[kd1yt]

Hello all
I'm thinking that I may eventually want a tachometer for my 2009 AVL scrambler. Not urgent but kind of want to keep my eyes open in case I run across a suitable one at a good price. In terms of knowing which tachs will be compatible, am I deducing correctly that the AVL, with (I think?) its ignition timed by a separate pickup coil down in the crank-mounted alternator- is therefore a 'wasted spark' engine that fires the spark plug once per crank revolution, not just on the actual combustion stroke? Thanks in advance for helping me answer this!

[Adrian II]

Yes, there is a spark every revolution of the crank, so it's a "wasted spark" system as you correctly deduced!

A.

[heloego]

   Already knowing about the wasted spark I fitted mine with a TTO digital tach. Even with it set at ".5" I just need to divide the reading by 2 to judge my rpm.

[tooseevee]

   Already knowing about the wasted spark I fitted mine with a TTO digital tach. Even with it set at ".5" I just need to divide the reading by 2 to judge my rpm.

            I don't get it. Mine read RPM fine. It was only inaccurate out on the road where it never settled on a steady number. It just constantly jumped from one number to another.

            If you set yours for one spark per revolution (I set mine at 1 for one spark per crank revolution) it will read the actual RPM number. I believe .5 is for one spark every other revolution (only on compression stroke) as in a single fire ignition. RE is not a single fire ignition.

              I didn't leave it on my bike very long because it wandered all over the place out on the road and was very distracting. It was good for tweaking idle speed as the engine warmed up, etc., that was about it.

[heloego]

   I had set it at .5 due to that was what the setting is for my UCE.
   I'll change it to 1 and see how it does.
 

[tooseevee]

   I had set it at .5 due to that was what the setting is for my UCE.
   I'll change it to 1 and see how it does.
 

           
             I didn't realize the UCEs were single fire. (But there's a lot nowadays I don't realize  or want to).

              This is a later edit to my above:

                        I shouldn't be using the term single fire as I did above for enfields. What I mean is a spark for every TDC, hence the "wasted" spark on exhaust terminology. But we all know what we mean, don't we ?  

                         Single and Dual fire have different meanings in my head. But, then, so do a lot of things

[heloego]

   Thanks for the tip!
   Just took her for a run after bumping it up to a 1.
   Of course, it did make a difference.  It does hunt a bit for me at all RPM, but not enough to bug me. Easy enough to garner an average RPM.
   At Idle it gives me a +/- of about 50 RPM, then increases to about +/- 90 RPM at speed.
   I can live with that for now 'cuz until further notice not sure I can justify the $$$ for a better tach.

   Side Note: Just finished cleaning it up after replacing the exhaust gasket. The Goldstar header I received is always a bitch to install, but I think I got it seated better this time. Hope it works 'cuz I'm now on my last gasket until REFW finishes getting set up, and after today I don't get to ride for another week due to work. 

[Adrian II]

No header pipe gasket on mine, just good old silicone RTV, no special heat-resistant grade needed either!

A.

[heloego]

   Well, that would certainly save a few $$$. 
   Just got in another ride this afternoon. No visible leak at this time, so fingers crossed. 

   Checked the head temp with a Laser temp checker after the ride. 258 F/125 C.
 

[AVL Power!]

No header pipe gasket on mine, just good old silicone RTV, no special heat-resistant grade needed either!

A.

Sorry to go off-topic, A do you mean to say that you are not using the Exhaust gasket, the steel insert which Paul used to open up by 2mm? any idea what are the trade offs? I would love to go gasket less but any sealant works?

Regards,
Sanket

[Adrian II]

No, I didn't use the steel insert, or any exhuast gasket, just the fixed flange on the pipe butting up against the outside of the exhaust port, sealed with ordinary silicone RTV goo and held on by the loose flange secured by the two M8 nuts. The muffler/silencer mounting secures the other end of the pipe. I did try specialist exhaust putty to seal the pipe in the cylinder head at first, but it was completely useless.

As I had opened out the very restrictive exhaust port in the cylinder head, there seemed no point in putting that restriction back by fitting the steel insert.

A.

[AVL Power!]

Thanks A That's pretty much like drop the exhaust gasket and seal it off for leaks and done! I gotta try this one out. My exhaust is pretty restrictive, so this should help!

[Adrian II]

Sanket, this won't help much by itself if the rest of the exhaust is restrictive!

To get the best of all your bike's tuning modifications you need an exhaust pipe with NO internal restrictions, and then you need a reasonably free-flowing muffler/silencer with just enough baffles to control the noise without stifling the gas flow. The best one I ever used was a genuine RE factory short bottle silencer, which I suspect they no longer supply.

A.

[AVL Power!]

I got ya, currently using a stock header pipe with no cat-con. Custom made exhaust with literally no restriction. I will try going gasketless, sounds like a good idea!