Engine.....Fuel System

[Mike Sal]

Pulled the sediment bowl & tank off this evening.  Both with lots of mud which used to be gasolene.  The quart of dark stuff that came out of the tank was doing it's best to convert to varnish.  I'll take the tank to a local shop tomorrow to get it boiled out.

You guys didn't tell me it's a real pain in the butt to pull the carburator off.  I ran out of time before getting if off tonight.  I'll have to dig out my odd bent wrenches to get that back side nut off.  I did notice that the front side nut wasn't snugged up to the carb flange & I could wobble the carb a little.  Not sure if this means the flange is warped or if the guy just didn't get it snugged down.
Mike Sal

[kartjockey]

I'm curious if yours has those unique locking nuts on your carb like mine did. Mine had a tiny little wire coming out of the side that would poke into the threads of the stud tokeep it from vibrating off.

[Mike Sal]

Do you mean your carb studs are drilled for cotter keys (or safety wire)?  The nut on the left side didn't seem to have anything special going on about it (it won't come all the way off without the passenger side nut being loosened also, as there's not enough clearance between the nut and the rest of the carb body. 

I'm just coming off a bout of stomach flu, so didn't work on the bike at all since yesterday.  Maybe tomorrow evening I'll feel good enough to get in there to pull the carb all the way off.  That passenger side nut is going to be a bugger.  Since I'll have to pull the engine mounting bolts anyway to get to the kick starter shaft nut, maybe I'll just go ahead & pull it out on the bench to work it over.  I really wasn't wanting to do a complete tear down yet, but ya know how that works.....
Mike Sal

[kartjockey]

The tiny wire came out of the side of he nuts and pointed into the threads of the stud so that if it tried to vibrate off the wire would jab itself into the threads and prevent the nut from coming off. Those carb nuts are in a close area. i think if you back them off a little at a time alternating from one to the other it won't be a problem. Mine had a belt guard that went under one of the nuts that i had to contend with. I'm in to being all original and re-used all my hardware. I had all mine re-plated and used them again to preserve originality.

[Mike Sal]

Pulled the carb off yesterday. disassembled & soaked it in fresh gas, then cleaned the parts tonight.  I felt good that the carb had a bunch of black crud, but no white corrosion.  The black crud dissolved really well & it all cleaned up like new.  Anyone else pay attention to the numbers cast into the bottom of the bowl?  Not sure if they're part numbers or date code numbers.

One thing I've got to source is the "packing" used on both ends of the gas line and used on the needle valve (under the nut that seals & holds it from turning).  All three of mine disintigrated during the cleaning process.  Not sure if they were leather or rubber.

Oh, and the nuts holding the carb did not have the special locking feature kartjockey spoke of.  They had internal tooth lock washers.
Mike Sal

[Ricks]

Pulled the carb off yesterday. disassembled & soaked it in fresh gas, then cleaned the parts tonight.  I felt good that the carb had a bunch of black crud, but no white corrosion.  The black crud dissolved really well & it all cleaned up like new.  Anyone else pay attention to the numbers cast into the bottom of the bowl?  Not sure if they're part numbers or date code numbers.

What are the numbers?  I have heard that Tillotson stamped the venturi size in there?  As in xx/32"?

[Mike Sal]

The numbers stamped in the body (on outside of the bowl) is MT57A.  The numbers cast into the bottom of the bowl are in a circle & are "209076" with "518" in virticle orientation the middle (the 1 is sideways). 
Mike Sal

[Ricks]

Do you think that could be 5/8?  MT 57A was the last carb used by simplex.

[Mike Sal]

It's possible it's 5/8.  It looks like about that size when I look down the throat.  Not sure if the picture will turn out or not.  Hmmm, I wonder when they started using the 57A carb.
Mike Sal

[Mike Sal]

Oops forgot the picture

[Mike Sal]

What did Simplex use for a throttle return spring?  I see an extra hole on the linkage, but I didn't see an obvious place for the other end of a spring to attach.
Mike Sal

[Ricks]

They didn't!

[Mike Sal]

Hmmm....kinda like built in cruise control huh....

I wonder if a guy could stick a coil compression spring on the cable inside the twist grip assembly?
Mike Sal

[Ricks]

Makes it easy to ride with no hands!

[Mike Sal]

I've not tried to take the throttle grip apart yet....any tricks or tips?  Dont' want to goof up the cable I can avoid it, as this one is in pretty good shape (I wonder if maybe it's been replaced somewhere along the line).

My handle bars are a little rusty (not too bad, but bad enough they'll have to have some attention.....I'm thinking of painting them black), so I'll have to take it apart sometime.
Mike Sal