Once installed, the Super-E almost looked like it belonged on the Savage.

Excellent post. Informative, to the point and even entertaining. Great science Mike. I’ve used 3 of these carbs (never had a Super E) as well as others (my DRZ has an MX39 pumper...a real pia to diagnose). I think the most important aspect of any carb is to understand how it works and what each jet and passage does. With that understanding tuning, maintenance and troubleshooting become very easy. As you proved/showed in your last carb comparison, at WOT there isn’t a big difference between carbs with similar Venturi openings. However throttle response can be very different. I find that the stock carb works very well on my mostly stock engine. However, if I ever install performance cams and a HC piston, I’ll be looking for a VM kit for sure.

DragBikeMike wrote on 03/28/20 at 23:44:18:


Mike:  Great review, and it supports my experience with this bike.

I am not a drag racer - my engine modifications were intended to make a better running engine.  Not necessary the best - but better.  My rides are generally on 40-60 mph twisty back roads, and my rides are spirited -but generally don't require more than 1/2 throttle at any point during the rides.  I stay at the speed limits on the straight sections, and I try not to slow down much for corners......my fun is on the curves!

I ran the stock carb and air box and paper filter for a year after adding the Wiseco 95mm, performance cam, head porting and less restrictive exhaust.  The engine ran great and was a lot more fun than the stock engine.  When I switched to the Mikuni VM38, the only real change I noticed was a bit faster throttle response - but we are talking tenths of a second of change.....it just felt like the throttle was more directly connected to the engine.  On a normal ride either carb proved to work very well as I tend to roll on the throttle - I seldom "wack" open the throttle instantly.

The only negative I have about the VM38 - is that if you set the carb up for a 1,100 RPM idle, and you have to do a panic stop and pull in the clutch and chop the throttle instantly while you brake hard - the engine can stall as a result of the instantly closed throttle.  The higher compression piston and light flywheel may also contribute to the problem.  I believe the stock CV carb and TEV valve are a bit more reliable in the chopped throttle scenario.  Rejetting the carb richer at idle or increasing the idle speed would help with the chopped throttle stalling scenario - but the current jetting is set up so the bike runs well during normal operation, and I am not willing to rejet to resolve an issue that only occurs a couple times a summer.

So......I am supporting the use of the stock carb - it really is a decent carb.

This shows the O2 sensor in the muffler.

Dave, I agree the stock carb suits your riding style.  It’s in the sweet spot right where you do most of your work.  Power delivery is linear.  Very good match.  BTW, I also experienced that panic stop stall with the VM.  It only happened once.  Mikuni used a baffle on some of the older off-road applications.  It supposedly prevented the fuel from sloshing around in the float bowl.  That part might still be available.  It was held in place by the main jet (as I recall).  If you look at the picture of the PWK internals, Keihin appears to have incorporated a similar built-in baffle that should mitigate fuel slosh.

DragBikeMike wrote on 03/30/20 at 15:33:11:

The edelbrock quicksilver has a baffle and foam in the lower half of the bowl.

Lectron seems to give out a few of their carbs for review, given DBM's testing methods and experience with many carbs it might be worth and email to get one for testing and sharing info with the forum community. If they're as good as they say/seem then I would think they'd love the testing and possible new market.

Also thunderproducts has a baffle for the VM's.