so I'd like to leave the bigger jobs for after the test, unless it's absolutely necessary. Otherwise, if it's "normal", or you can give me some oh-yeah-xj's-are-known-for-that insights, I'd love to hear them.

Thanks,
John

 

You may have a broken alternator chain guide.
Do this to find out.
emergency guidectomy

Removal of the parts of a broken guide (if present) is a temporary measure. Severe damage to a critical oil nozzle will result if the guide is not replaced in a reasonable amount of mileage.
The cases have to be split to replace the guide.

Drop the oil, check for broken bits of plastic, and get back to us about what you find.

 

Will take a better look tomorrow. Man, that is exactly the kind of thing I don't want to get into before September!

But in the oil change last week, there were no bits, and it shifts cleanly upwards, as long as I stay out of its shaky zone.

 

Checked the oil, no plastic.

Could this be a timing issue or a carb sync issue? I'm coming from a cb350, which is a bit simpler (and easier to get at!) I've never experienced out of sync carbs, so I'm not sure what the symptoms are.

Thanks,
John

 

Did you pull the shift cover? The chunks of a broken guide almost never show up in the oil.
Carbs out of synch won't cause a noisy bottom-end, or shifting problems.

The 5K vibration is felt, not heard.

 

Got it. Will try to get at it this weekend. Might have to park it for now and keep working on the CB, until I get the time and supplies to start from the bottom and get the whole "church of clean", valves, brake lines, etc. all in order. Thanks for your help.