Carb bench synched, will run and idle slightly high

It's got POD filters, doesn't it? And open or non-stock pipes?

Stock jets, or the recommended "starting point" for your mods?

Did you dip or otherwise submerge the rack when cleaning the carbs?

Did you "break" the rack?

The answers to the above will begin to lead us to the solution.

Oh, and please change your sig. Around here we check our affiliations at the door; put your bike info in your sig, like the mods I just asked about, so we don't have to repeatedly ask. We care about your ride, not your politics.

 

I got it to run with the choke barely turned on. I adjusted the pilot screw out and it ran better. The it died and would not start again at all. It was backfiring a little bit but nothing major.

So I have broken the rack completely apart and I am soaking it in a strong degreaser right now.
will spray with carb clean in the morning and put it back together. I didnt see too much that would worry me in the case of dirtiness. the choke plungers had some rusty colored sludge on the tips and I cleaned that.

I then cleaned the plugs and made sure they were still getting spark and yet it still wouldnt crank. figured flooding right?? well turned off fuel and waited for the bowls to level out and still nothing.

OH YEAH. I did finally bow down and do a wet set as well and from the factory 17.5mm for dry set I was only 1/2mm off so I am happy and get a sense of security from the wet set verify yay...

here in the pics the jet I am pointing at is supposed to be a 40 from what I can tell but it says 375???help



are these sizes correct??

 

BOY, I wish you'd answered before you did that.

The reason I asked is that it's NOT a good idea to soak or submerge the carbs unless you plan to replace the throttle shaft seals. They're trapped in the carb bodies, and soaking or submerging the carbs can cause your cleaning solvent to get in there and attack them. You may have just set yourself up to HAVE TO replace them, sorry.

There is a complete breakdown of what jets are stock for which bike, along with recommended changes for various mods, in chacal's "XJ Forever, supporting vendor" forum; I think it's in "church of clean."

My only 750 reference is the Haynes which I don't trust.

 

well I thought of that and what I meant by soaking it is that I just sprayed it down real good and shook off the excess to let it self dry tonight to where I can spend more time cleaning tommorrow,. haha sorry about the miscommunication.

like I say I have always been more familiar with EFI and these "jets are new to me so is the 375 really 37.5. I am just about to go bald wondering why it wont run unless I hold the choke on and I didnt see anything too horribly dirty when i broke it apart and the pilot screw didnt change much from 1-1/2 turns out all the way to 4 turns out.

 

The passages in the carbs are TINY and those are some grubby carbs.

All of the jets need to come out and get cleaned, the emulsion tubes need to come out and be cleaned inside and out, etc. You weren't seeing any difference cranking on the pilot screws because the passages are plugged. Remove the pilot screws, their washers, springs and tiny o-rings, and get the passages cleaned out.

Read this and follow it: http://xjbikes.com/Forums/viewtopic/t=2908.html

Read this: http://xjbikes.com/Forums/viewtopic/t=14692.html for the answers to your jetting questions.

And SLOW DOWN. You can't do a less-than-100% thorough job here or you'll be doing it again and again until you DO IT RIGHT. Right now you're looking like a potential member of the "I've cleaned my carbs four times" club; there are a lot of members here.

 

"Right now you're looking like a potential member of the "I've cleaned my carbs four times" club; there are a lot of members here."


hahahaha good copy.

 

<----- proud member of the "I've cleaned my carbs four times" club... if only I'd read more of these forums first!

 

When the complaint includes "Needs Choke To Run" the Carbs aren't delivering Fuel in the manner that they should.

Generally, that means:
The Pilot Fuel Jet ... It's Passage ... Including the Pilot AIR Jet and the Pilot Mixture Screw's Fuel Passages need to be Flushed and Purged.

The Main NOZZLE (a.k.a) Emulsion Tube needs to be extracted and thoroughly cleaned.
The Outside Diameter
Inside Diameter
Every one of the AIR Holes drilled through the Nozzle ... Cleaned.

The Passage between the Main AIR Jet and Nozzle Feed ... Flushed and Purged.

These steps often get neglected and make all the time you spend cleaning the Carbs unfinished business affecting performance.

 

Well I have gone in meticulous detail to clean and purge all passages and orifices. I have notice that these carbs have been worked on before and I soooo hope that the PO did not soak these carbs. But who knows right. The only thing I did not do was to remove the butterflies for fear of damaging something.

So, having said that, I can now crank it waaaay more easily. I had to start it with choke until it warmed up. Now It will run with the choke being "barely" on...(sorry fuel enrichment circuit, lol)

Once I get that far, I can start to screw the large idle screw from not touching at all until I can hear the engine revving higher. The motor will then run without the "choke but it is screaming....as I begin to screw the large idle screw back out it lowers the rpms down a little but then I hit the sweet spot...It will either scream or just die. AAARGH

I am happy to know that I finally removed my head from the dark spot and broke the rack and took it to church. So now what???

P.S. the pilot screw is set to two 2 turns out and that is the best spot to make it "sound right.

when the petcock is turned to "PRI it rolls out of the tank\
when set to "RES it trickles out
the filter is clean.

 

Umm I just got it to run without:choke and when it would be close to dying I would keep it alive with the throttle. I notice something possibly horrendous though. As I would throttle it I could see the shaft the butterflies are on spinning correctly but I did notice a little bit of wiggle in it. SO should this be able to happen or should it be completely still other than the spinning??? I may have figured it out.

 

Spinning?
They shouldn't move.

See if you're missing a Sync Screw or Spring.

 

I may be talking about something different then...The butterfly valves are screwed onto this shaft. I couldnt see how it would operate without spinning.





I am A+ positive it went back together quite right. So maybe I am thinking that this 1mm or so of wiggle is telling me that I need to replace those seals.

Ill be darned if I can find a brake cable from the handlebars to M/C

 

Spining as in round and round as it runs or turning to open the butterfly? Are the C clips on the end of the shaft?

Did you PM chacal about your cable?

 

Ah, I see, No it just spins back and forth as the valves open and close. It does however seem to have some endplay and that worries me. I can make it wiggle with my fingernail and it is wobbly while running. Better safe than sorry and a process of elimination tells me to just buy the seals from chacal.

 

Get a real JIS screwdriver while you're at it; makes getting the butterfly screws out SO much easier.

The phillips screws on these bikes aren't "true" phillips screws; they're Japanese Industrial Standard (JIS) cross-points.

While a standard phillips can be modified to better fit (by knocking the point off the tip) only a real JIS screwdriver truly fits.

Oh, and I agree that if the throttle shafts are "bouncing around" in relation to the carbs when the engine's running, you probably DO need throttle shaft seals.

How many times will this make now? Club membership looming... (sorry, couldn't resist.)

 

haha rub it in.

 

Hey, man-- anyone with a running XJ has probably been there, done that. Don't say we didn't warn you about 4 pages back...

Like I've said previously; if you take ANY shortcuts, the bike WILL make you go back and do it anyway. The only way to do something only once with one of these bikes is to do it 100% right the first time.

 

just pm'ed chacal for some seals and crush washers for the brakes. gotta wait on some funds before the 900 dollar project is done

 

In case you are going to see if you CAN get it running, ...

Pilot Mixture Screws have gone through a good deal of Troubleshooting.
-2.5 Too Lean.
2-1/2 Turns out. Obsolete Factory Preset.
2-3/4 Turns out. 1st corrective enrichment.
3.00 Turns out. Median adjustment for ColorTuned Mixtures.
+3 to 3.5 Colortuned Mixture with Supplemental Richness.
+3.5 until the Screw falls-out = Wide open. Rejet.

 

I appreciate that heads up. Seems to me I would need a jet change either way because it has a 4 into 1 exhaust and the dreaded pods with stocker bits for the jets. But I would have banged my head against a wall looking for that info Thanks

 

sorry for the wait. The shaft seals really helped. I can rev it up and down really nicely now and it will run with choke off after it warms up but It will still die so I need to keep blipping the throttle.
Next guess is the float valves are worn out even though they dont look the sort.
either that or the petcock is dumping fuel in there like no ones business or a combo of the both.

Glad to be in the club..teehee
At least I now will have a working knowledge of the induction system on this beast.

 

The petcock can pretty much do whatever it wants if the FLOAT VALVES are working correctly. Once everything is functioning correctly, the bike should run just fine even if the petcock is on PRI.

Sounds like a combination of float levels and sync at this point.

When you wet-set the floats (individually, of course) using fuel and the clear tube method, you'll be able to easily diagnose any "fuel dumping" issues. If you short-cut this process, go back and do it carefully.

Once you do your running vacuum sync, with the YICS blocked, you should get your idle back.