1989 XT600 2KF Struggling to run smoothly
 

Heya!

I have recently bought a 1989 XT600 2KF with the purpose of doing a long trip to central Asia in about 20 months. I have some experience working on my other bike (1998 Suzuki GSX600F), but nothing major, so I hoped preparing the bike for the journey would also allow me to learn the ins and outs of this bike.

The bike is very low miles (+-22k kms), and had sat at the owner's house for a long time before the guy I bought it from purchased it, so I expected having to changes lines, gaskets, etc.. The guy I bought it from says the oil + oil filter have been changed, the carburetor was cleaned in an ultrasound bath and the sparkplug was changed. The bike ran fine.

After purchasing the bike, on the ride home, I noticed some issues with the bike. When opening the throttle it would stutter and jerk, irrespective of speed.

I stopped after around 100km's, and took a break. The engine cooled off, and when I got on it again it started first kick, no problems. A few minutes later at a red light, the bike shut off the moment I opened the throttle, and wouldn't turn on again.

After managing to get the bike home in a van, I pulled out the carburetor and the spark plug. https://imgur.com/9Lqw3Q3

I rebuilt the main carb (following this video https://youtu.be/yq-Bj97Q1qs?si=rrK9-PKL9iv5NdPz)using a tourmax rebuild kit that came with some gaskets, o-rings and a new float needle +bushing it sits in. I cleaned out both carbs using compressed air and WD40.
https://imgur.com/5CTXMr8

https://imgur.com/sm8iTzh

I cleaned the rust as much as I could after fully disassembling it.

https://imgur.com/by2eEmr

The secondary carb membrane had a little pinch in it on the bottom left of the picture, so I straightened it out and cleaned it.

I noticed the jet at the bottom of the secondary carb in the video was tightened with a nut, while mine was a single flathead screw, that was STUCK. So I let it sit in WD40, but I couldn't get it out. I cleaned as much as I could from above and reassembled it (looking back now that might be the reason I have to do it again....). Stuck it back on the bike, and went for a short test ride, with no issues!

However, after about 5km the issue came back, with less violent jerking now and more sputtering. When riding at low rpm the bike does mostly fine, with some random sputtering, but when i open the throttle slowly it starts to have issues. When I go WOT it pulls through with no problems.

So before I pull the carburetor out again and start trying to figure out the issue myself, I thought I'd post here and see if there's any other things I should have done/checked while the carb is out. Also if there's any other general things I need to check with a bike like mine I'm all ears!

Paul

To start, I know VERY little about the XT600's, so maybe someone can come up with a magic fix, but here's the standard basics for any bike with this history.

The following is also based on your planned trip, where you want it all done RIGHT and not have to worry about it.
IF the carbs were cleaned in an ultrasonic bath - though I think it was either a very long time ago or very poorly - it's still looking very dirty and "gungy". Personally, I'd do a thorough clean with carb cleaner, NOT WD-40, it won't do much for you. THEN I'd toss it all in my Ultrasonic cleaner, then I'd give it all anther shot with with carb cleaner and compressed air, and reassemble with fresh gaskets and diaphragms, making sure to set the float level correctly by the manual, and the low speed mixture screw.

The linkage at the top of the carb is rusty - find some rust remover and clean it all up. Do it right, do it once.

While all that is cleaning / soaking, I'd set the valves.

Next, replace the spark plug - that one is well past it's replace date, and also looks very rich, which says carb issues. While you're there, check the compression, and also the ignition coil wire and plug cap, and all the grounds everywhere on the bike. (Why? Because if you don't do it now while it's easy in a nice workshop, it WILL bite you in the worst possible place.)

Finally follow with the correct procedure to synch and set up the carbs.
That should do it!

Thank you for the tips! Unfortunately I wont be able to do this in a nice workshop hahahaha, I have to work outside as I live in a big city with no garage space available (at a reasonable price).

I do need to go through everything thoroughly, as issues in the middle of nowhere does not sound fun :P.

Also that sparkplug has around 100km on it, so it must be really rich...

It's a nicer workshop than in the mud and rain and dark... :)
My first five years riding were all with the bike parked on a moderately busy street. :( I learned though.

If that plug only has 100km on it, yes, VERY rich - so the carbs are definitely not right. Go through the steps, do it right once. I learned THAT the hard way!

That is true hahahah

Thanks for the tips, I'll post here again whenever I have some updates!