starter chain guide

its been a long fun time since i needed to post on here, but the other day my dad was riding the 83 xj750mk and had the dreaded transmission only has first and neutral situation pop up on him.

I've roamed around here the last week or so looking at the replacement procedure for changing the starter chain guide, lots of good info, but nothing to recent. i still have a few questions though.

1) anyone know of a way to change this without splitting the case(i seen some discussion on this but conversations tended to stop about this point)

2) what type of sealant works best to re-seal the casings if i do split them

3) do i need to take any special attention to anything else while i'm in there.

Thanks in advance and keep the rubber side down! 8O

 

1. No.
2. Yamabond #4 or the equivalent permanent semi-flexible adhesive sealant.
3. Yes, lots of things. Most importantly being the application of the sealer and where NOT to apply it.
3A: You need a service manual, don't do this without one.

 

might as well change the cam chain guide while your in there

 

thanks for the responses.
i have a haynes manual, but its not as good as i think it could be.
yeah, gunna change the cam guides, all seals and starter guide.
the engine was running better than ever and the bike was lookin real good, this kind of thing really sucks, i did a rebuild on this engine(without splitting the case) just 2 years ago.

 

Hi there,
Just had exactly the same problem with my '81 750.
I now have bits of engine spread all over the garage while I wait for parts to arrive.
As to your question, I can see no way that the starter chain guide could be got at without splitting the cases. In fact, I split the cases, removed the starter clutch and the crankshaft. The only place I was able to save a bit of work was by dropping the big end bearings and taking the pistons and barrels complete rather than dissembling them completely. I won't know how successful this will be until I start putting it back together later this week.
One place I did experience problems was with the torx screws holding the starter shaft and the torx screws used to retain the bearing on the gear cluster shaft. They are a real pain. I got the correct sized key with a half inch drive and used it with an impact driver. Ended up shattering the key itself. Finally managed to remove the screws with a ratchet handle on a socket set. Not easy! The four screws holding the bearing in place I have still not managed to get out. They have been punched to secure them in position. The manual suggests drilling them out but I am having all sorts of problems with this. Any suggestions would be great.
Good luck with your stripdown and rebuild. If I can help with anything, give me a shout.
Best regards,
Pete

 

i just did this yesterday, those screws are fairly soft and they have a metal plate behind that is fairly sturdy, i just took a 3/16 drill bit and hit the pinged spot on the bolt and wiggled a little bit, then took a torx bit on an extension(t40) and it came out, except for one where the whole inside area of the bolt sheared off, took a drill bit and smoothed out the original grip pattern and drove a larger torx bit into the center(must be a tight fitting one) and it came right out.

 

split the case finally today, was having trouble removing the alternator so i left it alone, now i find out i need to remove the alternater, what size bolt do i use to press this off with, i have a bolt for the center shaft, i need to find out what size fits the larger diameter hole.

 

You need a M16 X 1.5
Make sure that the shaft that you put in first to push against allows enough thread to be screwed in before the tension comes on. The shaft I used ( a cut down bolt) was a bit too long and I pulled the threads out of the alternator rotor. I removed the rotor in the end with a pulley puller around the outside. Not a lot of room if you try it this way.
Hope that helps,
Regards,
Pete

 

i got it out, although probably not proper, could not find a bolt with the right thread, but i had a tap for a different thread size(5/8-11), so i retapped the hole to the size i could find and it popped right off(not recommended, but if ur cheap like me and dont want to buy proper tools, you can get it done)

 

I think we are dead in the water, as we was cleaning the crank assembly i noticed a tooth missing from the cam chain gear.

are these cranks still available from anywhere, or are we looking at buying a new motor??

 

also, are seca and maxim cranks the same?

 

Seca and Maxim cranks are the same, but you have to use a crank from a 750, all the other engines are different!

 

thanks chacal, i think i have a good lead on a seca crank and wanted to make sure before i jumped.

 

well, i still dont have a crank, traveled for hours yesterday cause a guy said he had an engine for sale, went and looked at it, he neglected to tell me the transmision was jacked up, and the thing looked like it was sittin in a pile of horse crap for 20 years, and he still wanted 300 bucks for it, i said screw that, so if anyone knows where a 750 engine(or crank assembly) can be found, let me know.