Anyone want a nice XS825?

[Crazcnuk]

Well, I have anice smooth running 825.

#1 cylinder just won't run. I took the carbs off again, and rechecked them for the 4th or 5th time.

The carb is getting fuel (flow tested) the spark plug sparks steadily, but the cylinder only pops, about once every 2 or 3 secs, back through the intake.

If I pull the vacuum cap off it stops the popping, and does nothing. When I put the cap back on it starts popping again. If I pull the cap off quickly, to catch one of the pops, it spits flame out the vacuum nipple.

I changed the manifold and now it's blowing right through the 'new' one.

Using propane shows no change in engine rpm (to check for vacuum leak).

I tried putting a few drops of gas through the vacuum nipple, no change.

At idle, the #1 pipe will get hot after about 5 minutes, but on the road it's stone cold.

Ideas?

[bikerphil]

Is the compression good? Maybe a leaky intake valve.

[Crazcnuk]

I was wondering if this is what happens if you never check your valve clearances?

The space would eventually tighten up until one of the valves doesn't close anymore.

[DGXSER]

Sounds an awful lot like what we saw when working on another members bike that ended up having a bent valve. Could just as easily be the clearance issue holding it open.

[Crazcnuk]

And it ran? Any I've seen with bent valves had several, not just one.

[DGXSER]

Yes, it did run, and it only had one bent valve. Typically they get bent from timing going out, but if you try to put the cams on out of time, you might only get one perhaps. All I know for sure is it ran like crap, we checked compression and that cylinder was very low, so we pulled the head off and found one bent valve.

Not sure how this happened really. But it was a replacement engine bought form a so called mechanic friend of his and was a "good" engine. I learned alot of things that can be wrong with a "good" engine going through that one.

[dbeardslee]

XS825? Is that a Canadian variant? If it has the three coil setup like the XS850's, you might try swapping coils on the #1 cylinder just to verify it's not ignition related. I've seen bad coils do some pretty weird stuff, including backfiring through the carbs, even though they appear to test OK. If the compression check looks OK, you might try it. JAT

[Crazcnuk]

This one doesn't run like crap. In fact, at idle it purrs perfectly, except for what sounds like a lean 'pop' every few seconds.

Around town you would barely notice the one missing cylinder, it's not until you are curising at highway speeds and you try a roll-on pass that you really notice the missing power.

That and, when you get home, #1 pipe is cold. You can freak other bikers out by reacing over and grabbing the pipe with your band.

XS825 = XS1100 - 1 cylinder (1100/4 =275 x3=825!)

[Geezer]

That really sounds like an ignition problem. The first suspect is connections and after that a coil (that is if you've already put in new plugs.)

Geezer

[dbeardslee]

XS825 = XS1100 - 1 cylinder (1100/4 =275 x3=825!)

Now it makes sense .

[Crazcnuk]

"The first suspect is connections and after that a coil (that is if you've already put in new plugs.)"

I would agree, if #4 was also having issues. it can't be strictly a coil output issue or connections INTO the coil problem,or any other part of the ignition before the coil or I would have 2 cyls not firing.

I changed all the sparkplugs and the sparkplug boots, but may have a weak spark plug wire to #1. I can easily check this by swapping the wires between the two cylinders that fire off the same coil.

[XJOK2PLAY]

Craz,
My first thought was right in line w/ the rest of these guys... it sure sounds like an intake valve's not sealing.

-Too funny Dbeardslee....
It took me just long enough to grab the 'ole calculator and figure 75% of 1100 to get it.... and felt kinda dense having to do that.... I shoulda been able to at least done THAT math in my head!!! LOL Why did I have to have another birthday this week? I can't afford to lose many more brain cells...

Thanks for making me feel better about myself... ya didn't have to do that just for me, ya know...

Good one, Craz... hope you get 'er figured out soon.
+1 on compression check. Figure it'll be enlightening.
If not... does that mean you'll be taking 25% off your asking price?
Take it easy.
Bob

[Geezer]

"The first suspect is connections and after that a coil (that is if you've already put in new plugs.)"

I would agree, if #4 was also having issues. it can't be strictly a coil output issue or connections INTO the coil problem,or any other part of the ignition before the coil or I would have 2 cyls not firing.

I changed all the sparkplugs and the sparkplug boots, but may have a weak spark plug wire to #1. I can easily check this by swapping the wires between the two cylinders that fire off the same coil.

I've jumped into this thread late, have you done a compression or leak down test?

Tony

[Crazcnuk]

Not yet, that will be next, as well as swapping the #1 and 4 spark plug leads to eliminate the high tension wire.

The weather has been so miserable here lately, and with no garage, it's been very depressing having to tinker in the rain.

The only thing that makes it seem, to me, like not an open valve, is that I assume an open intake valve would really explode through the carb, and it should do it very steadily (every other revolution?) . This one pops every few seconds, like every 20-40 revolutions.

[Geezer]

I understand about the weather. My garage is full with my business and I only have enough room to bring a bike in when I'm not doing much like over the winter. It feels like it's been raining here forever and I'm going nuts for lack of a ride or to finish a couple projects on my bike.

Geezer