2010 D8 low idle issue

[SU27]

Hello guys,
I work on my 2nd 2010 Switchback 800, and noticed next issue: when engine starts, it runs on lower than should RPM - 1400, and then when engine warms up, it drops to 1000-1100 - headlight is fading (but not shutting down). As well, it handles reving up in bad way - engine shuts aftyer releasing throttle lever. What it could be?:face-icon-small-dis

 

[snowman80]

I'd check the compression.

 

[SU27]

I'd check the compression.

110. MTNTK kit is sitting right beside the sled. i do not want starting putting it on before i figure out what`s wrong. engine has only 20 hrs and 220 kms on it

 

[richracer1]

The usual culprit is a TPS out of adjustment. Get it checked, then go from there.

 

[Snow Duck]

As above tps and voltage regulator.. has caused some issues also.

 

[SU27]

Ok guys, i will take cylinder and pistons off today. Hopefully monoblock is not damaged. That would be bad bad thing. I am doing it first time in my life. Any tips?

 

[Snow Duck]

CHECK AND DOUBLE CHECK all clearances..run out on crank ect..mine was all good but i triple checked all...i ordered my renic mono from us crome..it was around five hundred without core i would recommend just ordering a new mono also for that price is cheap insurance...

 

[SU27]

CHECK AND DOUBLE CHECK all clearances..run out on crank ect..mine was all good but i triple checked all...i ordered my renic mono from us crome..it was around five hundred without core i would recommend just ordering a new mono also for that price is cheap insurance...

My thought its a rings problem coz sled was parked for 2years outside and never been fogged. Is re honing mandatory in this case?
Clearances: ring end gap, piston to cylinder, what else?

 

[SU27]

Took monoblock off - looks like its healthy - no scratches, nicasil is not worn. There is a millimiter of carbon build up on pistons, exaust system is filled with dirty oil, VES filled with the same oil. Filthy. I might be mistaking, but it looks like piston rings ends were not inline with pins.
I do not know how is it possible to get engine from brand new to condition like this in just 200 km.
on MTNTK kit - checked piston ring end gap - as it should be - 0.019". Tomorrow will bring cylinder block to dealer for measurements and possible honing.
Question: before i will start to assemble engine, what should i check out? What could cause this to engine?

 

[diamonddave]

Please hone your cylinders. You will be very happy with the MTNTK kit.

The low idle is either low compression, ring wear that doesn't show in low compression, or TPS adjustment.

 

[SU27]

The cylinder is with dealer, and will be honed next week. As well, they will check ALL the clearances, etc. :cheer2:
Quite pricey for everything - 120 CAD

 

[SU27]

Adjusted TPS on both switchbacks yesterday. Thanks to Mountainhorse and other guys for helpful post inside increase your iq thread.
Both were slightly off, but this "slightly" might mean "a lot" on final result. One was .730, and another was .720 on baseline. 0.945 and 0.920 on idle.
Idle on working one raised from 1750 to 1850, and lilbit erratic (IMHO). I will check it again today with airbox installed.
As well, clutch on working one is sticky - not always disengaging. It means not coming back to open state on idling rpm. Looks like it needs service.
Again, how in the hell people can screw up brand new sleds in just 200 km?

 

[SU27]

finally put my sled together today. Engine and I are happy. Just waiting on primary clutches balancing, then I can fog engines.
Surprisingly installing MTNTK kit was not just easy, but super easy. :juggle: