Author Topic: suddenly too rich  (Read 24960 times)

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Offline matzilla

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Re: suddenly too rich
« Reply #15 on: May 10, 2010, 12:17:55 AM »
yesterday after work i pulled the carb and cleaned it again. blew out the different circuits and all the vent lines. went back to original jetting and worked my way back through the pilot jets back down to a 55. it seems inconsistent. it will respond well for a couple trips up the street, then it sounds like it loads up the pilot circuit again. then i put my uni filter on and it did the same thing. i think i may have to pull my exhaust and look at things. i can see up the silencer, no packing obstructing. if i can't find anything wrong in the exhaust side i might have to pay my friend to fix it. i am getting frustrated.

Offline Hillclimb#42

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Re: suddenly too rich
« Reply #16 on: May 10, 2010, 12:19:47 AM »
Did you wind up looking at your reeds? When mine sucked a petal, it lost power. It idled, but fell on its face with a handful of throttle. But that was pretty consistent. No chance you are running old fuel? sounds like you ride too much for old fuel, but just rambling on about possibly overlooked issues. Did you try a new plug? I have had new ones that didn't work right.
« Last Edit: May 10, 2010, 12:27:45 AM by Hillclimb#42 »

Offline cbxracer30

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Re: suddenly too rich
« Reply #17 on: May 10, 2010, 12:45:13 PM »
What about a bad crank seal on the clutch side . It's now rich , it's oil foul .  Everytime our 5's go extremely rich it's the crank seal clutch side - extremely lean suddenly crank seal flywheel side. CBX
Yep, you can ride it - if YOU can start it !!

Offline matzilla

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Re: suddenly too rich
« Reply #18 on: May 10, 2010, 01:24:36 PM »
oh i hope that isn't it. what a pain. just put it together in november. oem seals.

Offline Friar-Tuck

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Re: suddenly too rich
« Reply #19 on: May 10, 2010, 01:31:24 PM »
 Matt,
Like CBX mentioned, without any other changes to the bike the crank seal would be a likely suspect.  The ones I had go bad did so in pretty short order.   Like one ride the bike was running like a scalded Dawg and the next time I took the bike out I fouled a plug trying to start her up.  No rhyme or reason, just Ka-Poot.
  You also had a question on the Vent lines in the air box. 
The pulses in the airbox of a single or twin can be a pretty big boom to something as sensitive as carburation.   
  Every time the piston moves up and down their are some pretty big gulps of air rushing in to the engine and then getting stopped in it's tracks as the ports and reeds open and close.   Those pulse waves also can affect the fuel in your carb.
   Just like manipulating a liquid in a glass with a straw the same thing is going on in the carb bowl if the vent lines are terminated in your air box.    I had run mine in the airbox also and didn't notice any changes except less dust in the vent lines.
 Some more experienced riders Claimed it messed with their jetting.   I now run my vent lines up along the backbone of the frame and the fuel tank.  no problems...yet...
   Tuck\o/ 
"The Truth Has No Agenda"

Offline matzilla

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Re: suddenly too rich
« Reply #20 on: May 10, 2010, 01:33:17 PM »
would that discolor my oil? or affect my oil level? oil is still super clean and has not dropped at all.

Offline matzilla

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Re: suddenly too rich
« Reply #21 on: May 10, 2010, 01:53:23 PM »
after i posed the question about the vent lines i moved them back to their stock location, though it made no difference. the reeds look great, power valves are clean and rotate easily. i need to check the flywheel key still. i can see clean through my silencer, but am unsure of the packing's condition, or how it would affect exhaust flow. but it is not obstructing it.

on  a side note i welded my broken upper pipe mount right before all this happened. but i took all of the electronics off the bike first, so i don't think that it is related unless i have a bad connection now that it is back together.

i want to thank you all for all of your input. there is so much experience here on this site. i check several times a day from my phone and am posting from it now. thanks again and pray it isn't my main seal. ugh!

Offline Friar-Tuck

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Re: suddenly too rich
« Reply #22 on: May 10, 2010, 02:01:03 PM »
You would see a drop in the tranny oil level.
  Since the oil gets sucked out of the tranny and into the crankcase there is usually no other indication.
(I could actually smell the trans oil on the plug I had oil fouled.)
  Tuck\o/
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Offline matzilla

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Re: suddenly too rich
« Reply #23 on: May 10, 2010, 02:29:19 PM »
Key is secure!  I did notice a very small amount of oil sitting in there though.  a tiny amount, just enough to feel the slick on my finger after wiping it out. maybe 2 drops?  Is this normal? could that just be from the couple times that I have forgotten to pull the wash plug before trying to start it?  This is about to be a can of worms, I can feel it.

Offline k5abuser

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Re: suddenly too rich
« Reply #24 on: May 10, 2010, 04:46:01 PM »
funny you mention the vent tube. the only other change i have made was routing the bowl vents up to the air box. is it possible for this to affect float levels or create some kind of pressure drop in the bowl?



 routing the vent tubes thur the air box could cause it to pull vacume from the bowl which could put fuel in the air box and more fuel in the air before  going into the carb.also the wasp could plug the hole up . it happens around here more than you now .
race gas is fast but Q16 hauls azz.i still ride because i am not ready to have been that fast. i ride a kx500 because they don't make a kx600!ck k5abuser on youtube

Offline Goat

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Re: suddenly too rich
« Reply #25 on: May 11, 2010, 01:15:19 AM »
Key is secure!  I did notice a very small amount of oil sitting in there though.  a tiny amount, just enough to feel the slick on my finger after wiping it out. maybe 2 drops?  Is this normal? could that just be from the couple times that I have forgotten to pull the wash plug before trying to start it?  This is about to be a can of worms, I can feel it.

I would do a leak down test (pressure test, vacuum test) whichever you prefer to call it. That would tell you if your seal is leaking or not. Not sure if you have done this before or have the tools but here is a link to get you started. http://www.kxriders.com/forums/index.php/topic,6608.0.html Hope this helps.
It's hard to keep a drivers license riding a 2 stroke dirt bike on the street.  If you drive within the law they are VERY boring.

Offline cbxracer30

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Re: suddenly too rich
« Reply #26 on: May 11, 2010, 03:15:23 AM »
would that discolor my oil? or affect my oil level? oil is still super clean and has not dropped at all.
No it won't discolor the oil , It sucks it into the crankcase , and there is almost a quart of oil in there , it doesn't take much case oil to foul the plug .CBX
Yep, you can ride it - if YOU can start it !!

Offline matzilla

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Re: suddenly too rich
« Reply #27 on: May 11, 2010, 02:03:01 PM »
I'm working on putting together the necessary pieces to vacuum test my motor. when testing should i test with the crank in different positions? or maybe slowly rotate the crank

Offline Goat

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Re: suddenly too rich
« Reply #28 on: May 11, 2010, 02:17:48 PM »
I don't think it matters what position the crank is in. I've personally never done a leak down test. When I rebuild the top end I replace the crank seals as well. Keeps the down time to a minimum so I have more seat time.
It's hard to keep a drivers license riding a 2 stroke dirt bike on the street.  If you drive within the law they are VERY boring.

Offline k5abuser

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Re: suddenly too rich
« Reply #29 on: May 11, 2010, 03:22:40 PM »
I'm working on putting together the necessary pieces to vacuum test my motor. when testing should i test with the crank in different positions? or maybe slowly rotate the crank


 you have to block off the exhaust and intake to get  the leak down to work . most leak down tools for this hook up to the intake side.it does not matteras the leak down will bypass the rings . now if your head gasket is leakin yo find that out too. this test is for your main seals mainly.hope this helps
 
race gas is fast but Q16 hauls azz.i still ride because i am not ready to have been that fast. i ride a kx500 because they don't make a kx600!ck k5abuser on youtube