fuel shutoff, replumbing, & individual filters

[kenkrieger]

Interesting finds

T.C.
I finally got to tearing down the bike after the N.C. Rally. I drilled out those plugs on my pilot screws to find none were adjusted anywhere near the same none were even close to the 1 1/4 turns suggested for a start, two of the four were backed out more than 4 turns. so here's a start for some of my rich running problems. Next I went into the bowls. I replaced the orings on the outside of the float needle sleeves, mine were flat, and leaking by. Thanks to your suggestion to check the mains ,which I never did previously,,,turns out they are all 117.5's,,,this bike did have the 4 in 1 and Indy filters before the previous owner put it back to stock to sell,,,well almost back to stock, so I had a swap for those 110's you gave me with me the whole time, hehe. The Jet Needles were in the right spot, so not all was out of whack. That I checked before,,,,just never read the mains,,,mind you this bike ran great for more than a year and 16k miles like this,,,albiet a bit rich (lol just a bit) down here in the low country and really showed the problems up there in the high country. I still have to get the quad seals from MR. Carb and I can get back on the road, after I get it to the Yeti's to use his Mercury gauges. Thanks for the suggestions.

[nashville_bill]

Although my bike was running ok, I decided to install one size larger main jets and pilot jets because the spark plugs were completely white and it was obviously lean when not completely warmed up. Well, now it is very rich with four sooty spark plugs. I can't belive that one size richer jets made this much difference. I am going to take out the 115s and reinstall my original 110 main jets and see if it helps. For now I will leave the 45 pilot jets in that replaced 42.5s. Wish me luck.

[TopCatGr58]

Jet Sizing, oops!

Hey there Bill,

I hate to tell you this, but it looks like you went up "2" sizes on your mains, they go by 2.5 increments, so the next step up from your 110's should have been 112.5 instead of 115 !?!?

Also, where are you floats, you can richen or lean things out a bit just by changing their height instead of changing jets!

Also, you state that the bike seemed lean when not warmed up?? From what I've read and been told, the bikes DO get leaner as they warm up, not richer! But going back to your 110 mains and keeping the 45 Pilots may be a good choice since Rob(carb guru) showed us at the clinic in NC that the Pilots contribute throughout the entire RPM range, and so you may get just enough boost from them without the drastic change of larger mains!?!? Good Luck, let us know how it goes!

[nashville_bill]

Runs much better now that I went back to the stock 110 mains. I think the 45 pilots are right. The floats test right on when using the tubing connected to the float bowl. Went for a 75 mile ride today and seamed to run very well even with the sooty black plugs I started with.

T.C. - loved the CD of NC - thanks again!

[Dennyz]

nashville_bill,

If the 110 are working well, dropping the pilots back to 42.5s, may provide crisper throttle responce in the low RPM transition.

[nashville_bill]

Dennyz,

The throttle responce is better with the larger 45s than with the 42.5s. The reason I was going to the trouble of changing the jets was that it was running a little too lean with the stock jets and the spark plugs were as white as new ones. I was afraid that the lean condition was going to melt something.

[Mike Hart]

I've resumed work on jetting my XJ, after being waaaaay too busy with non-mc things.

Met up with DennyZ, Jason, John Jones (CBR1000F) and Johnny Yukon (Bandit), went to visit Carolyne (XJ) in Port Angeles about 10 days ago, great to see folks and ride again.

Last installment saw my bike finally too rich with 142.5 mains and 50 pilots (vs 112.5/47.5 stock). I went back one size on the mains to 140's, and still am a bit rich, though DennyZ reported no rich smell/look from behind me. Got only 31mpg on the 130 mile trip, so I'll be reducing the size of the mains one size, then back to stock pilots, to see if I can get back to good mileage figures.

My Bandit went from 102.5/37.5 to 150/32.5, end result being a lot more hp and torque w/ gas mileage the same (abt 40mpg). (more power = less throttle opening at a given speed = same mpg)

I will be reducing the mains to get gas mileage up agn on XJ, and am considering reducing the pilot size. Denny has speculated that possibly the YICS system has something to do with the strange divergence from XS practice when it comes to rejetting the XJ. Since the pilots meter the mains, it may well be that a reduction in pilot size is called for a la Bandit.

I'm sure I'll get dialed in over the next month or so, and we'll finally have definite figures for how to rejet an XJ for individual filters and good power and mileage

[ratbyk]

Hi Mike, back to the never ending thread are we. Not having a nice 1200 Bandit to fall back on I persevered with my 78E until I had a smile on my face. Ended up with:
Mains - 137.5
Pilots - 45
Air - 210
Needles - 5GZ6
Float level - 1 3/16
Although I had been running a fuel line set up like you. (Y Adapter putting both petcock/fuel lines through 1 filter therefore one 1/4 inch line to feed 4 carburetors) I changed that. Went to 2 seperate fuel lines through 2 seperate filters to feed 2 carbs not 4 through a small 1/4 inch line on gravity fed fuel.
I think the one 1/4 inch line was causing a lean condition at higher revs. It was not able to keep up to feeding 4 carbs.
After this change I went from a lean condition to slightly rich. I started lowering the float level until I had my smile.
Ken/Sooke
78E Ratbyk

[davidenorth]

Hi, I am still learning about my 1981 xs1100sh and want to go to your alternative shut off valve and have materials to do so. I am wondering if air box removal is required, or did it influence your bike running lean?

[ratbyk]

On mine, the whole time I was sorting the carbs out I had removed the air box. I was running the rubber ram tubes from the original air box with fine mesh stainless steel screens over the end. It made life so much easier to R&R the carbs all the time. Once I had the carbs sorted and was happy I reinstalled the air box. This was to get rid of the intake roar and to provide some protection from air born dirt. It did not affect the running of the bike at all plus stopped the ABD problem.
So far as going to a fuel shut off tap through a "Y" I would not recommend unless you increase fuel line size from 1/4 to 5/16 where it all comes together through one line. I truly believe this set up was giving me my lean condition at higher revs.
Ken/Sooke
78E Ratbyk

[Snow]

Just reading through the last few pages of this thread brought up a recurring question for me:

when you measure float height, do you leave the bowl gasket on and measure from that or do you take it out and measure from where it sat?

[ratbyk]

Gasket in place.
Ken/Sooke
78E Ratbyk

[Mike Hart]

Originally posted by ratbyk
[ Went to 2 seperate fuel lines through 2 seperate filters to feed 2 carbs not 4 through a small 1/4 inch line on gravity fed fuel.
I think the one 1/4 inch line was causing a lean condition at higher revs. It was not able to keep up to feeding 4 carbs.

Hi Ken! I wonder if it was the single filter that was restricting the flow, because in the very first post of this thread I see I flow-tested the 1/4" setup at the equivalent of 5 gallons in 32 minutes. I think even a Special would run at 120mph for a half an hour no problem

and David, that fuel plumbing I did is independent of the airbox vs individual filters issue.

[ratbyk]

Mike, who knows. The fuel filter I used may have been different than the one you used. (likely was) Mine may have been more restrictive than yours. Now that I'm using 2 all my problems seem to have been rectified.
Ride on!
Ken/Sooke
78E Ratbyk

[Pickman]

Mike and Ratbyk,

I'm considering (ok waiting for clearance from SWMBO) putting 4 EMGO clamp-ons onto my '81 XSLH. While I'm in there I am also going to be re-plumbing my fuel lines.

Can the two of you let us know which fuel filters you used in the single filter set-up? If it does come down to filter type, I'd like to know which is going to work best. Ratbyk, did you use the same filter type on the dual-filter rig?

Any point in the general direction of jets to buy would also be healpfull (mains, pilots, etc.).


TIA,
-Pickman