IMscrews not the same?

[Gyrogearloose]

Well, now that I have cleansed the carbs of their broken IMscrew points, my next problem would be finding a new set. The old ones, broken and distorted, are only worth messing with if I can't find replacements. I'm not even sure that a new set would work without modification, since the holes their points enter have themselves been enlarged (distorted) during the broken point removal process. Hmmm. Anyway, the idle mixture screws TC and MRO referred to don't seem to match mine. ? My 79 Special (Ugly Betty) doesn't have caps or O-rings...?...just springs. First, could someone enlighten me? Second, are the IMscrews that MikesXS sells the right ones for my application? Thanks again for your replies.

[81xsproject]

That would be a big problem. The o-rings are supposed to be there. If they are not, they allow air to be sucked in through that hole which leans mixture. I think you will be fine with new screws. However, if the holes have been distorted, setting the mixture will be very specific to each cylinder, ie you wont be able to just set them all to 3 turns out and call it good. Many members have a Colortune including myself. Maybe someone will let you borrow one. I would let you borrow mine, but I am in the process of modifying it to work more efficiently. Your other options are to do Ken's 'by ear' method or Mike Hart's 'propane' method.

[fredintoon]

Different year, different screw.

Hi Geno,
1980 carbs have the needle with o-ring & washer. Earlier carbs (on the XS650 anyway) have different needles. Go here:-
http://www.mikesxs.net/mikesxs-fuel_...ategory_id=4.4
and scroll down the page to see different needle styles. There should be enough left of your fubar needles to see which type you need.

[red bandit]

If you have 78-79 carbs then there is no o-ring, they don't set down in the tube/tunnel. They stick up out of the top front of the carb body. Go to bikebandit.com OEM parts look up your bike, all 78-79 standards and specials take the same screw.
#33: SCREW,PILOT 20730-001 $14.06
That's a Yamaha OEM screw.

[DiverRay]

Gene,
The '78,'79, and EARLY '80 did NOT have the "O" ring type. MikesXS will carry the proper screws. Look for the late '70s carbs, as they should be the same. I would try and use a little bit of chrome polish on a Q-tip too try and clean up the base the needle go into. that should keep the new needles from getting "stuck" if it's distorted.

[81xsproject]

My bad I thought they all did. I am shutting up now.

[Gyrogearloose]

Hey there! Thanks loads for the information. Got all the points out now (had to push one through, as it WOULD NOT retreat back the way it came). O'well, do watcha' gotta' do..gonna try to form my own seat for that one, and fit/file the needle to fit it. ?

[TopCatGr58]

Hey DiverRay,

I believe that folks have tried MikesXS before, but they don't carry the right kind for the early model carbs ie. 78-79. They DO have the ones for the 80-81's that fit down inside the tunnel, but not the big head style for the external fitting ones of the 78-79.

Their part #s are quite different, see the prefixes!

2A2-14923-00-00 SCREW, PILOT xs11

2F0-14923-00-00 SCREW, PILOT 79 xs650sf

Gyro,
IF you haven't gotten your gaskets and such, then you can get a complete kit which includes the pilot screws here:
At CarbKitsCapital.com

XS1100 (1979) Carb Rebuild Kit
XS1100 (79) Carb Rebuild Kit. Includes the following, Float Bowl Gasket, Float Needle & Seat, Main Jet, Pilot Jet, Jet Needle, Mixture Screw & Spring.

Part #48-1972 $14.95 USD

However, if you just need the screws, the best price I recently found was at Zanotti Motors, a combo HD/Yamaha dealer!

https://www.zanottimotor.com/shopping/pLookUp.php
has them for $9.07 ea!

Just use the above OEM Yamaha Part # to search for and order online!

PGGG posted a technique of using JB Weld to seal the hole and then using the pilot screw to recreate the proper size hole, screwing it into and then unscrewing it leaving a hole, allowing it to cure/harden, then you can smooth sand the inside of the carb throat around where the JB weld is, just don't sand too much or you'll remove the whole hole!
T.C.