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Discussion Starter · #41 ·
Timing set to stock position.

Bike starts easily as before.

And runs the same as before. No power above about 4000rpm.

I was pretty sure it was the ignition, now I'm pretty sure it's not the ignition. It's not the air. Must be the fuel?

I think the next step is to pull the FCRs off the trackbike and see if/how it runs with those. The problem there is, I rebuilt those too so if I screwed up the SL carbs there's a good chance I did the same thing to the track bike carbs. They are jetted differently though, including different needles, so who knows.
 

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Discussion Starter · #42 ·
Today was the day. No procrastinating by playing around with other projects, it was time to switch the carbs on the problem child.

No big story there. The stuff I thought would be a pain was a pain, the stuff I thought would go ok went ok... except for the damn throttle cables.

With the original carbs the throttle would snap shut with nice loud crack. "New" carbs - not so much. The carb itself snaps back, the cables seem to be alright but when I hook the cables up everything gets less than snappy. It goes back, but not with the authority it had on the last set of carbs. I messed with it more than I wanted and think it's the throttle itself? Maybe. Whatever, it works well enough to test the carbs.

I finished hooking everything up. Stared at it a while. Found a wire that had come loose from a coil in all the jostling around. Turned on both gas petcocks. Let the fuel pump run a while. Worked the throttle four or five times. Pressed the start button... turns over but doesn't even think about firing. Turn off key. Stare at stuff. Wiggle this and that.

Turn key back on, work the throttle a few times, hit the start button.

Turns over, not a hint of firing.

Repeat steps.

No firing.

Grab a gas can, dump raw fuel into the carb mouths. Turn the key, hit the button...

And it's running. Not only that but it stays running. That's a good sign.

It sounds different? Softer maybe? Maybe it's just me. I'll have to find the carb setings for both bikes to see what changed. I know they have different needles and main jets, not sure about the other settings.

There's a lot more response to the idle speed adjuster. Now I can get something like 1000 to 3000rpm out of it. But it's not consistent. I'm not so sure that doesn't have something to do with the pokey throttle? I'm not going to worry about it for now.

Time to ride it. No seat, no fairings, no riding gear, no problem. Down the driveway, seems to be running well enough. Get it onto the street... roll on the throttle....

And it pulls to about 5000rpm before I let off.

Try it again. Pulls pretty smoothly to about 5000rpm again. I let off again. No riding gear... that's fast enough for now. Time to button up the bodywork, put on some gear, and go see just how far off the carbs set up for a 944 are when put on an 904 engine.
 

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Discussion Starter · #43 ·
And.... got the throttle worked out. It seems the tank hits the cables and moves them where they don't want to be, so with a little calibrated tweaking of various things it's working now. Still not the SLAP it had before but it snaps when it closes so good enough.

Rode it a little over 20 miles. It was idling around 3000rpm but I stopped and dialed that back. Ran it up to about 8000rpm with no issues. It's deceptively fast - I kept thinking it wasn't pulling all that hard and then being surprised when I looked down at the speedo.

Along with all the typical 90s Ducati noises the carbs chirp now too. Not always, it seemed like every so often when I'd roll into it they'd start chirping. I'd love to find some era correct FBF slip ons for it but that's not a high priority. Shoulda kept the fake Termis off my 851...

So yeah, it works. Knowing me I'll just put gas in it at this point, ride it and see what breaks. If it's anything like my 851 was this is just the beginning of the process. Over the winter I'll try to figure out what's wrong with the first set of carbs. And shorten the other throttle cables, put the stock throttle back on, etc. The jury is still out on what will happen with the donor bike.

The Corbin seat seems to be a good investment too. I was only on the stock seat for a few minutes but it wasn't impressive.
 

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100% TLDR for me.

With the FCRs are you sure they are not leaking fuel down the throat?
The "mid body" gaskets are a real bitch when they fail.
Went through all that with my DB4.


These guys are basically the only ones that supply the repair kit. I use them for almost all my carb parts at this point.
 
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