Pilot Screw Hole

[Edward]

1978 XS400

Finally had time to pull the carbs out of the bike this last weekend. After researching the posts by the PO ( http://www.xs400.com/forum/showpost.php?p=99094&postcount=4 ), he mentioned that he messed up the Pilot Screw/Idle Screw (same thing, right?)

The screw was put in to far and the tips broke off, to remove the tips, he said that he drilled them out. I attached pictures, are the carbs too damaged to be used? Is that hole too big? Can I measure it with some calipers to confirm?

From my searching, those screws aren't super easy to source, so if the bodies are toast, I might as well search for an entire working carb.

In addition, I noticed that when I removed the carb, there was fuel spilling out of the air box hose. Is that a byproduct of the messed up pilot screw?

Thanks for any help!

Edward

 

[Edward]

Bump, also took pics of the screws, there should be pointy tips on them, right?

 

[arfstrom]

Hi there, I was checking Partzilla, and its hard to tell if your missing something. The 81 bike, has a washer, and a rubber o-ring. The 78 its not listed as having one. So there is a chance that your okay with your needles.



http://www.partzilla.com/parts/search/Yamaha/Motorcycle/1978/XS400E/CARBURETOR/parts.html

In addition, I noticed that when I removed the carb, there was fuel spilling out of the air box hose. Is that a byproduct of the messed up pilot screw?

Nope, I can say with certainty, that the pilot screw has nothing to do with the Airbox filling up with fuel. So what could it be? Float height, or failed float. Potential petcock not shutting off as appropriate. so as long as your carb is off. (PS dont forget to save your carb, and put a in-line filter onto your bike(if your missing one)

Good luck Tobie

 

[xschris]

Yep they are toast They can be drilled if you use a very small drill I think it is like a .045mm one. But you need to step it for a bit of a tapper for the needle to sit in. Looks like the p.o used a much large drill and put the old broken needles back in. Sorry

 

[drewpy]

don't drill, grind down a nail to taper and tap it through using a 2oz hammer.



Mikexs has the tips, not hard to find

 

[Scorpio1963]

I was thinking they look like toast to me also and theres that scratch or whatever it is inside the carb mounting onto the engine side.I also agree with the puddles of gas inside the airboxes or intakes you have an incorrect float hiegth.
Another thing I dont get it why do people try and drill things like brass out of a carb when you can use a reverse extractor.
XSCHris where did you get that drill bit set at?

 

[Edward]

Thanks for all the replies! I figured I would end up looking for a new carb, just glad I didn't spend any money trying to fix up this one. I wish the PO would have checked here before throwing a big drill bit through it!

I believe I should be able to get a 80-82 carb to work on my 78, according to this thread: http://www.xs400.com/forum/showthread.php?t=6459

Any tips or tricks in finding a good working carb?

 

[Scorpio1963]

Keep checking our classified section members often have carbs forsale.Other than that just make sure everything is there and bear in mind unless po has specified the set of carbs you get is going to rquire a good cleaning and adjusting.

 

[xschris]

I got them from ebay. I have done but the nail and the drill. I like the drill more because it don't touch the carb bodies at all just the brass needle. Where the nail tended to mange the hole The pic is of the .045mm bit and a small pin ( which was too weak to "tap" the broken tip through) The nail I used did push it through but made a mess of it. But if it works for some then have at it I know the tips can be broken off with different levels of broken, with some being just setting in the hole and some almost like welded in.