It’s hard to find any solid info on this because most time you research valve lash it turns up people’s suggestions for what to set. But I was watching a briggs seminar on you tube and the presenter went into a lot of detail about offsetting the exhaust and intake valves by setting the lash about 0.006" difference. He suggested 0.002 on the exhaust and 0.008 on the intake. It’s winter right now so I can’t really test this but I believe this is to separate the two strokes…
What became more confusing (and honestly seemed like he misspoke) is the other well known briggs guy actually said it is 0.002 on the intake and 0.008 on the exhaust. Any one have any idea what I’m going on about, looking for some clarification.
One of the interviews might have been with David Klaus on Kartpulse live?
There does seem to be varying opinions on lash setting, as low as zero I’ve read.
Perhaps someone can post results from testing…
David Claus was the second one I mentioned. I’ll link to the seminar. I just rewatched it, and it’s pretty convincing as far as the benefits go. Basically by reducing the overlap of exhaust/intake it’s giving more power in lower rpms.
That’s the section he discusses it in.
Cams are voodoo and always will be
He is talking about effectively altering cam timing a little by changing the lash.
First thing I would do was worry about reliability - making sure your valves are fully closed and not too loose either. I think the tuning would only be a benefit if you are in podium vicinity and have a pretty good handle on some other stuff first.
What do you mean by affecting the reliability? Do you mean permanently harming the engine/valves? He made it seem like a relatively safe parameter to play around with.
I mean I’d be tempted to just leave them set in a safe range and not fool with them unless you are a consistent front runner.
That is not meant to be an insult to your driving or anything. Just the valve adjustment as tuning wouldn’t be a high priority for me.
I tried exactly what he said on a test day and saw no difference in times. It was on a track that has a good mix of slow and fast corners and long straights.
One thing to keep in mind with any 206 advice is it may be for another slide or ignition than what we are running.
I want to say that whole segment was geared towards a kid class - but not sure.
Just set it at the recommended 0 to .002 lash and go race. Y’all put too much thought into stuff that isn’t going to make you a lick of difference on the track.
I don’t disagree with keeping it simple, but at the same time the recommendation from Briggs has varied over time. I think that’s partly why roller are asking the question.
Yeah at times it seemed like some of it was geared towards green slide but other times not. He made the general statement that the engines like to be really rich in the low rpms for example.
I’m guessing that is because there it no accelerator pump. Running rich helps with that initial rush of air & drop of vacuum.