Trying to rebuild these carbs, brass corrosion

[sjackson]

So after opening up my carbs over the weekend, I realized that I'm going to need to rebuild them. They were fairly clean inside, but you can tell that it's because somebody ran cleaner through it. Once you start taking things apart, you can see the varnish in between the pieces. Most of the brass parts have a thin patina over them. Also, the gaskets were for the most part melted and falling apart. Some of the brass parts are stuck in place, like the needle set screw and the primary nozzle.

Should I just clean these in place and leave them in the carb? I can't really figure out a way to get them out without damaging them or the carbs. They're not obstructed and all of the needles are straight. Also, when I put them back together should the needles on the vacuum cylinder be a little loose or should the set screws be tightened down?

Also, any advice for measuring the float distance? I don't have a special tool for it.

I've also discovered the most likely culprit. The screen in the aftermarket in-line fuel filter that was installed on the bike is covered in rust. It could be from the tank (which is starting to rust a bit and will get the kreem treatment) or it could be the screen itself rusting.

[Re-run]

Is it possible to get a picture to see what you mean?

[sjackson]

Sure. I'll take some tonight. The corrosion isn't that bad. It's just a dull patina on the brass. but it's got the secondary main jet literally fused to the needle jet holder. I didn't even realize those were two separate pieces until I looked at the service manual. Any attempt to separate the two would destroy at least one of the components.

[sjackson]

Okay, So here's the vacuum cylinder:



The needle is loose. They were all like that, so I'm assuming that's how it's supposed to be? (Never rebuilt a carb before)

Here's the view from the top down. That's the needle set screw inside there. I can't get it out. It will screw down approx 1/4 turn to tighten, but it won't back out at all.



Here's a good view of the corrosion on the overflow in the float bowl:



You can see that it's not too dirty in the float. Not spotless either. It was worse on Sunday. There was oily, sticky black residue all around the edge.

This is the needle holder pulled out of the needle jet:



It's got that dull patina on it. That little bit on the right end of it is the secondary main jet according to the honda manual. It's slotted on the end so you can apparently unscrew it from the needle holder. These two parts are completely fused.

And down in the lower hole, below the slow jet plug, is the primary nozzle.



This piece is also hopelessly stuck. You can't see it in the picture, but it's not clogged or anything.


So basically my question is, can I just clean these piece that are stuck in place? do they need to come out? Also, inspecting the #1 carb a little closer (the one in the pictures) I realized that even with the float all the way up, it doesn't push on the float valve at all. This would explain my gas leak and why it was running so rich. When the rebuild kits get here, I guess I'll adjust that float. I don't have a float gauge... is there any reason I can't use a speed square for this? Any advice on adjusting the floats on these?

Thanks

[sjackson]

So now I just got my K&L rebuild kits, and a few of the parts don't seem to match up. This just gets more aggravating with every day.

Any thoughts about these old brass parts though? Am I going to be okay to use them in their current condition as long as all of the passages are clear?

And what about those needles?

Thanks in advance.

[Re-run]

those parts are a-ok. I would use them in a heartbeat. I doubt there is any set of USED carbs that do NOT have that little corrosion. It is not really corrosion but deposits left behind I think.

[Myumi-2]

I'm not familiar with your specific carb, but there is a tutorial on carb re-builds at

http://www.salocal.com/sohc/tech/carb/carb.htm

I found this help-ful.  There was one for the 77-78 carbs as well, but Ive not been able to find it again.

Regarding the float height, there is a picture in the tutorial above which shows what the special tool looks like. It is pretty easy to do once you have seen a photo of someone else doing it.  And yes you can do it with a set square.  The problem with the set square is ensuring that both floats are set at the right height at the same time and that the square is parallel to the carb body.  I cut up a peice of cardboard to size, so that it looked like three sides of a rectangle, you sit that over the floats.  It looked pretty much like the part shown in the tutorial just not adjustable and made from the back cover of a kids school book.

Regarding the needle being lose, that is how they come.

The brass bits generally suffer very little wear and very little corrosion (as long as they are not exposed to water).  The main wear on the brass bits is caused by the use of a screwdriver when undertaking maintainance.  So as long as there is no apparent blockage or damage they should be OK to re-use, if you are not able to source an identical replacement.  

To remove the patina I'd just soak them in petrol, blow them with air and use a toothbrush on bodies.

Regarding cleaning the parts in place ... that does not sound like the best option.  But might be better than damaging the carbs???

Cheers
Tim