In the immortal words of SGT Schultz on the old TV show Hoggan's Hero's, "Verry Innteresttering"!! Max

Charon wrote on 03/31/09 at 16:33:41:


Doesn't matter.  If we dyno'd our bikes, someone on here would just whine about how we went to one that read high, or that we went to one that needed calibration to account for accurate drift and temperature.  It would be something.  The fact is I have more power, like it or not.  Did I add more power to the bike?  No.  Did I relieve some of the restriction that kept the bike from making more of it's power potential.  Yep.  

Maybe this will capture what I'm talking about a little better.  I wrote this the other day over at Motorcycle-Journal.com in the M50 section. It describes how opening up the bikes power and doing mods has truly converted me to a big-time LS650 fan.  (Warning- if you only like the LS650 stock then don't read on.  You'll be offended.  You've been warned so don't get ill at me for my opinions if you keep reading.)

"In some ways I like it better than the Hellcat (M50). In other ways vice versa. When I sold the Hellcat it had Cobra drag pipes, DIY custom intake and fuel processor, all tuned through weeks of tweaking. It had some serious get up and go. My modded S40 would outrun the Hellcat up to about 65mph but the Hellcat would catch up and pull away by 80mph. Really strong crosswinds are hell compared to the Hellcat with it giving up 200+ pounds. You can also forget about hauling a passenger for more than 15 minutes. In town and on the country back roads, though, my modded S40 is so dang fun to ride. When I first inherited it from the wife, I had no respect for the bike. Absolutely none. To me it was just a notch above a scooter. It was a cramped, underpowered ride wrapped in outdated styling. It was okay for the wife but surely not good enough for me after having spent 20 years on much more bigger, powerful, gloriously styled cruisers. (Yep,  I was one of "those" guys that we all hate!)  I certainly had no intentions of using it as a frequent ride. I also did not know what the S40 could become in the hands of a serious modder. Now I make excuses to go ride. To me, the S40 is boring as hell stock, both visually and performance-wise. But once I understood all the ways Suzuki choked the power on the bike to keep it marketable to countries with graduated motorcycle licenses/power limits and to meet progressively stricter emissions requirements without actually replacing/redesigning parts, I got busy modding. Remember that 400cc M50 (M25) I posted about last year for the European/Asian markets? Imagine if Suzuki, instead of making the 400cc M25, took the 800cc M50, choked the intake, reduced air filter size, reduced FI injector size, choked the exhaust and programmed the ECU all to get the bike down to the levels of the 400cc bike to make it marketable overseas. Then imagine getting a hold of one of those, reversing those changes and then improving them even more. That's the kind of night and day difference I'm talking about. It becomes a totally different bike. When we do the Alabama-Georgia ride, I'd love for some of you to ride it. If you love modding, it's a hard bike to beat with the low cost being just gravy. Everything is metal. Everything is easy to get to and work on. Whereas at first I giggled at the thought of it being a serious bike for me, now nothing could separate me from it.  I spent time recently on a '08 Honda VTX 1800, '06 V-Star 1100 and a '07 V-Star 650. Well, let's just say I've gotten spoiled by the modded thumper's speed, agility, low weight, comfort and roominess. Even the VTX felt more cramped than my bike in it's current form. Those bikes simply felt slow and bulky in comparison. I've gotten used to a cruiser that hauls when the throttle is twisted. If I come across a good deal on another M50 I'll snap it up in a heartbeat. Why? Cause the M50, in my opinion, is the absolute perfect, off-the-showroom-floor blend of cruiser style and performance. But it would have to share space in the garage with the thumper, not instead of."

This was the infamous Hellcat with the custom, hand made, one-of-a-kind hi flow intake.


Now, let me go get some popcorn real quick before someone replies back!

Something else to bear in mind is that the airflow on an engine on which there is a single carburetor per cylinder is extremely pulsatile. For about 3/4 of the engine cycle there is no airflow. Airflow begins at (approximately) intake valve opening, increases as the piston drops through about mid-stroke, then decreases until intake valve closing. This has effects all through the intake system, in that filter pressure drop changes with rate of flow; carburetor vacuum changes with rate of flow; and fuel delivery and mixture probably change as well. Depending on valve overlap, exhaust system reflections, and engine speed, there may even be brief intervals of reverse flow in the intake system (usually worse on piston-port-controlled two-strokes). In the case of the Savage/S40 there is also an air line from the cylinder head (the crankcase breather) with a pulsating airflow entering the airbox behind the filter. The whole system is actually fairly complex.

Dang right!  At least it'll sound faster!  

Hey, wait a minute... now that I've thought about it- I want my money back!  Jets, spacers, pod filter, K&N filter, exhaust, synthetic oil... your revelations have shown me that all of it is money and time wasted.  Crap!  It all makes my bike lose power and performance.  This just ain't cool.  Not one bit cool.  Dang it!

I thought all those goodies weren't engineered into the LS650 because Suzuki was targeting the market with a simple, narrow, lightweight, low cost, single-cylinder motorcycle.

They might be republicans they started a war with us ,that they couldn't finish,Doesn't that sound just like a republican.

Well I sure wish those engineers would have paid attention to your wisdom and applied some of those cost-free measures so we wouldn't have to fix the bikes after the purchase.   You are the rarity here for not needing to change anything about your carb.  Or have you?


I can see it now.  It’s Friday about 3:45 in the afternoon.  A three day weekend awaits them.  Bossman Katsumi walks into the tiny, cramped R&D lab.  He looks around with his usual look of disgust.  Over in the corner, Shin, leaning against a table, quickly hides his bag of chocolate-covered Wong Dongs underneath an Eliminator 250 gas tank laying behind him and promptly wipes his hands on the front of his coveralls.  Bossman Katsumi, as usual, starts to bark out orders. "Shin, Takao, Hiroshi... you no go home til cawbeweta finish.”  The Bossman turns and walks out, slamming the rickety door behind him.  "Sh*t", barks an exasperated Shin.  "Wife and I go vacation when I get home.”  Takao reaches up with his greasy hand and pushes his thick glasses up on his nose but they quickly slip right back down to their usual position.  Takao gets up out of his chair, takes a moment to stretch, being careful not to aggravate his sciatica, then waddles over to the counter to join Shin and Hiroshi.  In frustrated silence, they all stare blankly at the paperwork.  More specifically, their gazes are fixed upon a single line which awaits ink.  All three of them realize that the only thing that stands between them and a three day weekend is a little bit of ink.  Just a couple of written numbers will grant them their freedom.  Typed letters preceding this little line, this source or their collective frustration, form the two words "Pilot Jet".  Takao picks up the paperwork, disrupting the gazes of his colleagues.  Takao scans the form for a second and turns to look at Shin and Hiroshi and says, "I tink we use 60 piwot jet."  Immediately Shin shakes his head.  "No, no",  Shin says, "60 piwot jet cost 64 yen.  Misaki say cost too much.”  Takao lets out a sigh of exasperation.  "But 60 piwot better for motowcycle", replies Takao.  Hiroshi turns to reach for his Asahi Premium Malt when a bag, sitting across the table next to the remnants of what had been Takao’s McSushi sandwich, catches his eye.  "Hey, we use dose piwot jets", exclaims an excited Hiroshi, pointing to the newly discovered bag.  "Dat way it not cost more.”  Hiroshi’s demeanor changes as a look of satisfaction falls upon his pudgy, middle-aged face.  With a look of hope suddenly alive in Shin's eyes, he eagerly leans over and picks the bag up.  A moment after examining the bag his optimism appears to quickly drain from his face.  "No", says Shin with a defeated voice.  "Dees for Eliminator 250.  Not big enough".  Takao turns to look at Shin.  "So?” asks Takao, the rhetorical certainly not lost on the others.  "It fit.  Dose Americans change out anyway."  All three fill the room with jubilant laughter.  A victorious ambience rapidly fills the musty room. Takao pulls his pen out of his pocket in a sweeping, purposeful motion, as though it where a Samurai sword being gallantly raised by the hand of the battle victor.  With growing anticipation of tomorrow’s Dragon’s Day parade he eagerly fills in the blank line.  "All finish", Takao announces, only to discover he is alone.  He realizes then that Shin and Hiroshi had apparently run out of the room already.  "Ha, ha", Takao says to himself.  "Dose too are cwazy!".