Carburator bog on throttle

Hey all,

So I am stuck!! totally lost now and am not sure what else to do. 81 XJ650H. So I have rebuilt the carburetor. put in brand new needles, floats, filters. I have taken the bowls and ultrasonically cleaned them. check every port for flow through. I have done a bench synce. A wet set. I've checked the levels of the bowls to within 1-3mm as required. I've double-checked that the Main and Pilot are cleaned out and in the correct position and yes I know the book is wrong with the verbiage. The bike idles and starts up without question. The problem here is it bogs down and will die if I throttle it without the choke about all the way on. The only thing left I have to check now is to do a compression test on the cylinders. Any thoughts? other than breaking down and putting it in the shop I'm lost. Oh, also I have new rubber boots on as well. No air leak. I've checked for all that too. The bike will ride but only again with the choke on other than that she has full power.

Thanks

 

I’m had the same exact problem, when I took the carbs back apart (only 150 miles since rebuild and manual cleaning) I sprayed out the mixture screw port and lots of dirt and grime came out, I thought it got really dirty rather fast.. but it ran fine again after the clean

also the tiny hole in the float bowl NEEDS to be completely open, the one that slides over the brass needle

 

Thanks. Im gonna have to tear it back down I guess. It is possible it clogged up again. Nothing to loose at this point.

 

I was surprised, 2 weeks with ethanol fuel sitting in the carbs gummed them, I will only use non ethanol now

 

Yes non-ethanol fuel and inline fuel filter also a good ideal, recheck your wet set too that's where most of my issues ended up being you can read my past post for more info on that topic.

 

Thanks.

I'll check the wet set again. I've checked it everytime I've pulled the carbs off the bike. They have been pretty spot on but I have read that this is the very finicky spot and must be perfect. I've tried t keep all 4 within the 1-3mm range. I did notice the other day though I turned my petcock to prime and it didn't take long and fuel started to pour out the carbs while my bike was n the kickstand. Shouldnt the fuel stay contained even with Prime turned on.

Thanks

 

It should have, yes. The floats can get stuck "open", and sometimes can be freed up with a good whack from a 2x4. But if you're gonna open them up anyway to check the wet set, you might as well make sure those floats are moving freely.

 

It's the needles and float seat and valves not seating and need replacing.

 

Well the float bowl holes are completely clear. so its not that. I am going to check the fuel mixture screw holes I bet that it is clogged because everything else looks clean. Hope to do that tonight.

 

So I did some double checking as I was tearing my carbs down and I saw the my fuel jets were changed. They were 43 instead of 40 and also 112 and 122 instead of 110. pretty sure I found the problem. Will see soon.

 

Also as I was cleaning the carbs a very small o-ring popped out. No idea where it goes. Its like super small. Any ideas? ThNks

 

Mixture screw o ring.

 

Thanks. Ya I figured it out but wanted to be sure. Appreciate the response