Tune-up questions

I have a 2007 Interceptor VFR800. The bike has 15,750 miles on it so the time is quickly approaching for the first valve adjustment (Honda recommends doing a valve adjustment at 16,000 miles). Many questions:

1. In theory, tightening up the valve lash would generate increased valve lift ... which would make for better power. Has anyone noticed a performance improvement after a valve adjustment? (Likely not)

2. When the engine is torn apart to do the valve adjustment, is there anything else that warrants checking/adjusting/replacement? (the two cam chain tensioners have already been replaced on my VFR)

3. Does anyone know what Honda's recommendation is regarding at what point the spark plugs should be replaced?

4. If I replace the spark plugs, is there a particular brand/model/heat range/etc. spark plug that VFR'ers have found to perform better than the stock plugs?

 

As far as plug replacement intervals.



What would you really gain by setting the valves to anything other than spec?

 

John, I would be very careful with setting the valve lash to anything tighter than minimum spec. In essence, a loose lash will produce noisier valvetrain, but it will not affect the flow of air-fuel mix by a significant margin, so it is a far better option to have a larger valve lash than a tight one.

Now, valves are adjusted when the engine is cold. Do not forget that metal expands when heated up, and engine will be quite hot when running. Therefore, this valve clearance will actually be smaller when engine is hot. If you adjust them too tight, you are risking the metal stems expanding and not closing the valves all the way, thus loosing compression, but even worse, burning the valves.

Now, $64k question is, how low can you go ...... with valve clearance otstir:

 

Actually, it was never my intension to adjust the valves to a tighter than normal spec. Rather, I was just wondering if there would be any noticeable improvement in power (likely not) after resetting loose valves to the factory spec.

In any case, my other question is more important to me ... if I replace the spark plugs, is there a better plug choice than stock? Platinum or iridium, a step hotter or cooler, normal versus projected tip, etc.

 

ONE of the reasons for a gap is to ensure sufficient lubrication between moving parts

 

Dang, 16k on the plugs....the 5th gens or only 8k :frown:
I stick with the factory NGK plugs. Did the first ones at 10k and all was good. Was forgetfull and these last plugs went to 12k and the engine started running like crap.
Seems very few 5th or 6th gens that have been checked need valve adjustment at 16k. I'm at 22k and unless I hear any noises or see a change in performance I'm going to wait until 30k-32k when I'm due for plugs again.

 

The iridium NGK plugs can extend change interval by 3-5 timea. I've seen them easily go over 100, 000 miles in auto applications.

 

I think I will take a chance and wait till the next service interval !!