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Slide sticking closed but bike winds out like it's stuck open!?

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Went riding in the mountains last Saturday.

 

Spun carb to get under the bowl, pulled main jet, checked to make sure I had correct one in, then replaced.

 

Bike started up just fine, started warming it up. 

 

I forgot to turn off the choke though.. as it warmed I started revving it a bit to clear the chamber out like I usually do.

 

Realized it was running boggy, DUH the choke is still on, turned it off and everything normal.

 

Rode about 50 yards out the lot and throttle sticks wide open. Shut bike off, play with cable, seems like it's sticking, play with the cable, seems to free it, start bike and it revvs out immediately.

 

Pulled airbox and carb off. Slide is definitely sticking DOWN, or CLOSED. Seems to be hanging up on the piece of brass shrowd that surrounds the needle at the bottom..

 

These seem totally unrelated condtions!? 

 

I'm stumped to say the least.

 

Cable is good.

 

Reeds look good...

 

IDEAS PLEASE.

Edited by MotoGuido

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sounds like a possible air leak somewhere. 

 

I agree but the bike revving out suddenly after being fine a moment prior.  Acting like a stuck throttle with no prior warning. Just weird an air leak usually begins to pull extra air and mess up your idle before it gets to the point of revving out like this.  

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possible that when spinning the carb in the boot tore the intake boot ?   I don't see that happing and would be rare,But just throwing out ideas lol.

 

I'm open to all ideas.  But no the intake boot is intact. Removed the entire intake and reed cage. All look normal. 

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Exact problem happened on my 05 CR250 last Saturday. I have not had a chance to tare down yet, came looking for ansewers over here? :rolleyes:

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Exact problem happened on my 05 CR250 last Saturday. I have not had a chance to tare down yet, came looking for ansewers over here? :rolleyes:

 

 

Disassembled carb. Found a tiny chunk of brass stuck in the needle jet was wedging the needle in there. Slide moves freely now.  Gonna reassemble and look for air leaks if it keeps revving up..  Hopefully this was the only problem!!

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Just pulled the cover on the stator and found oil in there..  so obviously the crank seal went to.  

 

Coincidence? We shall see..

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Exact problem happened on my 05 CR250 last Saturday. I have not had a chance to tare down yet, came looking for ansewers over here? :rolleyes:

I'm completely stumped!  Tore carb apart, all looked fine. Went to start, same thing....acting as if throttle stuck open? Tore carb down again, clean & in spec...Still throttle stuck?

Pulled ign/flywheel cover, dry..no oil leaking. Installed stock reed valve cage just to check ( stock reeds only had 1-2 hrs B4 I up-graded to V-Force)

Still throttle stuck! Hate to take in to the shop $$$ :( 

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Replaced left side crank seal. Bike runs normal now!  I have no idea how these conditions occurred at the exact same instant!!??   I may never know..  

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I'm completely stumped!  Tore carb apart, all looked fine. Went to start, same thing....acting as if throttle stuck open? Tore carb down again, clean & in spec...Still throttle stuck?

Pulled ign/flywheel cover, dry..no oil leaking. Installed stock reed valve cage just to check ( stock reeds only had 1-2 hrs B4 I up-graded to V-Force)

Still throttle stuck! Hate to take in to the shop $$$ :(

 

Use soapy water in a spray bottle to find air leaks.  Could be on your clutch side as well

Edited by MotoGuido

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Well took the bike to the track.. 

 

Ran well for a few laps.. then bogged like hell coming off a 4th gear jump barely made the landing and I could tell the bike was toast.  

 

Went to kick it over and has basically no compression.. guessing the ring is toasted? 

 

Pulled the left side cover again just to check and found a little oil in there again.. hmmm... Now I'm really confused!!??

 

Awe hell back to square one..

 

picard-facepalm-hotlink.jpg

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After a few days enough oil pooled there to see that it's red, therefore from my transmission.. hmm

 

Top end is toast, looks like it took out the cylinder plating too.. so this is gonna be a little more expensive than I had hoped..

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hopefully your bottom end is fine at least.

ensure u installed the seal in the correct direction, some want the LH crank seal installed with the writing facing IN, tho CR's are all 'normal' afaik.

is indeed odd that a *correct* new seal died that fast.  (unless it was one of those cheap/china seals, sometimes those are junk.)

But, fwiw, our $$$ chainsaws at the mill began to eating crank seals and sticking rings on the ex side until we both:

a. switched 2T oil to an ester synthetic mix (even tho the original 2T oil blender swore up and down that their formula had not changed)

b. AND we paid for high octane ethanol-free gasoline, at the request of Husqvarna. 

lots of theories on the exact culprit/chain of events there, but bottom line is that the problem went away. immediately.

tear-downs would indicate "lack of lubrication", but pressure-tests showed leaking LH crank seals. 

we have had not one single failure since, been 6mos.

Polaris also insists that ethanol gasoline IS indeed a type of oxygenated fuel---and you know the risks/caveats of that fuel in a 2T...

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hopefully your bottom end is fine at least.

ensure u installed the seal in the correct direction, some want the LH crank seal installed with the writing facing IN, tho CR's are all 'normal' afaik.

is indeed odd that a *correct* new seal died that fast.  (unless it was one of those cheap/china seals, sometimes those are junk.)

But, fwiw, our $$$ chainsaws at the mill began to eating crank seals and sticking rings on the ex side until we both:

a. switched 2T oil to an ester synthetic mix (even tho the original 2T oil blender swore up and down that their formula had not changed)

b. AND we paid for high octane ethanol-free gasoline, at the request of Husqvarna. 

lots of theories on the exact culprit/chain of events there, but bottom line is that the problem went away. immediately.

tear-downs would indicate "lack of lubrication", but pressure-tests showed leaking LH crank seals. 

we have had not one single failure since, been 6mos.

Polaris also insists that ethanol gasoline IS indeed a type of oxygenated fuel---and you know the risks/caveats of that fuel in a 2T...

 

Seal is a Honda factory seal. Drove 2hrs round trip just to get it..  

 

After oil pooled in the stator area there for a few days it showed red so it's trans lube for sure coming from the clutch I guess??

 

Top end has a nice gouge in cylinder at the exhaust port and a busted up piston in the same spot. 

 

Talked with Terry Varner and he basically described my cylinder in piston to me before I could even tell him what it looked like..  Said it was from detonation.  

 

So I'm sending it off for a replate and having the head modded at the very least, try to get this thing running better next time.

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