XS650B Questions

[Richy]

Purchased this 75 XS650b model , now being new to the XS world I don't know if everything on the bike is standard etc, ( apart from the few missing items) so I have a few questions for the more knowledgeable folk on this forum.
I have got the bike running, and have now completely stripped it for rebuild considerations, cause it can't stay like this!
The bike has spent some considerable years resting in a shipping container which hasn't done it the world of good, but that's what I bought.

Questions
1. Are the carburettors supposed to have a mount / support bracket between them ? these two are only connected by the 3 hoses.
2. As these carbs have a separate cable for each carb and no common shaft / join for the throttle bodies.... this means the only way to balance the carbs is by both individual cable idle adjustment ? this just just seams wrong.
3. I am trying to work out if the upper and lower triple clamps were originally with an aluminium finish or were they painted black? due to heavy alloy oxidation and liberal black out with paint and powder coating this is not easy to see. and lower is steel and the top is aluminium.
4. Both fork legs have a bolt lug at the top rear but nothing bolted to it, what is this ever for?

Any help will be muchly appreciated , thanks.
Richy.

 

[Jim]

Welcome to the forum! Hopefully someone will come along and help with your questions.
Meantime, there's a thread in the Tech section that deals with the differences between models. Have a read here...

https://www.xs650.com/threads/xs650...-other-information-including-xs750-850.30569/

 

[Jim]

Questions
1. Are the carburettors supposed to have a mount / support bracket between them ? these two are only connected by the 3 hoses.
2. As these carbs have a separate cable for each carb and no common shaft / join for the throttle bodies.... this means the only way to balance the carbs is by both individual cable idle adjustment ? this just just seams wrong.
3. I am trying to work out if the upper and lower triple clamps were originally with an aluminium finish or were they painted black? due to heavy alloy oxidation and liberal black out with paint and powder coating this is not easy to see. and lower is steel and the top is aluminium.
4. Both fork legs have a bolt lug at the top rear but nothing bolted to it, what is this ever for?

Any help will be muchly appreciated , thanks.
Richy.

I'll try and answer some of these, but I'm by no means a '75 expert.

1. I don't think there's a support for those carbs. Later models had linked carbs with a single throttle cable. They have a support. I don't think the earlier ones did.

2. You balance the carbs with the cable adjuster just below the throttle.

3. Painted black I think.

4. Not sure.

 

[650Skull]

View attachment 364650
Purchased this 75 XS650b model , now being new to the XS world I don't know if everything on the bike is standard etc, ( apart from the few missing items) so I have a few questions for the more knowledgeable folk on this forum.
I have got the bike running, and have now completely stripped it for rebuild considerations, cause it can't stay like this!
The bike has spent some considerable years resting in a shipping container which hasn't done it the world of good, but that's what I bought.

Questions
1. Are the carburettors supposed to have a mount / support bracket between them ? these two are only connected by the 3 hoses.
2. As these carbs have a separate cable for each carb and no common shaft / join for the throttle bodies.... this means the only way to balance the carbs is by both individual cable idle adjustment ? this just just seams wrong.
3. I am trying to work out if the upper and lower triple clamps were originally with an aluminium finish or were they painted black? due to heavy alloy oxidation and liberal black out with paint and powder coating this is not easy to see. and lower is steel and the top is aluminium.
4. Both fork legs have a bolt lug at the top rear but nothing bolted to it, what is this ever for?

Any help will be muchly appreciated , thanks.
Richy.

I'll finish off #4.
73-76 calipers had a steel tube component in the brake line. That bracket was/is where it clamps to.
On both forks so a second front desk can be added.

Welcome, bike looks to have good bones.

Link Jim posted has a carb ID link in it also around post #7 a few links to fixed for common problems

 

[magoo66]

Welcome Richy,you’ll enjoy your 75b.Looks to have great potential.The trees are black.Actually a matte black on the 75b’s I’ve had and it’s what I use when preserving or restoring one.Your choice if you want them glossy. The carbs do/did not have any connection bracket. I do still have a preserved original 75b.I’ll follow and help if I can.

 

[Richy]

Thanks for all the replies, that helps me on the right track. I have a service manual which is quite good but has poor reproduction photos, I believe I should get the Haynes workshop manual also.
Whilst the alloy hubs and wheels have considerable oxidation the spokes are beautiful stainless steel, although the rear wheel has been changed out with a Borani 16 incher.
As I will need to sand blast the frame, What's everyone's thoughts on powder coating or painting the frame?
Cheers
Richy.

 

[magoo66]

Richy, the decision of paint or powder on your frame covers a wide spectrum of pro and cons to either choice.IMO,the 2 factors to decide I’m thinking as you begin is how much of the project are you wanting and capable of doing yourself? The other of course is cost.

 

[Wagner73]

Thanks for all the replies, that helps me on the right track. I have a service manual which is quite good but has poor reproduction photos, I believe I should get the Haynes workshop manual also.

I have a Haynes manual and a factory manual for my 78E, and my nod would go to the factory manual. If your manual has poor photos, it may be a reproduction. You can probably find 75B factory manuals on eBay; failing that, there is a guy in NZ that sells very high quality reprints of a ton of manuals and the photo quality, etc is great. I have purchased service and parts manuals for 4-5 bikes from him. If I can find his info I will post it.

 

[Wagner73]

I have a Haynes manual and a factory manual for my 78E, and my nod would go to the factory manual. If your manual has poor photos, it may be a reproduction. You can probably find 75B factory manuals on eBay; failing that, there is a guy in NZ that sells very high quality reprints of a ton of manuals and the photo quality, etc is great. I have purchased service and parts manuals for 4-5 bikes from him. If I can find his info I will post it.

Stephen Reij, Motueka NZ
https://www.ebay.com/sch/i.html?_dkr=1&iconV2Request=true&_blrs=recall_filtering&_ssn=e-classicbike.com&store_cat=0&store_name=eclassicbikemanuals&_oac=1&_nkw=yamaha 650b

 

[Richy]

I'll try and answer some of these, but I'm by no means a '75 expert.

1. I don't think there's a support for those carbs. Later models had linked carbs with a single throttle cable. They have a support. I don't think the earlier ones did.

2. You balance the carbs with the cable adjuster just below the throttle.

View attachment 364677


3. Painted black I think.

4. Not sure.

Hi Jim,
And the choke then only operates on one carb ! Or do have something missing on mine?
The service manual I have does not show this detail.
Richy.

 

[Its been a long time]

Hi Jim,
And the choke then only operates on one carb ! Or do have something missing on mine?
The service manual I have does not show this detail.
Richy.

That's correct, there's a cross over tube to send rich mixture to the other carburettor. There's lots of slight differences on the BS38 carb sets depending on year. The carb guide in the technical section is an excellent read on this.