What have you done to your XS today?

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Had to go to work so I haven’t had the cover off the 81 Special for a while. When she’s backfiring I can feel a shot of air hitting me from a small pipe just to the left of the choke. Any thoughts appreciated
Cheers F.
 
Youre going to have to dumb that down a little (or a lot) should they normally have a tube attached? Can I ask why without looking stupid
Yes, a tube attaches and actuates a vacuum petcock, if the bike has one (or two).
If you have non-vacuum petcocks, we block them off.
To do the latter, I just cut a small piece of tubing and put a spent 22 cal shell in as a plug.
More on all this "plumbing" at this thread:
http://www.xs650.com/threads/installing-mikesxs-non-vacuum-petcocks-on-later-models.50124/

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Vacuum ports. The LH side originally fed the vacuum operated petcock to open it when the engine starts, and close it when the engine stops. The RH side was always capped from the factory on single petcock fuel tanks. Your bike now has a manual petcock that YOU open and close. So the vacuum port gets plugged. The plug needs to be of good materials and held on with clamps, 'cause a backfire can and will blow it right off the port. I like a ball bearing forced into a short piece of fuel line, many of the auto store "rubber" vacuum caps crack and leak in short order.
 
View attachment 149078 Well every day is a school day! Cheers guys
F.
Your bike looks great, especially with that nice background.
I spend a lot of my road time looking for such settings to take a picture of my bikes.
Here is a rural setting I discovered last year for my '83 Heritage.

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Vacuum ports. The LH side originally fed the vacuum operated petcock to open it when the engine starts, and close it when the engine stops. The RH side was always capped from the factory on single petcock fuel tanks. Your bike now has a manual petcock that YOU open and close. So the vacuum port gets plugged. The plug needs to be of good materials and held on with clamps, 'cause a backfire can and will blow it right off the port. I like a ball bearing forced into a short piece of fuel line, many of the auto store "rubber" vacuum caps crack and leak in short order.
I went and had a look Gary. There is a one on the other side and it is capped. I’ve put a piece of tube on with a large lead shot in it (bigger than SSG - swan shot gauge) bullets being hard to acquire in the UK.
 
I went and had a look Gary. There is a one on the other side and it is capped. I’ve put a piece of tube on with a large lead shot in it (bigger than SSG - swan shot gauge) bullets being hard to acquire in the UK.

I was going to say...a Brit going up and down the high street asking for bullets could get the local coppers....excited.
 
I went and had a look Gary. There is a one on the other side and it is capped. I’ve put a piece of tube on with a large lead shot in it (bigger than SSG - swan shot gauge) bullets being hard to acquire in the UK.
Can't wait to hear a ride report after that port was plugged!
 
Wow. You think it could have been something as simple as that?
Ya think?!? You don't know how lucky you are mate. Chasing down a "vacuum leak" can sometimes consume weeks or more and lighten the wallet considerably:( Not sure what passes for gambling in your neck of the woods... but while your luck holds, ya might wanna go do some wagerin'. :D
 
Ya think?!? You don't know how lucky you are mate. Chasing down a "vacuum leak" can sometimes consume weeks or more and lighten the wallet considerably:( Not sure what passes for gambling in your neck of the woods... but while your luck holds, ya might wanna go do some wagerin'. :D
I have to admit it’s given me a big lift to ride the bike in the afternoon sunshine without any problems. Signing up to this forum has certainly been a positive.
F.
 
Wow. You think it could have been something as simple as that? Just took her round the block (about 7 miles) tick over ok. No back firing and revved up ok no problem. That’s the first trip round the block without a hiccup since I acquired her a month or so ago.
F.
Don't feel bad, you aren't alone. When I removed the gas tank on the Radian I recently got I found the exact same thing. Guy had switched to manual petcock and never capped the #3 cylinder vacuum port. Ran much better after that.
And The old KZ1300's would blow off those caps like a pop corn popper.
 
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