34l missing at higher rpms

[suke]

I have a 1984 xt 600 34l tenere, that I'm trying to get running correctly again. The bike idles fine but once you get it revving around 2000 rpm and above it runs rough and seems like its missing. It also runs better when I'm accelerating but when I try to cruise at a steady speed/rpm it acts like its missing again.

So far I've gotten the stator rewound and the pickup coil checked, new ignition coil, new spark plug, I had the carbs ultrasonically cleaned and rebuilt and put a new air filter and none of these seem to fix the problem. I also replaced with the CDI with a hypertec one (its for an xt 550 but wayne said it had the same timing??) , because my problems seem to happen when the bike starts advancing the timing and installing the new CDI didn't make a difference either.

I'm running out of ideas as to what could be the problem. Are the CDIs interchangeable between all the xt 600s because I have a US model Xt 600 43f that I tried using the CDI from and my tenere still runs rough at higher rpms but will idle perfectly fine.

Thanks in advance for the help, Ben

[Eric66]

Hi Ben,sounds like you have covered everything electrical and fuel wise as long as the carb is set up correctly. The only thing I would suggest is to check the valve clearances as it may be carrying a valve ( clearance to small and the valve opens to early). Good luck, and put up some photo's of ya bike.
Regards Eric

[suke]

Sorry, for the late response, but so far I rechecked the valve clearances and I took the fly wheel off and valve covers and rechecked the timing to make sure that was all correct, and it still runs the same... I think I might look into the carbs again and double check everything to make sure its set correctly.

Mezo, I actually wasn't the original person to import it and it came with a US title and registration when I bought it. So, I have no idea as to how difficult it was for the previous owner to get all of that done.

And here's a pic of the bike as it sits now. I've done a bunch of work to it... just wish I could get it running good now

[ActionManMelb]

This will be hard to fix remotely!!

Think about how the ignition system works.....
There are two ignition firing pickups. One is used for starting and idle and is set to 12' BTDC.
The second takes over at 1500-2500 rpm and has a maximum advance of 32' BTDC.

Sounds to me that the second pickup is not doing its job. The best and correct way to check/verify and repair this is with an oscilliscope.

If that is beyond your technical expertise, then I suggest talking to your local bike shop.

[xtrider]

I just saw this , where in Wisconsin are you ? I'm in the dead center of the state. I have a pile of cdi's and carbs we could swap to narrow down which area is causing this.
The rough running at steady speeds sounds like excessive fuel surging. What main jet is in the 2 carbs ?

I could also throw in a different motor if it helps

[kevingrahambutler]

I had a very similar problem with my tenere 600, I ended up changing the second carb diaphragm and the needle as well, runs sweet now, the diaphragm looked ok but the rubber was very soft compared to the new one also the needle looked worn