Tyler643's 81 JX650

@Tyler643 ,

From your conversation with me.

Hi guys. I have a 1981 Xj650 that I got a few months ago and when I got it the speedometer didn't work but the wheel nut was pretty loose and I tightened that up and it worked great. Sense then I have put about 600 miles on it and the speedometer quit working again. So I checked it with the drill trick and it got up to about 30 miles per hour and spun the odometer. And I knew it wasn't the wheel nut because it now has the cotter pin like it should. I'm thinking it's the drive dog by the looks of another post. What do you guys think? And if that is it where would you find one? Thanks for the help

 

part 6 and 7?



CLUTCH, METER
341-25149-00-00
$5.49
$3.40

RETAINER, CLUTCH
341-25846-00-00
$4.35
$2.90

 

That looks like what I'm looking for. I am new to motorcycles. But know my way around a wrench. Is this a hard thing to do or pretty simple? Any tips or tricks? Thanks for the help

 

remove front tire and it drops into area where bearing sits under speedo hub

 

Hi guys. I have a 81 maxim 650 and Today I went for a short ride. When I started my bike it started just like normal and ran great for the first half mile. After that it wasn't wanting to idle or accelerate out of first gear so I pulled in a parking lot and it shut off and wouldn't restart. About. Hour later I went back to it and fired up and ran great for about a half mile to a mile. Then it did the same thing and I tried to limp it back home and it made a clunking nose and skidded to a stop and wound restart. I can get it in first gear and neutral but no other gear. I also tried to push start it but when I released the cluch the back tire locked up. Any help would be appreciated.

 

Sounds to me like either your gas tank cap is not venting or the valve shims are too tight. The cap needs to vent freely to allow air in to replace the fuel that is used, you can try riding with the cap open as a test. Have you checked the shin clearances? If they are too tight, the valves may not close all the way when the motor is warmed up.

You’ll want to use second gear to pop start, it takes a lot of torque to spin the motor over in first and having the rear wheel lock up if you try first is expected. Don’t use the clutch as it adds drag and makes it harder to push, just get a rolling/running start and kick it up into second from neutral.

 

I haven't checked the valves or gas cap. But the bike won't start now. The starter just clicks. It has done that every so often but seems to just do it once then start. But now that is all it will do. Sense this happen I have not been able to get it to start.

On the push start sense this happened. I can't get it in second gear. It will only go in first and neutral

 

Sort this out first, there are a lot of threads on starting issues and the service manual covers in detail how to check the safety systems. Tons of help here too. Might just be a bad battery too.

Both important for a reliable well running bike.

It's normal for the bikes to be hard shifting when it is not running, try rocking the bike around while you shift or spinning back tire with hand if on the center stand while trying to shift (not running of course!)

 

I am thinking it isn't just a starting problem or a valve or gas cap problem. Because the bike has ran fantastic up till this point. And all of this happened at the same exact time. Witch makes me think it's a combined issue even with the trans problem. Because I have tried everything with that and no matter what I do it will not go in second gear. But maybe I'm wrong. That is just my thinking

 

read this sounds like your chain guide
http://www.xjcd.org/emergency_guidectomy

 

That sounds like that's probably it. I think if that is the problem, it would be best for replace that chain guide. What do you think? Is that a pretty hard thing to do?

 

This could certainly be the cause of the shifting issue but wouldn't be related to the others. You'll have to pull the motor and split it to replace the guide. I would verify this issue before moving onto others.

The other issues with the motor loosing power, stalling, starting again only to loose power again and not restart/turn with starter over could be the result of low/no oil too. That is worst case scenario. You can remove the pickup cover on the left side of the motor (round with two JIS screws) and turn the crank with a wrench carefully to determine if the motor is locked up. If not then I would look into the guide issue first and then start troubleshooting the starter issue.

 

I know it's not an oil issue. I changed it 500 miles ago and make sure to check it before each ride. Including when it broke down on me. I will check it all out and let you know what I find. Thank you for the help

 

this will be of interest to you
XJ750 Engine removal and split - Pictures.

 

Well I figured out part of the problem. After more looking at the bike I found a hole in the block and cylinder. So I definitely need a new engine. But I'm not sure if the bike is worth it. I also still don't know about the shifting issuer. It's weird to me that it all happened at the same time. I've talked to a few people saying it maybe is just a clip or spring inside of the trans. What do you guys think? Thanks for all the help

 

I also found a engine pretty close to me without the trans. Is it better to go with one with the trans? It's also a yics and I don't think mine is. What are the differences? Would that even matter?

 

I don't mean to keep making a bunch of new posts but right after I posted the last thing. I decided to try holding the shifter all the way up and slightly rolling the bike back and forth and it popped right up into second gear. It will now go in all the gears. I'm even more confused than I was before. Do you think when the motor locked up it made something just stick a little? And would that say the trans is ok now?

 

maybe a chunk of something went into the trans to get caught between the gears

 

Ok. So do you think it would be best to tear into the trans even though it seems to be fine now ?

 

Follow the instructions in the guidectomy link provided earlier. It’s not uncommon for a chain guide to come apart in the motor and have pieces jam up the gear shift mechanics. You can also inspect springs etc. while you are in there. Removing the broken pieces will fix the gear shift issue but you’ll need to eventually split the motor to replace the guide as the chain will wear on the oil nozzle inside.

 

https://www.xjbikes.com/forums/threads/xj750-engine-removal-and-split-pictures.38545/

you could start by removing oil pan and looking at the gears

doing guideectomy you look in this hole behind shifter cover

with oil pan off you could flush it out from this hole and from oil pan side
then look at what comes out. if your chain guide has failed you Have to replace it before oil nozzle is cut down by chain.

 

would not bother with this motor. get a whole one. if you look up the cost of splitting motor all the gaskets a used motor makes more cost sense. and you could buy a 750 motor and put it in your 650 frame

then you have a motor to explore and may be fix. when you do the chain guide you should also change out the starter clutch

 

I gotcha. I'll have to do some digging when I get some time. But I did find a 81 650 that had 16900 miles that I'm thinking about getting and taking the good parts from both and making one really good bike. Because that one needs carb work. But my carbs are really good and working great. If I do that is there anything you'd recommend doing. Or just swapping the engine?

 

Engines are plentiful

 

I found the problem. It hydro locked. There was a ton of gas in the oil. I have started getting ready to pull the motor. But have a question. Is it better to disconnect the final drive at the u joint or pull the whole drive shaft out? Thanks for the help

 

If the engine is full of gas oil, just open the drain and empty it

 

I have drained all the oil. But there is a crack in the block. That is why I have to pull the motor

 

Oh—- that’s a whole lot more than hydrolock!
I’ve never even heard of an xj hydro-locking, either. My bet is something else catastrophic happened.

 

I don’t see how it wouldn’t be hydro lock. Because the oil was more gas consistency than oil consistency. But I’m no mechanic either. What else would it be with that much gas in there?

 

If the crankcase is filled right up, the liquids will push through the black tube on the left cover and flow up to the airbox will it will then drain through the small tube to the floor.

First off, hydro locking is primarily a “water filled a cylinder” issue. Rarely a gas/air mix issue. You’d almost have to have an injector fail and pump massive amounts of gas into a cylinder. Or, have head gasket fail and allow a cylinder to fill up with antifreeze. Or drive through some seriously deep water.

In order for the engine to be “locked”, you’d have to have a sealed crankcase, and/or a cylinder that is completely sealed and gasoline fills the chamber completely AND there’s no way for the fuel to seep back out..... or be filled with water.

It’s not a Diesel engine, so I totally doubt it was hydrolock

 

Tyler643,

Could you post a pic of that crack you are talking about? As stated above, if these is a crack then something mush more damaging has happened to the engine. It could be all kinds of things and yes you will have to crack the engine open. If the crack is there and you don't have a donor block, why would you even crack open the engine? Time to look for a replacement if this is still something you want to do.

 

I have a donor motor that is why I am pulling the motor.
If that is the case how would all that fuel end up in the oil at the same time. And the number 2 cylinder that cracked be the same carb that was leaking?

 

The gas in the oil is a normal thing to happen when the float bowl jets don't stop the flow of gas. The petcock will leak letting gas through or it is left on prime. The gas then slowly leaks into the engine. The gas then runs down into the oil sump. As for that crack, there is a lot going on inside that gear/crank area. If you get a chance to pull it apart to see if a connecting rod let go or the transmission blew up? I don't know if the battery and starter on these motorcycle could brake a connection rod, wrist pin or anything connecting to the crank? Is it strong enough to try to push through a hydro lock, I don't know I guess anything is possible. Most hydro locks I have seen will not give visible damage to the outside. You have to pull the heads or even the jubs to see if something is broken or let loose. Normally you can hear it when you try to hand turn the motor. Looking down the cylinders to see if all the pistons are more moving.

The crack in your case I am guessing is from either a engine full of water and froze or the trans or crank when when it was running. Wow....and good luck with the engine swap.

 

Hmm. Once I get it out I'll dig into it and let you know what I find. But I'm almost positive it's not water because it's always in my garage and it's been a long time sense I washed it or anything like that. I will let you know. Thanks