So after putting the Savage on a major diet, I have my '96 back together and I'm loving it.  I swapped out all the airbox junk for a Ryca cone style filter and a little Biltwell muffler on the stock header pipe.

Ordered Lancer's kit, and I bumped the pilot jet up to a 55 and the main to a 150.  Also did the white spacer mod.  The petcock has also been replaced with whatever the board recommended alternative part (from a Raptor?) is.

Other than the jetting stuff, petcock, intake, and exhaust, the engine is totally stock.

Bike idles fine and starts up fine with no choke.  Runs fine and seems to accelerate fine at normal speeds (like driving around on 35 or 45mph roads).  Performs well up to around 50mph.

The problem is when I'm hitting highway speeds or really getting on the throttle, the bike stumbles.  Almost like it cuts out for a split second, then picks right back up, which gives it sort of a "surging" feeling.  This happens if I'm holding a constant speed (like in the 60+ mph range) or if I'm accelerating hard.  When holding a constant speed, it does it pretty frequently, like 3 times in 10 seconds, but sometimes it will be fine for a mile or two.

I'm able to run at an indicated 70 or 75mph, so it isn't like the bike is completely neutered or incapable of speed.  

My next idea is to bump up one more size on the main jet, since I have such a free flowing intake / exhaust setup.  Thoughts?

Dave, that is the most succinct set of instructions, for carb tuning, I've ever read on this site. That post should be made into a sticky!

Thanks for the advice, Dave!  I'll see if I can head out this weekend and try that.  Unfortunately, in my mess of a garage, I can't seem to find the rest of Lancer's kit    Have to see if I can dig the rest of the jets out from wherever I put them.

Batman, I was thinking about the back pressure issue when I bought the Biltwell, but I figured I'd give it a go, since the look of the Biltwell was exactly what I wanted.  I may give a shot at welding up some "lollipop" baffles and seeing if that helps.

It sounds like ultimately, that may be my problem.  The bike may have done higher than the 70-75 that I got it to, but (much like the Ninja 250 that I used to own) I hate pushing a bike on the highway when it sounds like it's about to explode.  In my head, I know the bike can take it, but I'm used to sportier bikes that can sit at 80mph for hours and not break a sweat.

https://www.bing.com/search?pc=SOWI&form=AMZNS2&q=engine+intake+design+theory

Thanks, Lancer.  My guess is the muffler is a big part of the problem.  I may take a shot at constructing some sort of baffle for it.  

At the very least, I think the neighbors will appreciate that

I agree with Vercy,also the length of the intake matters,checkout ;                       www.bgsoflex.com/intakeln.html       ( be aware that the intake length is the total length between the intake valve through to the air filter - 1/2 the  inside diameter of the hose your using.)You might try what we do to restore the baffles in a Dyna muffler ,that is to drive a soft plug (the kind used in to plug the water jackets on auto heads) half way down your muffler ,forcing the exhaust to move around the baffle giving you some back pressure,pick the proper size and drive it in from the forward end.If you find it to be to much you can drill a hole in the center of the plug start small and drill larger if needed,go slow as the noise will increase and the backpressure will drop as the hole gets larger.You may see a lot of bluing on the muffler as the exhaust gases are forced around the baffle ,how much will depend on the Biltwell.

No , I think he means the longer straight section should be attached to the carb,as this straightens the air flow into the mouth of the carb.(ideal)Right now the air tends to hug the outside of the elbow making the air denser at the top as it enters the carb,but the slide opens from the bottom ,and that is where the air needs to be to readily mix with the fuel.(the carb is at part throttle ,slide less than half open @ 60MPH, most of the time during normal driving ).

People modify things that they have never studied. It's not hard to read a little. Ever notice how much better it is having a big straw in the malt? Intake changes have a big impact because there is no piston shoving air out, it's creating a low pressure area and if the design doesn't make it easy for air to flow and get gasoline dispersed evenly through it, it's not a great intake design.
There's a link to a header design video that is really good, but I don't know where it is.
My intake design link may not be the best out there.


justin_o_guy2 wrote on 09/22/17 at 04:54:55: