Throttle Respons/Power Loss After Adjusting Valves

So after this past weekend, i adjusted the valves to spec 0.10 IN and 0.15 EX. After driving it around town, the sound of the bike has a less "tractor" like sound to it and the bike feels spotty and gutless in the lower revs/low throttle position. On top of this, it feels like the bike doesn't have that torque-y "oomph" when i yank back on the throttle. Could i have adjusted the valves too tight? Maybe i need to do a fuel re-map to match the valve adjustment?

Also, i replaced the air filter with a BMC filter, changed the oil to 20w50 full synthetic, and put in NGK iridium plugs. Might that have something to do with it?

Still trying to learn the nuances to this bike!


Thanks!

As it's the last thing you did, check the clearances again. Your guess is probably right.

Put a stock air filter back in. The aftermarket filters are little more than rock strainers. The stock filter flows more than the 8V requires.

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While, of course, it likely has no effect whatever on the (odd) symptoms you report, why 20w50 vice the recommended 10W60?

Good luck on sorting out the power-loss issue.

Bill

The aftermarket filter will of buggered up the breathing, it will take a few hours for it to try and trim around the incorrect parameters introduced by the filter.

My own personal preference would be that anybody who suggests puting a rock strainer air filter on any modern engine should be tarred and feathered and then towed through the streets in a tumbrill before being stuck in the stocks and pelted with rotten fruit and human waste until they give their customers their money back and promise never to do it again.

Second offence means they are locked in a room and forced to listen to Celine Dion records for ten years which is effectively a death sentence!

Look, I've said it a thousand times. The stock filter flows more than enough air for the motor and also takes crap out. BMC's and K & N's and their ilk are labyrinth filters that don't work very well. The idea there is some advantage to them because they are washable is a joke! Over here a stock air filter costs about twenty bucks. A K & N costs multiples of that! You'd likely have to do 100,000Km plus before it became a sensible economic proposition in filters alone and once you throw in the cost of valves, guides and barrels and Pistons because you've dusted your engine by not getting the crap out of the air it starts to look like a seriously crap idea!

Believe us or don't but Mark and I can assure you, unequivocally, that you won't get one iota more performance out of your 8V by using a labyrinth filter. My Stelvio had one in. It was the first thing that got thrown in the bin after it was rollerised. I'd rather spray my privates with lighter fluid and start stringing matches than have one in one of my bikes!

Pete

PS. There are no 'Nuances'. It's a machine. It obeys the laws of physics and engineering.

Another vote to ditch the BMC. Also, there is no reason to run 20W50 other than that's what you can find at the parts store. 10W60 full synthetic is the factory spec and is readily available online and will ship straight to your doorstep. I've found competitive pricing for MOTUL at [You must be registered and logged in to see this link.] and even on Amazon.

Thanks for all the input everyone! Upon the recommendation, i took the BMC filter out and put the old paper filter back in. Noticeable difference on the throttle response for sure. Wow, what a piece of shit (more eloquently put by Pete). Check that off the list. Next step is determining if the valves may be a little too tight and maybe a fuel re-mapping as suggested by Beetle.

Bill, my mechanic recommended 20w50, but i may go back to 10w60 per the manufacturers suggestion.

Your mechanic does know that the oil is also used as a dedicated coolant and is supplied through a separate pump through a separate circuit to cooling galleries around the exhaust valve seats? The oil gets flash-heated to some pretty extreme temperatures, that's why the specification is slightly more critical with the 8V. The oil also gets squirted onto the undersides of the piston crowns for cooling purposes but that comes from the high pressure lubrication circuit.

The 8V motor is not like your grandpa's V7 Ambo.

Pete

So Pete, you're saying I should switch back to 10w60?

Yes, at the next change interval. No point in worrying unduly and if there are problems with the viscosity choice they will likely be cumulative rather than being instantly catastrophic.

Having said that there are probably reasons why a10/60 is specified so why not use it? It's not hard to get a full ester synth 10/60 on line and unless you've had some sort of catastrophe oil isn't something you need at incredibly short notice so just plan ahead a bit. Same with service items like filters and gaskets. Buy a set and keep them one the shelf. If you sell the bike you can always gift them to the next owner.

Pete

10w-60 is becoming pretty easy to find in local stores. As it turns out, BMW (automobiles) is now specifying that weight in M3s and stuff.

But the oil choice does not cause the power loss I think. Maybe the valve clearances have been set somewhere else than in the compression stroke of the appropriate cylinder?