Running rough

[5twins]

That looks like what's called an Ascot exhaust. Like most aftermarket exhausts, the headpipes are only single wall. That means they tend to turn blue, but usually only for the first 6" or so coming out of the head. The way yours is blued all the way down the front to the bottom bend indicates the bike was run too lean for a while. The way it mounts in the head may be correct for an Ascot.

https://www.mikesxs.net/ascot-street-tracker-exhaust-1974-79-xs650-standard.html

 

[crybinsk]

Big difference 'tween the two.... '72 XS2 was the first year with electric start. That installed on yours?

Yes but I haven't used it. I use the kickstart

 

[crybinsk]

That looks like what's called an Ascot exhaust. Like most aftermarket exhausts, the headpipes are only single wall. That means they tend to turn blue, but usually only for the first 6" or so coming out of the head. The way yours is blued all the way down the front to the bottom bend indicates the bike was run too lean for a while. The way it mounts in the head may be correct for an Ascot.

https://www.mikesxs.net/ascot-street-tracker-exhaust-1974-79-xs650-standard.html

That's weird because now it's running too rich

 

[Jim]

That's weird because now it's running too rich

Could be it was never properly sorted to begin with. also possible it's a take off from another bike that was too lean.

 

[crybinsk]

Could be it was never properly sorted to begin with. also possible it's a take off from another bike that was too lean.

You're probably right

 

[crybinsk]

Well, I can't say with 100% accuracy, but from what you've told us so far, it's a very good possibility, lol, especially if the P.O. installed a '73 rebuild kit. You can check the jetting by just dropping a float bowl, carbs still mounted, using a stubby screwdriver. That will tell you whether or not you need to go further. Both the main and pilot jets mount in the bowl on the BS38s. The main is under the drain plug on the bottom and the pilot is installed from the top .....

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The needle can be accessed by removing one of the carb tops and lifting the slide/diaphragm assembly out of it, carbs still in place.

You said you wanted to learn how to wrench, well, the 650 can be a very good teacher, lol.

Ok here it is.

 

[crybinsk]

Ok here it is.

And this

 

[crybinsk]

And this

Don't know if it matters but the gasket was on backwards like this

 

[crybinsk]

Don't know if it matters but the gasket was on backwards like this

Don't know why. Clearly it is the opposite

 

[crybinsk]

Here is the bottom as well

 

[crybinsk]

Final picture

 

[5twins]

OK, your bowls are the correct VM22/210 type and your pilot jet looks correct as well (a VM22/210 type). You'll just need to check the size. It should be stamped on the side. Stock size was a 25.

Next I would check the needle to make sure it hasn't been changed. You'll also want to check it's clip setting. The middle (#3 from the top) clip slot was stock ......

Lowering the clip (to slot 4 or 5) raises the needle and richens the mix.

 

[crybinsk]

I was thinking it all looked right as well. Should I take the carb completely off and reset everything? Make sure its all done right. Also does the fact that both spark plugs don't look the same. As in 1 was black and the other smelt of gas not give the impression that they aren't in sync? Plus the fact that the gasket was backwards makes me think what else is.

 

[5twins]

You still need to check the jet sizes (write them down) and what needle is installed in the slide. Check both the mains and pilots. Once you verify the jetting and needle clip setting, and change tt back to stock (or near stock), the black plugs should go away.

And that float bowl needs a good cleaning, lol. Lots of gas residue and varnish in the bottom. I'll bet the other one looks pretty much the same. And with all that gunk in there, there's a good chance the choke jets are plugged.

 

[crybinsk]

I'll do that when I get home. Should I pull the carb and set everything back to stock? Once I verify? As in would you recommend it

 

[5twins]

Well yes, but I'm a carb guy, lol. Normally, I pull the carbs and clean them on any old bike I get. But yours look like they could use some "love", lol. They're pretty crusty. I've seen (and renovated) worse but still, yours really could use a good going through and cleaning.

 

[crybinsk]

Well yes, but I'm a carb guy, lol. Normally, I pull the carbs and clean them on any old bike I get. But yours look like they could use some "love", lol. They're pretty crusty. I've seen (and renovated) worse but still, yours really could use a good going through and cleaning.

Ok thanks I'll do that. It's not running well so might as well clean it set it and tune it

 

[5twins]

Yes, please tell us what size jets are in it now, and what needle.

 

[crybinsk]

Yes, please tell us what size jets are in it now, and what needle.

I will do that over the weekend. I meant to make sure they are the right ones. Especially if I reuse them

 

[5twins]

Well, I can tell just by looking at it that the pilot jet was changed. An original wouldn't have the air bleed holes down the sides .....

It's OK if the jet has them, it won't hurt anything and they'll work just fine.

So, if you put everything back to stock and the plugs are still black, it's possible your original jets are worn. If they sit in old gas varnish for a long time, it will eat them away inside, making them larger and richer than they were originally.