Author Topic: WEIRD iDLE DROP .......  (Read 12168 times)

Offline GR8LITE

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WEIRD iDLE DROP .......
« on: April 15, 2016, 03:13:50 PM »
 Good Day all!

 Bike is running ..... seems to be ok!

 Twist throttle , engine revs , let throttle close ... engine idles down to approx 2000 rpm , ten ever so slowly idle drops to around 1500 rpm , slowly , very slowly. Just the last 500 rpm drop is slow..... weird can't figure it out.

 Thanks , I'm only worrying about this to keep from thinking about the bluish smoke its blowing out the exhaust ...... maybe it'll go away with time ......

Offline Squishy

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Re: WEIRD iDLE DROP .......
« Reply #1 on: April 15, 2016, 03:59:07 PM »
Good Day all!

 Bike is running ..... seems to be ok!

 Twist throttle , engine revs , let throttle close ... engine idles down to approx 2000 rpm , ten ever so slowly idle drops to around 1500 rpm , slowly , very slowly. Just the last 500 rpm drop is slow..... weird can't figure it out.

 Thanks , I'm only worrying about this to keep from thinking about the bluish smoke its blowing out the exhaust ...... maybe it'll go away with time ......
Too lean mixture:
1) False air (air-leak). Carefully spray carb-cleaner/starterfluid around the in-take tubbers and see if idle changes.

2) Mixture screws set way too lean. Set to 2x out.

That, or extremely de-synchronized carbs.

Offline GSF

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Re: WEIRD iDLE DROP .......
« Reply #2 on: April 16, 2016, 02:04:04 PM »
... I'm only worrying about this to keep from thinking about the bluish smoke its blowing out the exhaust ...... maybe it'll go away with time ......

The good news is the blue smoke will disappear when your engine runs out of oil  :beers:

The bad news...

Offline greg737

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Re: WEIRD iDLE DROP .......
« Reply #3 on: April 16, 2016, 05:03:22 PM »
What would be the rank-order of the ways that oil ends up in the combustion chamber?  I can only think of two: down through the valve stem seals or up around the piston rings.  Valve stem seals would probably be easier to replace than the piston rings, but probably not by much.

Offline Squishy

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Re: WEIRD iDLE DROP .......
« Reply #4 on: April 17, 2016, 05:13:08 AM »
What would be the rank-order of the ways that oil ends up in the combustion chamber?  I can only think of two: down through the valve stem seals or up around the piston rings.  Valve stem seals would probably be easier to replace than the piston rings, but probably not by much.
Yes.
Blue smoke when applying (full) throttle = piston rings.
Blue smoke when closing throttle (at high rpm)  = valve seats or similar.