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Triumph TR5 - ZS CD-2 3150 Jet Height

I fixed a leak in my rear carb but while doing so, noticed that the threaded portion of the front carb's jet protrudes much further down than the rear. Muttering something like "Gee, Whiz" I pulled the air cleaner off and looked in the throats. The rear carb's air valve is sitting on the brass bushing that goes about 1/4" up into the throat. But the front carb's air slide is sitting flat on the bridge, with the jet sticking further out the bottom of that carb. Sheepishly, I can't recall the way it used to be - I suspect the rear carb has it right, with the bushing protruding into the throat, but I can't find a diagram of how the jet & ancillary parts are supposed to go together on the 3150 - closest I came was an old Clymer manual which should a pic for the TR-4 adjustable carb.

Futher note: that I can finger press the rear carb's jet, from the bottom, another 1/4" up into the throat. Releasing the pressure, the air valve will push it back down to it's normal 1/4" height into the throat, where it seats firmly. On the front carb, the jet assembly can't be moved one way or the other.

Does anyone know where I can see a diagram of how it's suppose to be put together? Anyone know where misc. jet parts might be available from? Considering Weber conversion but would like to keep the car original.
Henry J. Hruby

Turns out the jets on the CD-2 model 3150 carb are supposed to be removable, unlike later models. With the bottom cap off, the jet was apparently held in position by a) the upper O-ring and b) corrosion. I was able to press the jet out, and, after cleaning up the brass with a light abrasive - paper kitchen toweling; dry paper is quite abrasive - and a little solid parafin wax for lubrication, slip the jet right back into position.

Assembled, the jet is held in place by the threads on the lower inch of the jet tube being engaged by the internal threads on the disk in the brass end cap (also called the jet bushing screw). This will postion the jet about 1/4" up into the throat of the carb. Also raises the possiblity of adjusting mixture on this model by holding the jet tube slightly down while screwing on the end cap so the threads on the jet engage and hold it in a lower position. Hmmm.

Still need a diagram of the assembly however: if the jet is held in position by the internal threads in the end cap, what are the washer, spring and rubber seal that go around the lower portion of the jet tube used for?? Just holding the rubber seal in place?

FYI: I have a TR-250 with an early Comm. number - OD 323 LO. The 323rd built?? And manufacturing was still working out a few kinks while assembling this one....
Henry J. Hruby

This thread was discussed between 08/06/2004 and 09/06/2004

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