Carb issues and rev issues

So i am at the point were my bike starts and idles fine. When i give her some throttle she stalls out. I am guessing cause she is too lean. So i plan on putting in a jet kit this week.

When i was looking for leaks in the engine to carb boots, i sprayed some starter fluid to see if there was any jumps in revs. I accidentally sprayed the bushing/clip that sticks out of the left side of the carbs for the buttleflys and the engine spiked. I also tried putting my finger over it and it does effects the idle. Is this a sign i need to change the o-rings? or is this typical behavior? I already did a partial rebuild minus the o-rings and everything was fine with the carbs back in June. I am guess from being off the bike since then things might have dried out.

I currently have pods and a modified exhaust. Stock headers and collector but with a 3 inch harley slash cut mufflers with no baffle.

I also noticed white smoke coming out of the exhaust on 3&4. The valve shims were just done and a compression test had everything in the 150 - 160 range.

https://www.flickr.com/photos/tbran/22608491863/in/dateposted-public/

 

Try spraying it on the right side (#4 carb) throttle shaft end, bet you it spikes there also.
That would affirm that you need to take that rack apart and replace the throttle shaft seals.

Those seals are most likely 33 years old and are very tired.

 

yup that means you need the throttle shaft seals try using an unlit propane torch instead of starting fluid.
if you get a jet kit DO NOT DRILL THE CARBS

here is a few links for you to read
this link tells in detail how to tune the carbs
http://www.zrxoa.org/webpages/techinfo/carb/carbtuning.html


this one covers rejetting basics
The Information Overload Hour


this one tells how they work
THE SECRET LIFE OF CARBURETORS

IN THE CHURCH OF CLEAN

http://www.xj4ever.com/inside your carbs.pdf

TALKIN' TECH: Various thoughts on various issues

for parts and more info

http://www.xjbikes.com/forums/forums/xj4ever-supporting-vendor.23/

 

I did the whole propane trick and i can never detect a leak. Which is why I used the starter fluid.

The stage 3 sigma kit i have is asking to drill out 2 holes on the plungers to help it lift. Its been awhile since i saw the bottom of the plungers but i don't remember seeing holes there anyway.i was just going to shim the needle and change out the jets.

 

Once you replace the throttle shaft seals you'll find that you won't need the jet kit (unless you are making modifications to the engine or intake).

 

And that would solve the bike stalling out when i hit the throttle? I have pods on it and a baffle less mufflers.

I always thought the bike would still run with the pods on it just crappy. The other major concern for me is the 3 & 4 headers are running super hot and white smoke is coming out. I doesn't look blue and i dont smell oil burning. so i am at a loss

 

Did you vacuum sync? If so, what equipment did you use?

 

He has a vacuum leak (as proven by spraying carb cleaner at the throttle shaft seals).

He also has pods (which was not mentioned prieviously in this thread).

Sybe,

After you replace the throttle shaft seals (this is not an optional exercise. They have to be replaced or you will always be dangerously lean no matter what jets you have in it) you will want to use that jet kit afterall. In the meantime STOP RUNNING THE ENGINE!!!! The factory jetting is somehat lean to begin with; then you switched to pods, leaning the mixture further; plus you have a vacuum leak which is making it even more lean. Keep running it like that and you will hole a piston (if you don't burn a valve first).

 

Read ya loud and clear. I already ordered the necessary o-rings from Len and they are on their way here. I plan on installing the jet kit when i do the o-rings. I'll keep you guys posted how everything goes.

She does sound sexy though! Link in the first post.

 

Have any of you used an unlit map gas torch for checking vacuum leaks? (small yellow tank... rather than black or blue). I was using it to check for leaks and had absolutely no spike in idle. Now I'm wondering if only propane will do the job to give the desired results if indeed there is a breach.

 

MAPP gas will work as it burns just as easily as propane. I've found that if the throttle shaft seals are leaking you won't necessaraly find the leaks using flamible gasses.

Carb cleaner seems to work best, and the engine needs to be at operating temperature for the leaks to show up. The throttle shaft bores expand at a different rate from the throttle shafts, and often it's not until the bores are thoroughly warm that the leaks show up.

Carb clenaer is also easier to direct into specific areas.

 

Thank You!

And now for a more important question... How do you quote from further up in the post with the "k-moe said" designation? I used the QUOTE tag in other posts, but it doesn't give the name of the original author... Sorry for the dumb "blogs for idiots" question... heh...

 

Click the Reply text in the lower right hand corner of the post that you wish to quote.

The real savvy people can quote multiple posts in one. . . I haven't figured that out yet.

 

Hit reply. Copy, paste, repeat as needed.

 

Or just highlight the text you wish to quote (left click and drag) and click the reply annotated in the black as noted in this screenshot below:


You then get this from the above, and you can do it multiple times from multiple members within that post:

 

The needle jet is 112 and the pilot jet is 43 Dare i say it... my bike might be a Canadian!
I noticed these sizes when i did a partial rebuild.



Would explain

 

does your vin contain 5N9 after the JYA 1982-83 XJ650 Maxim Canada: 5N9
if po put pods on could be it was rejeted

 

the jet marked 112 is the main jet, the needle jet is under it, the needle jet needle is the pointy thing that goes up and down with the slide.
don't buy the wrong part

 

The needle jet is also called the emulsion tube.
Honesty (IIRC) the only thing different carb/ engine wise between Canadian and U.S. XJ's is the jetting. You shouldn't need to rejet; it'll just run richer than a U.S. bike is all.

 

pic and something about 1000 words

 

JYA5N8... That was a close one! ;P

I miss spoke before. I got the right jets and they are already on. I went with the 130 for the main and 45 for the pilot.

Putting on the new seals for the carbs now, can i lube them up with white lithium grease? or should i avoid it?

 

someone's going to have to show me a manufacturer site that calls a needle jet a emulsion tube
why would a "emulsion tube" needle jet be non replaceable

 

Emulsion tube is the fancy term and they are replaceable. Hell i got an extra set of 4 sitting next to me.

I also just want to add the jet is not the emulsion tube. Its whats on the other end of it.

 

^what he said. In addition the emulsion tube gets it's name from the act of blending air with the fuel as it travels up from the main jet; it makes an emulsion (think foamy egg whites). Early SU carbs (the fellas that invented CV carbs) had the main jet and emulsion tube machined as one piece, which is where/who the term needle jet came from IIRC.