1998 Steamer, Keihin carbs all messed up +fuel in oil.

[Persson]

Any smell of acetone in there? I have seen rubber do that when exposed to acetone. E-85would more likely just dry out the seals etc. Pissed any body off lately?  

That is what is so strange, there is no smell of anything unusual. No acetone , no burnt rubber or soot, no nothing really.
-Actually it does not even smell of gasoline...

[Mustang]

My bike has been running funny. Jerking and sputtering, uneven idle and backfires sometimes. In short, not well at all.

based on this info My theory is that the intake valves on #3 are at zero clearance , possibly other cylinders as well . zero clearance on intakes will cause backfiring thru the carbs .

It backfired and the fuel caught fire and everything went south from there .
once the fire started you had a needle valve stick open or melted a float which let the crankcase fill with gas

[Persson]

My bike has been running funny. Jerking and sputtering, uneven idle and backfires sometimes. In short, not well at all.

based on this info My theory is that the intake valves on #3 are at zero clearance , possibly other cylinders as well . zero clearance on intakes will cause backfiring thru the carbs .

It backfired and the fuel caught fire and everything went south from there .
once the fire started you had a needle valve stick open or melted a float which let the crankcase fill with gas

That is a good theory, and I will see what I can do to find out exactly what has happened.

Some short background info on the bike:

1998 Steamer Keihin equipped, with ca 40000kms on the meter.
I bought it last year from this chap who lived roughly 500kms from me.
Went down there and found it to be in better condition than expected, so I bought it. (It was/is really in excellent condition.)
However he had not used it for quite some time, only a couple of times per year, so it needed some TLC.
On the way home it ran fine the first hour or so, but later I noticed the engine started to run a bit jerky on low revs.
Nothing bad, only annoying.

Back home I registred here and got the tip about possibly poor performing coils. So I fiddeled with that, tested the bike, fiddeled some more, and so on, but never got the engine to run smooth all over the register.

I ran out of time and it became winter, so I put her away for the season.When I got back to it this season, I noticed that all 6 of the rubber boots connecting the carbs were all dry and cracked straight through at some places.
The airfilter needed to be replaced as well.

So I replaced all those parts, filter and rubber boots and at the same time cleaned out the floatbowls, visually inspected and cleaned the carbs.
Then put it all back together again.

--> And it´s probably somewhere here that I messed things up.

It all went back nice and smooth, and I took it for a test drive.
Performance was good, started up right away just as always, but with just a hint of "pofpof" when letting back on the gashandle. But no major.

Then suddenly it started to loose power, jerking more and more, and even stalled and died on me at an intersection.
So I headed back home and put it in the garage with no time to deal with that at the time.
When I started it up later that week, it started up right away, but with a heavy cough, spluttering and sounding awful. I tried a little twist on the gashandle, but it was jammed shut.
It was at that time I took it apart and found this rubber-boot havoc...


So I agree, the valves could be tight and probably need to be checked anyways.
But when it ran fine, it ran fine..
And I haven´t put more than 100km´s since then in test-runs. Not even that even.

Here is my reflection about it all:
-My guess now is that there was never any problems with the coils in the first time.
It was those cracked rubber boots and totally that caused the bike to jerk on low revs, and I messed things up with the floater needle causing the carb/s to freeflow and fill up the crankcase.
The gasoline dissolved the silicone around the airfilter, turning it into gooey silicone-chunks that then was sucked into the carbs in some kind of halfglue form, messing upp the moving parts in the carb and gluing them shut.
At some point here there was an ignition of the gasoline in one of the carbs , and that flame torched the rubber boots turning them into...crap?

And you are most likely right Mustang, something made the engine to backfire and a tight intake valve sounds like a possible culprit.

[Persson]

BTW,

Who was it here on the forum that made that excellent valve tool?

Anyone knows?

[Sin_Tiger]

:D  :D  :D

Well you could always experiment setting fire to the old ones just to satisfy your curiosity  

[Persson]

:D  :D  :D

Well you could always experiment setting fire to the old ones just to satisfy your curiosity  

 Not bad at all!
 

[rf9rider]

BTW,

Who was it here on the forum that made that excellent valve tool?

Anyone knows?

Mustang

http://www.knlcycle.com/

[Persson]

BTW,

Who was it here on the forum that made that excellent valve tool?

Anyone knows?

Mustang

http://www.knlcycle.com/

Haha! Of course, who else? :D  :D  :D
Thanx RF

...Mustang, You there?