bog on bottom - did it again! Arrgh!

OK - my 2001 426 has never had a bog on the bottom. I developed one a couple of weeks ago that wouldn't go away with fuel screw adjustments so I cleaned the carb. Wooohooo! It went away.

It came back on my last ride! Arrgh. I was very careful with how much oil I used on the air filter. Or I so I thought.

Anyway, this time I cleaned out only the pilot air jet and passage (on the air box side of the carb) and put the carb back in. Voila! Bog gone again!

So I guess I am an expert on how much oil is too much.

Newbies beware! If you have a bog down low, look at cleaning out your pilot air jet/passage and adjusting the fuel screw before you look elsewhere.


Steve T

[ March 31, 2002: Message edited by: skthom2320 ]


Why is it in need of cleaning so quick ?

Are you sure the Air filter is sealed properly ?

Do you have a filter on the Gas line ?

Is cannondale really gonna Make it ?

All the same questions running through my mind!

(1) Is the air filter sealed?

I have a pro-seal gasket and always make sure that things are well seated. I also always check for signs of dust in the airboot and clean out the airbox religiously.

(2) DO you have a filter on the gas line.

Yep - first thing I did to the bike.

My theory is that I REALLY overoiled it the first time around and that there was still filter oil in the air boot. When I ran my finger on it (the airboot) it was a bit sticky. Oops. I was a little nervous with how much oil there was on the inside of the filter that one time...


If it happens again I am going to look for something else but I am pretty sure it was just that doggone overoiled filter.

:) Just a suggestion

if it were me, I would yank the air box completly off and steam the blankity blank

I mean just clean the bajeepers out of it making sure ther is no residue at all, just brand new clean spanking plastic. The clean the ruber from the boot to ther carb.

If it were me. There may be a tear or hole in the boot or a crack in the seam of the air box, just a good once over... :D

That's just what I will do. Thanks for pointing that out.

Had problem w/ bogging, no fun jumping thru rythem section,jump on the gas on down side of jump- BOG. Had to fix this problem in hurry!

Bought 2 UNI filters, clean filter every time I ride. I use KLOTZ foam filter oil, remove outer filter, squirt a (little) foam in palm of hand, rub it into both palms, then onto outer side of filter. No more teeth marks on my handlebar guard.

A word to the wise- start bike before putting on your helmet,goggles,gloves,etc....

Update - I cleaned the airbox thoroughly, took it off the bike, took it apart, etc.

Found a clump of rim grease inside the boot which I got rid of.

Anyway, I think I spoke too soon when I said it was gone above. Out at the track with the bike good and warm, I could still notice a little hesitation with my clean airboot/carb/air filter that wouldn't go away with fuel screw adjustment.

Completely disappointed, I decided to try raising the clip one position (leaning the needle) two days ago.

Result? I rode at the track yesterday and today and enjoyed crisp throttle response off idle and a fast revving engine all the way to WOT. Woohoo! What fun it was.

My theory is that I started riding the bike last October and never really experienced warmer/humid weather until recently. Not only that, but I have vastly improved my riding skills in the six months I have been riding. Maybe I just didn't notice before and have always needed a leaner needle when it got over 70 degrees!

Don't get me wrong though. I had a "bad bog" at first. This was much improved with a good carb cleaning. Then it got warm/humid and I still felt a minor hestitation that I didn't notice before. Leaner needle cleaned it up.

Thanks for all the comments.

[ April 06, 2002: Message edited by: skthom2320 ]

[ April 06, 2002: Message edited by: skthom2320 ]

[ April 06, 2002: Message edited by: skthom2320 ]

My bike recently started fouling plugs again after a new cdi seemed to completely fix that. I read the posts on disconnecting the light blue wire on the cdi to fix this ... after this mod my bike ran great HOWEVER, I fouled one more plug in three rides and noticed a big cough on the bottom when I crank the throttle, also a little cough coming out of corners hard in the middle of the power range. I'm thinking, what the heck?

Turns out that after reading you guys talking about fuel screws falling out ??? I checked mine, it's gone! It was only 1 1/2 turns out. When I get my new one, I'm making one of those little tools to get in there and I'm checking it every ride.

Knock on wood I have not lost me screw :) Well Thats my story and I am sticking with it.

I learned along time ago that a little teflon tape really helps.

I always on any screw that has a spring or is not entirely locked down some how.

Place a small thread of teflon tape at the very end or the top of the screw. Meaning at the end of nearest the head. Making sure that at least one good turn of teflon is in the threads.

Teflon will obsorb some of the vibes, it will also make for a good seel around the threads. The Carb s amajor vacum, any "I MEAN ANY" area that has a potential ti suck in air must be sealed, even idle screws, air screws and pilots.

Draw back is maint is mandatory after each day or so......Teflon falls apart :D

Just my Buck twenty


Congrats happy flying :D

[ April 07, 2002: Message edited by: EgoAhole ]

What do you mean when you say that "it has spark easy"? Are you say that you had no spark before changing the plug and now that you've installed a new plug, you have a detectable spark? If this is the case, I'd look at one of three things. Coil, spark plug cap, or spark plug. It's not uncommon for the cap to go bad. The manual describes how to check the cap.

Upon further inspection I have found that my fuel screw is not gone. I put a really thin screw driver up there and it slid past the screw because of the angle. You see I couldn't rotate my carb to get at it better as my tools were not here, but now that I have checked it properly, it's there and it's fine.

I tried to start my bike ... it's dead again.

There is no spark on the plug. My plug is a light black colour with a little tan on the tip. It looks good but no spark. I put a new one in and it has spark easy. What the heck is going on ???

I'm about to do the electrical tests that are in the manual for some explanations.

The weather is going to turn warm here in this coming week and if my bike won't run I'm going to snap !!

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