82 XJ750 Maxim Idles and revs in neutral but no power

I have an 82 XJ750 Maxim that I got from a friend and I have been trying to get it running. I just rebuilt the carbs, new jets, seals, needles, and emulsion tubes. I tuned the bike so it idles and revs in neutral, but once i put it in gear it bogs down when I give it gas, and if I increase throttle slowly it will continue to run, but it has almost no power. Cant even ride it up a slight incline. Im new to working on bikes so any suggestions would be helpful. My guess is that the slides aren't opening up all the way with increased throttle. They seem to move somewhat easily if I push on them with a finger, but I'm relay not sure how to get those to move properly if that is the issue. Again I'm open to any suggestions, and thanks!

 

This could be a list of a lot of possibility issues, but my knee kick is did you wet set/sync the floats per the video on this site ?

 

maybe you have fuel jets in wrong position big jet is main jet and goes on emulsion tube.
reversed air jets
manual has the labeled incorrectly.

did the slides pass the klunk test?
chemicaly clean slides and polish the slide bore clean.

 

They do pass the clunk test now that i think about it. May not be the slides after all. I double checked when putting the fuel jets in. Will definitely check the air jets.

 

I did not wet set the floats. Im using the floats that were in the carbs when i got the bike and i haven't played with the float setting. That is something ill have to try out.

 

Do you have float drains on your carbs, if so put the bike on the center stand and measure the amount of fuel common out of each carb.
You can also do a wet sync check on the bike with some clear 1/4 tubing.
Lets see if your getting the correct amount of fuel for starters.
Did you watch the video on wet syncing the floats ?

 

You can only check them on the bike. You will need to remove the rack to actually adjust them.

It sounds to me like you're getting ahead of yourself.

IN ORDER:
Valve clearances in spec.
WET-SET float levels, accurate bench sync.
Running vacuum sync with YICS blocked.

Or fight with it until you do whatever you missed of the above.

 

Are all four cyls firing?

 

Check spark on all four plugs. I resurrected a 550 after 20 years. Carbs went thru. Upon starting it had no power also. Two plugs were not firing and turns out the coil pack was shot. The caps were also suspect at best with a lot of corrosion inside. There are small springs, a resistor and small copper washer inside the caps if u unscrew the part that clips on plug. After fixing the caps and coil it ran much better. Just minor carb tweaks needed.

Keith

 

I do have float drains on my carbs although one of the screws to open the drain is stripped, I did watch the video on dry/wet syncing and will get some clear tubing to do a wet sync before i take the carbs off again.

 

When idling it seems to only want to run on the middle two cylinders, especially when the engine is cold. Anything over 2000rpm and all 4 cylinders fire and bike runs very smooth with a small hesitation at ~9k. But still no power once its in gear.

 

Thanks Keith! I have another set of plugs gapped and ready to go in so ill check the spark on each cylinder when i go to change those out!

 

Put the new plugs in and the bike now idles on all 4 cylinders!!! Still no power under load though. I can rev the bike in neutral just fine, but when I put it in first, let the clutch out, and add throttle it bogs down and dies on me. Ran the bike and pulled the plugs to check mixture and the plugs are coffee brown so at least the mixture is in the ballpark.

 

All you can do with the carbs still on the bike is a very general wet-check of the float levels. Setting them will require having the rack off the bike.

Also, you're getting your terminology a bit conflated here. Wet-setting the floats is to ensure proper fuel levels. There are two types of "sync" required and they do not involve the floats. First is a mechanical "bench sync" performed while the rack is still off the bike. The next is a running vacuum sync, with YICS blocked.
YOU CANNOT DO A VACUUM SYNC if the valve clearances are not in spec.

All this fiddling about will be USELESS until you make sure the valves are in spec. The requirement won't go away by ignoring it, which is why that is the best place to start.

 

Well… Yes you can do a vacuum sync if the valves are not in spec…BUT it will be completely negated when you DO Get your valves in spec—-At which time you will get to do your vacuum sync all over again At which time you’ll wish that you had done your valve check first, The first time! LOL

If you sync your vacuum with valves that are out of spec, you are Simply doing a vacuum sync to an already compromised system. If any clearances are way way way out of spec, then you may not be able to even get a sync… In which case, like bigfitz said-you will need to get your valves back in-Spec before you can do anything. But yes, you should always get your valves in spec before doing your vacuum sync

 

Welcome to the site Drich !