XSively Frustrating

[DGXSER]

Thanks for the info on the Carb body. While I have not been around the biek when it was dead cold, I did pull the carbs off, and do a miny cleaning of them. Mostly looking for something big like a jet sitting in the float bowl or something like that. Point being, the carb bodies were stone cold, and the engine was not overly warm when I put the carbs back in, acted no different from the moment it was started and took off for a maiden voyage. But, I will certainly give the carbs a good lookin over in much more detail if the coils are not the problem.

[ExcessiveBiker]

WMarshy, cracks

WMarshy,
Where was the crack located on the carb body? I have had this problem for a while now, but lately the cleanup rpm has moved from 2500 up to 3500. This makes it much harder to deal with in traffic, which is every day.
It sounds like a lean condition, the way it backfires though intake. Just before it cleans up, it sounds and feels more like an over rich condition.
This bike ran pretty much error free for 50,000 mi, until this low speed bucking problem started. It would always idle (still does, hot or cold) and pull skipless from 1500 rpm. I pulled and twisted the pickup wires, to no effect. Gas mileage has actually picked up from 1 - 2 mpg, since all this started. Plugs are gray, as they have always run. Let me know if y'all have any more ideas about this nagging problem.

thanks,
ExcessiveBiker

[Yard Dogg]

If you think it could be sucking air, you can use a propane bottle and tip. Just turn it on and move it around the carbs slowly until you hear the idle rev. Then you can zero in on it. No need to crank the bottle up too much.

[DGXSER]

SUCCESS!!! WOOHOOO!!!

We started off installing my 78-79 carbs on his bike. Seemed a little better, but not enough to say we found the problem.

So, we started pulling off his coils. They were the Green Mikes XS coils. Tested them by taking ohm readings, both coils passed. About 3.5 ohm on the low side, 16.5k on th high side. Well, the harness wiring on the 80 coils must be alot different than the 81 model. I got a set of VF1000 coils off ebay for cheap, had them prewired to put on the bike. Well, the best laid plans of mice and men....I had a number of wiring connector issues to overcome.

So I changed the connectors on the coil wires to match what was on the bike. Pulled off the plug wire covers from the Mikes coils....again, not the same setup. Sooo...I pulled the plug wires off of my bike to put on his (I have the VF1000 coils on my bike). Started the bike up and knew it was much better. Took it out for a short ride, no doubt we had success!!!!

Now I know all you smart folks out there are thinking the same thing I was, three things were changed at once, coils, wires, and plug caps. Which was the fix?? So, at this point I decided to dismantle the plug wires from the Mikes coils and set them up to go in the VF1000 coils. Made that switch, put the bike back together and .........Fired rght up, runs like a champ!!!

So, if you find a mid range miss that seems intermitent, and you can't trace it to a single cylinder. The coils could be an option.

As to the Mikes XS Green coils, I know that the black coils seemed like they failed pretty quickly and there was a big move to the Green coils. Well, these had about 5,400 miles on them. Not alot of miles in my opinion.

[BA80]

Glad you found the problem but I still don't understand why the vacuum loss you described.

[DGXSER]

My theory on the vacuum loss ( a blip of all four vacuum dropping out) was that the cylinders were getting fouled with fuel from weak spark. Strong enough to let the bike idle, just not enough to produce power, or fully burn the mixture.

Not sure I can explain it any different than that either. But I know for certain it runs like a new bike with those VF coils as opposed to the Mikes coils that were in it.

[BA80]

So, since you've got it figured out does that mean your coming to the Iron Horse?

[TopCatGr58]

Chalk up another VICTIM of the Green MikesXS coils!

Hey DGXser,

Glad you found the problem, sorry it was the relatively new MikesXS Green coils, but we had a few hints of them recently, and now it's starting to show up more. Just want to make a mental note of this, may also find the Thread I started to add this one to the list.

T.C.

[STEPPENWOLF]

They looked pretty when new..




Low end miss started after about 4000 miles.

[BA80]

They looked pretty when new..

So did my last 2 wives.

[James England]

Is it possible that this is an electrical problem, I wonder? I did have an irritating low rev miss, always when going round a left hand bend....... when I fitted green Dyna coils and removed the ballast resistor, it disappeared forever....

Mmmm.....10 points to me, I reckon

[James England]

All good suggestions James but the only one there I see that could possibly cause loss of vacuum is diaphragms. I do agree that it could be a combination of malfunctions though.

Tell you what Greg, just give me your 10 points from the last correct diagnosis you made.,....

Now I win one of my own wheel bearings!

[BA80]

Tell you what Greg, just give me your 10 points from the last correct diagnosis you made.,....

Done.....

[DGXSER]

Greg, as to the wives...well...Those Mikes Coils did not require an XSive amount of adult beverages for them to look pretty at first.

James, I'll award you 5 points, the other 5 go to Biker Phil. Since you were suggesting to upgrade to high output coils, which were already installed. Phil hit the nail on the head with the Mikes green coils going bad.

But you can still have one of your left wheel bearings as a prize, just in case it will fit your XJR since your still XSless.

[James England]

But you can still have one of your left wheel bearings as a prize, just in case it will fit your XJR since your still XSless.

Damn! You reminded me. I have the chance of a 1977 UK spec XS1100. It's running and legal and looks OK but... it's non-standard in many ways and I'd want to put it back to OEM spec or thereabouts..... lowest price is $2,400.

It's getting to be the same old problem over here... the XS11's are up for sale at money which does not reflect their condition. I want them as a classic bike restoration.... which means that they always need a lot spending on them, regardless of how reliable or roadworthy they are. So, sellers are offering them for sale as, and priced as, 'classic' bikes but, in fact they are just old, big, powerful motorbikes, non-standard, bits missing, messed around with etc. IMO they only become classic bikes when restored to OEM type condition. So, if all that's up for grabs is a big powerful motorbioke, then there are plenty of more modern, faster and cheaper ones about. See what I mean?

I looked at one recently and the owner was waxing eloquently about how it's a "fast appreciating classic". Nope..... it's an old XS1100 with a knackered seat, non-OEM fenders, indicators, rear light, headlamp brackets, rear shockls. Missing lift handle. Non-OEM exhaust. Badges all tatty. Needs respray and new decals.etc etc etc. Probably $3,500 of parts/work needed. After doing all that lot (and paying for it) then it's a classic but not "fast-appreciating".

The above is why I gnash my teeth in frustration and envy when I read here about the amazingly low prices you pay in the US!

So, yes, I'm still XSless at the moment (thanks for rubbing it in....)...... but.... to alleviate my withdrawal symptoms, I do have the XJR1300 for some torquey, mind-blowingly fast performance. Mine's a mere 115 BHP, 148 mph, mildly tweaked one that will spin the rear wheel on a dry road and wheelie at 80 mph........ people over here are getting some amazing figures out of them.......... but..... I still miss my XS11!