Right, was just out getting the fibre washer. Just have to source that thick brass washer now.

And the needle jet just taps out...?

Nothing to be embarrassed about! Thanks for posting pictures, that's always very helpful.

Needle jet taps out from bottom to top. That's why the washer is important.... keeps the jet from sliding up.

I like the Rick C. recommendation to use a chopstick as a punch... small dowel works too. You don't want to damage the threads.

Also, as was mentioned, there is a locating pin sticking through that engages a slot in the needle jet. You need to use a punch that is slightly smaller than the needle jet to avoid damaging the locating pin... Most of the time, once you tap the jet loose, it comes out the rest of the way pretty easy... if not, be mindful of the locating pin so you don't damage it with a too big punch and a hammer. See arrow on pic for pin location from outside.




One other thing is that the carb cannot be properly cleaned without the needle jet removed.

That's news to me on needing to remove the needle jet for proper cleaning, learn something new every day, thanks Mark!

I can imagine when you get this carb fully cleaned and reassembled correctly she is going to run like a dream, considering how bade a state it was in yet still running.

Yep, you'd be surprised how much crud can build up around the needle jet but more on the smaller carbs with multiple tiny holes through the column of the emulsion tube, & also the air jet looking in the mouth of the carb as it feeds air to the emulsion tube/needle jet. But once again not so much on these carbs as don't think they jet down small in there but have had a CS3E a lifetime ago that had probably a bit of air filter that found its way into 'that' airjet & total ruined my day at work--until i found it. Just another thing ya never forget haha. Ran crazy rich on the needle but only on 'that' one cylinder.
Re removing the needle jet. I use a very long 'think' 5mm screw & can pull it back in & get it timed right to find the side pin at the bottom. Happy days.

Yeeeeehaaaahhhh.... Carb clean, washer for the needle jet setter, new o-ring for the same... zing. Full rev-range pulling, even hints of a wheelie in first and second. Different bike. Thanks everyone for the input.

Minor drawing of attention to the matter of the o-ring, though. The 1.6mm section x 4.7mm id x 7.9mm od was actually far too big, although getting to know my bike it could always be that it has one or two, er, anomalies. Is that possible for a needle jet setter...? The wrong one installed...?. Spent an hour with a chap from Simply Bearings over here in the UK who eventually got somewhere close, but clearly it's worked.

However....

.... got to use fifth gear for a length of time for the first time, and, guess what? It jumps out of fifth every now and again.

I'm not even going to look at the book for that one - it's off to my spannerman - after I cover some smiley non-fifth gear miles while the sun's out.

Good news - surprised about the 'O' ring though. Maybe something to look into at a later date.

Outside chance that jumping out of 5th is the detent mechanism. Check out items 19 to 22 on the "Shifter 1" section of the parts manual. The bolt is on the underside of the crankcase and is often mistaken for the sump plug. The spring and cam stopper sit inside the hollow bolt.

Get some smiley miles in first though!

I received the same o-rings today and compared to the one I removed the new ones are definitely a different size.

What's the part number on the packet Pete? I'm just wondering if it's another Yamaha part supersession where the new part doesn't fit properly!

Alan, the sizes came from an earlier post in the thread, so they aren't a Yamaha part.
Having measured (as best I can with a vernier) I'd say the one I removed is 3.6 mm id with a 1.8mm section.

There are different o-rings for different bikes, years, models... I think the Danco #36 alternative o-ring was for the early AT/CT... doubtful a later DT used the same one.

Here's a post with some more info on "trade numbers" that might help.

yamaha-enduros.com/index.php/forums/74-7...b-carb-problem#67102