Xj750 seca locked up 3rd gear

Hey Yall
I recently purchased a 81 xj750 seca. I rode a 250 honda in a parking lot about 3 weeks before and I was hooked. The 750 was $400 on craigslist and had a few problems but (supposedly) only 18000 miles. Second gear was gone (not pop out gone, never engages gone), and it ran really rough, I'm guessing mostly due to a DIY 4-1 exhaust that didn't fit right anywhere and a duct-tape style pod filter install.

So to tonight's incident. I was scooting around some windy backroads at 30 or 40 when the rear tire locked up. I managed to muscle it over to the shoulder. That was pretty darn exciting for someone who has been riding all of two weeks! It was stuck in third and wouldn't let the back wheel turn and wouldn't shift out. I finally got it out of gear by getting the engine to force it out. I putted all the way home in first gear (basically like a 500 lb 80 hp scooter).

I already have the replacement transmission that I got to fix the 2nd gear issue, so I just need to get it in there now. So I want to know what I may be looking at when I get in there. Do I have a broken shifter fork that just now got caught in 3rd gear?

Also, what damage could I have done to the shaft drive by locking it up like that?

Also, can I get at all the business I need to just by turning the bike over? I found a thread here that seems to say I can: http://www.xs11.com/forum/showthread.ph ... eadid=5090

Is there anything else I need to look for?

I will not start on this for at least another month, I'm a full time student and almost full-time worker, so I can't mess around.

 

curious as to weather, you were hitting the rear brakes?? Did you check the rear brakes for Delmanination??? this can happen from neglected rear brake pads that are very old??

 

No I was actually accelerating. I have not checked the brakes though. Also on the front I only have one set of pads :]. I've been riding this bike very gingerly, usually at night and never in traffic. I have the second set of pads, but I haven't installed them yet. I doubt it was the rear brake, as it was fine as long as I stayed in first gear.

 

Once you have the bike flipped over and the pan off and the side covers off you should be able to see whats going on.

MN

 

Where are you located?
Natan

 

Kansas City

 

Got in there today (finally) and there is indeed a broken fork, with various chunks rolling around. Is there a way I can pull the forks? It seems that I can get the gears out (according to the webpage I referenced), but I have no idea what to do when it comes to the forks.

 

Split the case "got-in-there" or did you just drop the sump cover?
You need to have at least a maintenance manual and if possible, a companion Haynes or Clymer to agument the pictures in the factory book.
Best of luck, a spare engine would be a whole lot easier to use as a guide but that would also negate the need to fix the POS beat engine you currently have. You could spend a lot of time trying to puzzle out the twisted pieces to determine what you need and where it goes. What is your time worth?
Best of luck to you on this effort. Incidently, you would need to split the case to effect repairs, you cannot change forks any other way.

 

I got in through the oil pan and shifter side cover. I have those manuals, but it's a little difficult to read, because they show everything coming and going through the top, whereas I am coming in through the bottom. I ordered a fork assembly second-hand off ebay, and I already have a transmission in much better condition to drop in, so hopefully once I figure it out I will have everything ready to drop in. I've been watching craigslist for the past 6 months for a motor, but the only ones that showed up had tranny problems anyway. I'm about a half-grad student, so my time isn't worth a whole lot, and wrenching on this demon-possessed hunk o' aluminum is a good distraction.

Since I'm in there and whatnot, is there anything I should look at or for, or any additional maintenance procedures I should perform?

 

Don't worry about the orientation of the engine, where everything is will become apparent when you open things up. The books will help.
Typical replacement parts include:
Starter clutch springs
Starter clutch chain guide/tensioner
ALL seals
This list is short but important. They are either dead, or dying. This is a stitch in time, trust me.
I usually will pull a few bearing caps and plasti-gage them to see what shape the lower end is in.
Glad to hear you have a donor setup standing by. You will need a big Torx impact bit to remove the output flange keeper plate (you can't get the case split without this step).

 

Well, fans, it looks as though I will have to split the cases after all. The bar that the selector forks sit on looks like it comes out through an opening only accessible when the cases are split. Bummer. I have all the parts I need for the fix, but I want to know how much time I need to set aside for this, as well as an idea of how difficult this is going to be.

 

A weekend is sufficient, or about 16 hours for your first venture into the case. It isn't too hard, just don't forget about the case bolt that is located in the oil filter boss!

 

I've gotten a bit deeper over the past two weeks. Everything is freed up, except the case will not split, and it looks like the stator assembly is the culprit. I really do not want to mess with the timing (my lesson learned from small engine repair), so I was hoping to leave all that as it was. Do I need to remove that allen bolt and take all that out? What is the best way to do that?

 

Use a Hand-Held Impact Tool
1/2" -to- 3/8" Drive Adaptor
3/8" Drive "Bit Holding Socket"
Allen Bit ( or Allen Socket )
Torx Bit ( or Torx Socket )

Have somebody hold a piece of wood to protect the Case from an errant blow to the Impact Driver.

http://www.sears.com/shc/s/p_10153_12605_00947641000P

 

when you get it apart it'll look something like this. my forks weren't broke just jacked up

 

I got it all opened up, one of the gears was missing 4 teeth, that explains the chunks of metal in the oil pan.

Another problem: there were a couple of screws that have fused with the bottom case because of corrosion. I was able to get everything apart by just drilling the heads off. Also, I was silly enough to use the security type torx bit, so it crumpled slightly and stripped two of the torx screws. I then broke a screw extractor attempting to remove them. All of this madness happened on the bottom case, so I was seriously considering just buying another bottom case, as they don't appear to be unrighteously expensive on ebay. Where do I find what years or vins will be compatible with mine?

 

http://www.yamahapartshouse.com/yamaha- ... ibrand=YAM

look up your bike to find the part number then look up the part number to see what other bikes use it.