Refitting the primary chain after changing out the primary chain guide.

https://youtube.com/shorts/aMXEClZcjeQ?feature=share

Hi Guys, does anyone have any experience of refitting the primary chain after changing out the primary chain guide on a 1980 XJ650 4K0? I'm hoping someone can tell me if 18mm free play is ok or do I need a new chain?
TIA.

 

My 900f was like that. I changed it because it was near the oil spray nozzle. Most of the time it's driving the alternator rotor so it's surprising it wears so much.

 

Cheers Franz, thanks for the reply. I'd be interested in finding out how much of a difference in free play a new chain would have in comparison to my 18mm for the old one. Can you remember if your's tightened right up or was there still some free play? With the 18mm, mine looks to be still clearing the oil spray nozzle, but only just if you push it towards it. I totally agree, it's surprising it could wear very much at all given the relatively low load.

 

Watch @Mezzmo video 3:49 minutes in for the chain. It is best to change it and check the starter clutch when you are in there. There is still some free play but it is mimimal. Chain cannot be tight it would wear too fast I think.

 

Thanks again Franz. I'm rebuilding my engines to Mezzmo's video and I've studied it, and all the others, in detail, but, although it definitely looks more taught, I'm still curious to discover how much actual free play there is on a new chain compared to my chain's 18mm. There's no indication in either the official Yamaha manual or Haynes. I have two engines to finish rebuilding after fitting new chain guides so if I can't get a definite answer I will be buying a new chain and assessing the difference.

 

I didn't measure the difference when I fitted the chain unfortunately. Might be about 5mm free play but I am not sure, perhaps you can let me know if you change it cheers.

 

Chains don't elongate much (XJ750 the same) check this thread out by @cds1984 he might be able to give you a better idea of the new chain tension.

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

 

From the above thread. Still does not answer your question though. Check the other pictures you can see where the chain has been worn away the oil spray nozzle.

 

nice to hear from you again , Robbie, long time since you've been on here, i had the same trouble with the logging in thing, had to get a 16 year old kid to show me how

 

Likewise bensalf, nice to hear from you after all this time. I put the Xj650 in storage just before covid whilst I got on with some other projects. Six years later I dug it out and it took considerably more recommissioning than I expected. Had a few rides out then I discovered the primary chain guide had disintegrated. Got a bg job on now.

 

yeh i remember the silver tank, after you went on a test ride, which ,after all your hard work, decided to melt the paint

 

This chain was used but on a low mileage engine. Its well clear of the nozzle.

 

Are you both near Keighley? I worked there years ago passed through Skipton on my way there. Do you go to local rallies?

 

No. I live at Ingleby Barwick.

 

Yes a bit away then.

 

im in Barnsley, maybe 40 mile away

 

I worked with Kone in Keighley many years ago.

 

It was 6mm. Yours very probably was 5mm. I'm glad I waited and ordered a new one in the end. Thanks for the help and advice Franz.

 

I am reading your other post on this cheers.

 

6mm as above