Don Burgoyne
Powerage496
Newby question, sure it's been asked before, can I use later model intake/carb holders on my XS2 for use with a vacuum gauge to adjust carbs?
Don Burgoyne
Don Burgoyne
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XS2 Carbs
- Thread starter Don Burgoyne
- Start date
yup, there is a capped threaded port on the carb bodies you can thread a vacuum adapter into also.
The later adapters won't fit with stock 72 air cleaners.
The later adapters won't fit with stock 72 air cleaners.
I don't think that vacuum port on the carb body appeared until later, maybe in '75 or '76. You can use the newer manifolds with vacuum barbs but be aware that they are angled differently than your originals. If you're running pods, that won't matter but if you're using the original airbox set-up, the carbs may not align properly with it any more.
Don Burgoyne
Powerage496
Thanks, the bike is staying mostly original, will look into the threaded ports on the carbs, I seem to remember that Motion Pro makes fittings for this, anyone used them, also will this work on my XS1B too?
Don
Don
There are no threaded ports on your carbs; 1976 was the first year for that feature. It may be possible to tap into the venturi and install plugs/barbs; I'll take a look at an old Solex-marked carb and get back to you.
You can drill and tap under the intake on the head for a barb as I have done on my 72. I used a small 90 degree attachment and modified a bit to fit. Then tapped by hand without taking the engine apart. You do have to take the carbs off.
As I recall... The 70 and perhaps the 71 have a port connection between the cylinders cast into the head so you can't do a vacuum balance with the carbs on the bike.
OK, Don, this may be a fix. On the bottom of the intake spigot of each carb, you should find a flat boss with a brass plug in it. The plug covers a hole that opens into the spigot behind the throttle plate; that's OK, you can read the vacuum either behind the throttle plate or in front of it. Drill out the plug and tap the hole for a pair of 6X1.0 mm. barbs. When not using the manometer, install copper sealing washers and 6X1.0 mm. blanking plugs.
That isn't the handiest location for the vacuum takeoff, but it's what ya got; the flat surface provided by the boss is a must for sealing the plug. You may need an elbow in your manometer line to keep it from kinking.
gggGary, you're correct, there are spigots for a hose that links the intake tracts on XS1 and XS1B heads. It shouldn't be much of a challenge to remove the hose and plug the spigots for tuning, though; just install two separate pieces of plugged hose.
That isn't the handiest location for the vacuum takeoff, but it's what ya got; the flat surface provided by the boss is a must for sealing the plug. You may need an elbow in your manometer line to keep it from kinking.
gggGary, you're correct, there are spigots for a hose that links the intake tracts on XS1 and XS1B heads. It shouldn't be much of a challenge to remove the hose and plug the spigots for tuning, though; just install two separate pieces of plugged hose.
Newby question, sure it's been asked before, can I use later model intake/carb holders on my XS2 for use with a vacuum gauge to adjust carbs?
Don Burgoyne
Don't use a vacuum gauge, use a manometer (make it yourself for about $6 to $8). A manometer is much more accurate for doing a sync on the carbs.
Don Burgoyne
Powerage496
Like I said, THANX GUYS!!!!!
Don
Don
Couldn't you run the manometer off this point?
CalsXS2
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Take a look at this post and it will show you where to drill and tap. I posted some pictures a while back but I can't find the post. Copy this and past it in search.
Question on carb holder air barbs
I will post some pictures of mine tomorrow.
Question on carb holder air barbs
I will post some pictures of mine tomorrow.
CalsXS2
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I like the looks of that. Some pic's of it on your bike would be great. Thanks.
Good question. I did not think of that brass plug? on the carb. Not sure if other porting in this area. I think I used a Std thread. Not metric. I would have to check.
Probably no more than the later models with the molded port on the rubber holder.
CalsXS2
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That's exactly what I said,,lol.
I ran this mod by a friend of mine. He's an old school flat tracker. He thought it was a joke. He said just use the dead cylinder method. Then again, he doesn't like any of the thing's I want to do,,,,lol. He even said don't waste the $50 I just spent on a NOS rim. I should find one in the junk yard.
I don't listen to him about most thing's. He says I call him just to do the opposite of what he says. But seriously. He had a theory that on the later years the port was closer to the carb where it wasn't as critical. He says guys spend a lot of time smoothing out the head, and I shouldn't touch it. I said it's only about 1" different than where the later factory one would be.
Any thought's. Thanks
