There were endless variations. The short screen and tall screen carbed bikes had other differences, yet they superseded some parts all the way from short screen to the carbed bikes. I recall a bit of waterpump that looked wrong but fitted and worked.

Zero proof, but my feeling is that your choke plungers change the amount the lever moves? A solution to a problem no one really had?

Can you close the choke by other means? Shims and an extra O-ring?

A cold Rotax is impossible to start without but leave it parked in the sun and it will. If you can start it with the choke sealed off and it runs better you have the answer.

Thank you for reminding me how much I love my OBD reader

Andy

So I started on the carb rebuild(s) yesterday morning...dismantled each one completely and set the old parts into cups marked LEFT and RIGHT, just in case I needed to reuse any of them.
Put some HOT water into a small bucket, along with a few drops of DAWN dishsoap, placed the twin carbs into the liquid...closed the lid and mounted my B&D Jigsaw to the top with some Duc-tape...turned it on and left everything for 15 minutes in my homemade Ultrasonic cleaner.
Then, a quick rinse and dry with compressed air and then got down to it...everything was going great...turns out the the float valve I had installed to replace the worn one, was a bit shorter than the original...but it still seemed to do it's job, so who knows?
Had to reset the float level on that particular side....double-checked them both and set them to parallel with the carb body.
Idle jets supplied were #41.3, so I set the NEW mixture-screws to 3 ¼ turns (thought I'd leave myself a little bit of wiggle room) but the main jets were #140 so I put the old ones (#132.5) back in.
The slide guides are nice and new...but the emulsion tubes (venturi tubes) would not fit...they were physically too large to slide into their holders. I measured the diameter of the old ones: 7.02 mm
New ones were 7.06 to 7.09 depending on where I measured them. So I mounted one in a drill and spun it while holding some fine emery cloth on the threaded hub that holds the main jet.
When I had finished polishing off the silver coating, they fit like a glove! New needles with clips on the middle groove as per the manual.
Everything went together well, aside from the emulsion tubes...
Back on the bike a short while later...cranked her over a few times and she started (on choke) and took off on a higher than usual idle....good sign!
Let her warm up for several minutes and then kicked OFF the choke..she stayed idling...good sign!
Left her to idle for a few more minutes then started s-l-o-w-l-y opening the throttle....the hesitation/dip at 2000 RPM seems to be gone. RPM continued to increase, proportional to throttle position...I may be dreaming, but it looks as though the stumble between 3500 - 4000 is no longer there either, but I'll have to wait and test drive it first.
So now this thing has the equivalent of 2 new carbs on it...and I'm 99.9% certain that everything went together properly; there were no parts left over and no "old" parts used (other than the stock main jets and the choke plunger). At this point, I think it's safe to say that whatever problem may persist, it is likely NOT carb-related.
Still need to replace the spark plug boots before calling it done, but our impending holiday and the delayed delivery means this will have to wait for another couple of weeks.

Crossing my fingers...

great job - Sounds promising - that may be all of it solved! Ride it!

__________________
Grant Johnson
Seek, and ye shall find.
------------------------
Inspiring, Informing and Connecting travellers since 1997!
www.HorizonsUnlimited.com

Looks as though my enthusiasm was misplaced...

Got back from a couple of weeks holidays...was able to forget this albatross for a while. Got home and decided to change out the spark plug boots. That went easily enough; so now I have resistor-type boots with NON-resistor plugs.
She started easily enough and idled nicely while under choke...idling higher than usual which is good, but when I shut off the choke and tried to rev her up a bit...she wouldn't go past 3000 RPM....stuttering and coughing as if there were no more fuel.
If I revved her quickly, she would go over 3000, but not if I went "casually" as if I were driving.
After browsing forums for as long as I have, I suspected that the regulator might be the issue and sure enough....the Molex plug was hotter than a fire cracker and some of the wiring looked burnt. I tried to repair the Molex connections to no avail, then decided to scrap it and replace with bullet connectors since I have a lot of those.
In the end, I just decided to replace the voltage regulator.
Funny thing though...I've never had problems getting it over 3000 before...but under closer inspection, the Molex connections were quite cooked and corroded...as if this has been going on for some time. Given the age of the bike, I suppose the regulator could be defective...but why was I able to actually ride it for a while, if the reg was faulty?
I actually had someone coming to look at it this week...this means any potential sale will get postponed for another month (since I'm going on holidays again)...and parts won't be here for 2 weeks.
It's as if this bike is cursed...I know that people keep telling me that "once I get things worked out, it will be great" but as I explained to my wife; I don't trust this bike...I don't have ANY faith in its ability to get me to and from anywhere....and I've developed an outright hatred of it, as a machine.
My happiest day, will be the day I see it loaded onto a trailer and driven away.

Not that it helps you but the R/R is a known weak point. IIRC it's one of the bits like the chain and forks where Aprillia decided 125cc spec parts would be fine.

The gradual breakdown is always possible with analogue electrics. Works for a second, doesn't work, works again.... you only notice when the gaps are big enough.

The connector cooking is more symptom than cause.

Good Luck with the sale. Hope you find a masochistic mechanic who can get some pleasure taking it to bits over the winter.

Andy

Wouldn't it be something, if THAT was the problem all along?

This is the only bike I've ever hated...came close with a 2009 Kawasaki Super Sherpa once.

The next owner won't have to do anything...by the time I sell it, I will have worked out all of the bugs and THEY will get the bike that I was hoping for in March.

I once had a Rover 3500 P6 - beautiful leather, hand rubbed oak dash, smooth V8.

Would just stop. Randomly.

POS


Sent from my iPhone using Tapatalk

So I reasoned that if ONE side of the Molex connector was cooked and corroded, the other side must be too...so I installed bullet connectors onto the existing connections and fired her up just to see if it made a difference.

Apparently not, within minutes the regulator was too hot to touch, and the bullets were starting to heat up as well.
Good thing I ordered a new regulator....AND a battery.
I swear, this thing will be burning in a ditch somewhere soon.....

Replaced the voltage regulator today...didn't make one bit of difference.
The dead-spot between 3000 - 3500 remains...taunting and mocking me each time I start the damn thing.

I have NEVER hated a machine more than this one...

Does the regulator and connectors still get very hot? Is the electrical issue solved?
Leaving the dead spot to solve?

__________________
Grant Johnson
Seek, and ye shall find.
------------------------
Inspiring, Informing and Connecting travellers since 1997!
www.HorizonsUnlimited.com

The regulator gets warm...not as hot as the one I replaced.
The dead spot(s) come and go as they please...acting up today, will probably be gone tomorrow, only to return again the next day...this is the most frustrating machine I've ever owned.

It's official...this POS has broken me...I give up. I'll be looking for a shop to repair it over the next few weeks. Going on holidays and when I return, I'll be looking at getting a new Honda.....NEVER looking at another German bike again.

My riding season for this year is a write-off...all thanks to ONE unscrupulous pr*ck that sold me this POS.
I swear, if I could get away with it...............