"A cry in the wilderness"

[prometheus578]

I'm trying to quickly finish up an "E" model that I bought two months ago. The plan is to trailer out to Colorado an XS850 for my brother and preposition the "E" out there for my future use. Have replaced the tires, all wheel bearings and steering bearings, forkseals, etc, on both bikes. Just need to do a quick valves adjust and snake in a new cam chain on the "E"(45,000 miles)
My question for y'all at higher altitudes is: What size main jets are you running? Reason for askin' is... every trip I make to Denver, I always end up foulin' me plugs; usually by the time I hit mid-Utah, so input from ae7f would be helpful, too.
My "F" had, as does this "E", 137.5 mains and MAC exhaust. Airbox is stock.
Any thoughts or experiences?
('course, at the rate things are goin' fer me, I may end up just crammin' the 850 in the back of my Blazer, and save takin' the 1100 out there for my end of summer trip)

[CWilliamson]

I live at 7028ft

According to my dad's GPS (Colorado Springs) and I think that my 79sf has stock jets (previous owners weren't the type to change them). I'll take a look since the carbs are torn down and let you know.

Clark

[trbig]

Just me personally... but I would rather be running to rich than to be running too lean in the low spots. Also... I have stock airbox still like you. Seems like it would be MUCH easier to just replace the fouled plugs than remove the carbs and replace jets.
Maybe even get the K&N style airfilters for just the trip... that's supposed to be about 2 jet sizes lean just doing that isn't it?
Just throwin' suggestions out here.. Have a safe trip. I grew up in the Graham area in Washington.... I would LOVE to come back there and do some riding up around Mt Rainier. It's my 20 year reunion this year.... might think about actually doing that... hmmmm.

Tod

[portero72]

FYI-i have a 79f with a mac exhaust. after it went on i took it to the local race shop and put it on the dyno w/ the EGA(gas sniffer). turns out the mac system made it run waaay rich, and had to go DOWN 2 main jet sizes and drop the needles one groove(runs like a champ!). i'm in austin, so if you're in a higher altitude, it may be even worse for you. my .02$

[motoman]

Being a native here in Colo., where your gonna be riding for the most part, and in Utah, 132mains there abouts and If you don't like a little stumble off idle back out mix screws 1/4 turn for the higher elevations above 7-10,000ft. Denver your around 5,000 for the most part, Here in Grand Junction, bout 4,700....into Utah bout 5,500ft. Hope that's of some help.

[pggg]

Advance the timing 5 deg for altitude.

[prometheus578]

"Rich beyond the dreams of avarice."

That's funny, Potero. Not that I've been keeping great notes on how the bike is performin', but I seem to 'member that when I put the pipes on a few years ago, everything was fine. Till last summer, and then it started running lean. I'm actually UP two jet sizes right now, and just startin' to get some color. Don't know, nor care, as I love to tinker.
Float bowl screws have all been replaced with allen-head cap screws, so can pop bowls whenever I care to. Always travel with a different set of jets and and spare float needles. Have been seen tinkering, (and tinkling)along side the road on many occasions.

[portero72]

ahhh, the joys of old bikes....

[prometheus578]

"Ode to Joy"

ahhh, the joys of old bikes....

If you can't fix them... why have them?

Hhmmm... My meaning is... a bike that you can fix yourself is a joy forever.

[apolloant]

Carbs/jets

For Prometheus.. Can you change the jets with the carbs on the bike? Is it just a question of getting a screwdriver in there? And, does any one know where I can get stock jets. I've got a Mac 4-2 with a k&n and no idea whats in the carbs. Seems a little rich.

[TopCatGr58]

Feeling snubbed!

Hey there ApolloAnt,

I'm not Prom, but here's some info for you, but you can wait for Prom to drop in, about once every few days now, since he has a woman to keep him occupied along with the weather starting to turn nicer, so he'll be getting more bike mech work at his work place!

Here's a photo showing the inside view of the 79carbs.


The bigger screw head closest to the float is the MAIN jet, and isn't too hard to get to and remove. The other under the distance screw head/pilot tower cap is the pilot screw, and it has a very small opening to fit a screwdriver in there. Also, they can be pretty well stuck in there IF they haven't been removed in a long time. They are made of brass, so the it's not too hard to break off the slots in the pilot jets EVEN WITH a good fitting screwsdriver tip!

You say your bike seems a little rich, how so?? Are your plugs coated with flaky black soot? Or are you talking about how the throttle responds? Trouble with low rpms, or bogging down when trying to open up the throttle for accelerating?

The jetting guide would recommend about 2-3 sizes up from stock with your mods, stock being 137.5, going up to 142.5 or 145 mains would probably what you would want to change to. You can find jets at BikeBandit, MikesXS. You might not need to change your pilots, you might be able to get good results by just turning the pilot screws out a turn or so, this makes it more rich, but would depend on what your symptoms are as to what you would want to change !
T.C.

[apolloant]

I haven't fixed the wires on the pick-up yet, but I pull on em and it doesn't really change the behavior of the motor. The plugs are BLACK.... I have soot coming out of the slip joint on the headers when it's running. Give it gas, and it pops and putters. Advance it and it mellows out, but i think the advance is too much, 2/3 to the end of the adjustment. I can't test ride it cuz we got snow last night, ice this morning. I just needed a jet rec. and to know if I'll have to take the carbs off the bike. Carbs freak me out a bit, too touchy. p.s. Local mech. here told me that '79's didn't come with cdi, just points, so it must be a refit. I decided to avoid him from now on.

[TopCatGr58]

Carb hell, continued!

Hey there again Apollo,

Just reread your other post. Don't let the carbs scare you, they aren't as hard to work on as people think. Your previous post said that the PO had the carbs worked on and rejetted, and then was able to put 3k miles on it before it started to act up! The bike only has 12K miles, but still has 25 years!

The black soot is definitely too rich, but it could also be a matter of not getting enough air, vs. the jets being too big! First check the snorkel to make sure it's not kinked, or rodents have made a nest in it! Also recommend taking the air box off. Then take your finger and slide up the vacuum slide to see if it moves easily up and down! Next, push up the slide, and then put your finger/thumb over the arced large port on the top of the carb inlet bell, make a good seal, and see if the slide slides back down or stays up, or at least slides down slowly. IF it drops fairly quickly with your finger over the port, then it's probably got holes in the rubber diaphragm that'll need to be fixed.

IF the slides are sticking and don't slide up easily, then that can also contribute to the rich condition, as well as holes in the vacuum slides, which would prevent them from sliding up under the proper vacuum load.

An exhaust leak usually produces a leaner condition, so even though you'll need to fix it, I don't think it's contributing much to your problem. Do some more investigating, and then post back to your OTHER THREAD, so we can keep track of what you've found, done, etc.!
T.C.

[Winterhawk]

I think I'll let the Mechanic Apollo met tune mine also.
(Clean and Gap points, set timing, ect.) I can't find them.
I think he's right about no CDI.

[John]

Yeah, take it in for a tune up, and ask to see the old parts, and ask to be shown where they are located on the engine. Then when he thinks you are a total dork, call him out and point out just how crooked his shop is and report hm to the BBB.