82 Xs650 Special Float height? Info :)

Ok thanks. So that would be 25mm, +/- 1mm, yes? I measure from the gasket placement to the top of the float, yes? If so, then my float heights are fine.

I have told I am the third owner. The first two barely rode it. There are only 20,00 miles on it! So I guess that suggests this is the original carb. How could I know for sure?

And the reason I took off the carb to clean it is a sudden loss of power. It backfired a few times when I went to start it recently and I felt a gush of air where I held the choke lever. So if the float heights are correct then what caused the loss of power. Could the gaskets need better sealing?
 
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And the reason I took off the carb to clean it is a sudden loss of power. It backfired a few times when I went to start it recently and I felt a gush of air where I held the choke lever. So if the float heights are correct then what caused the loss of power.
The carb itself is seldom the cause of sudden loss of power. However, carbs getting blown off intake manifold is consistent with your description.
 
Here ya go...
 

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I think you have a couple of threads going....

Congrats on the reassembly, if that's what we're looking at, ready for reinstall?

Before you try to start it - given backfire - probably a good idea to clean and set gap on points.

Then ya gotta synch the carbs and check the timing
 
You're right. I didn't know the best way to get a reply. I should delete the other one but I don't see a way to do it.

Thanks for your help! Everything you just wrote - setting point gaps, synching the carbs and checking the timing - I have no idea how to do. I'm not mechanically inclined. I know how to clean and rebuild carbs - I learned that many years ago - and how to change oil but that's it. If you could walk me through it, I'd be grateful.

And should I use a gasket sealant?
 
What are we using sealant on?

A manual may be helpful regarding points. I'll see if I can find a link. But open the point (LH) cover and clean the points with folded over 600-800 grit sandpaper, spray with contact cleaner and, rotating the engine slowly by hand (rotor nut) move the small points plate to obtain a maximum opening of .014"
 

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Yes, those are '78-'79 BS38s. The "tells" are no overflow hose nipples on the bottoms of the float bowls and the internal float bowl vents in the bellmouths .....

LabeledCarbMouthsSmall.jpg


Just a couple things I'll mention - are you missing the angle bracket that ties the carbs together across the bottom? Or maybe you just haven't installed it yet? .....

Finished4.jpg


Also, you have the top butterfly shaped plate installed backwards. The larger cut-out should face the rear .....

34 Alloy Tops.jpg
 
What do I use to measure the point gaps?

I would love to learn all I can so that I can be driving a 50-year old classic Yamaha in 2029!

I'm thinking about the sealant here, but after jetmechmarty said "not ever", I looked it up and it many people agree. Nevertheless, here's a photo.
 

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As far as synching the carbs,
It's done with the engine running, right before you begin enjoying the fruits of your labor. You will do a BENCH SYNC as the last step before you install the carburetors on the engine.

Spend my money? What money?
This is going to cost money, but you're going to own tools. It might be almost as cheap to just buy this:
1662057981812.png

HOWEVER, not as rewarding.
 

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