Thoughts on 2003 ZX6R (636)?

[daveyg]

I'm looking at picking up an 03 636 with 18k miles on the clock, front fairings gone, has just 2 tiny headlights straddling the intake snorkel (I think that part looks like sh!t, but I've got a lead on a 9" round HID Harley headlight and bucket setup, as well as just hacking off the snorkel. My main inquiry is if any of you guys know of any issues to watch out for that might break the bank. Thanks!

[MaximPhil]

Hi Daveyg,
While I know nothing about the ZX6R specifically I would caution messing with the intake snorkel until you have done some research. Modern bikes have some highly engineered intake/airbox set up and you might upset the performance in a negative way.
Phil

[motoman]

Hi Daveyg,
While I know nothing about the ZX6R specifically I would caution messing with the intake snorkel until you have done some research. Modern bikes have some highly engineered intake/airbox set up and you might upset the performance in a negative way.
Phil

SAme is the case with our ole' XS11's............but regularly gets ignored.

[CRXSi90]

I might remember something bout the starter clutch giving trouble, but other than that I don't have anything constructive to say.

[Bonz]

The 636 is a good bike from the perspective of a middle weight sports bike. The larger engine displacement vs. the 600's makes a nice difference in real world riding, and as I reacall the bike has proportions that make it feel roomy and spread out relative to the other bikes in it's class.

The 636 was such a good idea, after Kawasaki nixed it during the down economy, Kawasaki brought it back in the last year, said "screw it" to the conventional 599 cc engine size, and the 636 is one of the top rated bikes in it's category.

It may well use RAM air, as many Kawasaki sport-type bikes do, so it's probably not running near what it should/could with a naked front end.

As for our XS1100's and the air snorkel, that does not have a negative effect on performance in my opinion, just flows more air. By the time the air gets through the airbox, through the stacks in the airbox and into the carbs, the snorkel is long forgotten in terms of performance.

I have an 80SG that is full stock including airbox, snorkel, etc and I also have an 80G with snorkel removed, airbox drilled. BOTH are strong runners and can't tell them apart performance wise.

[motoman]

The 636 is a good bike from the perspective of a middle weight sports bike. The larger engine displacement vs. the 600's makes a nice difference in real world riding, and as I reacall the bike has proportions that make it feel roomy and spread out relative to the other bikes in it's class.

The 636 was such a good idea, after Kawasaki nixed it during the down economy, Kawasaki brought it back in the last year, said "screw it" to the conventional 599 cc engine size, and the 636 is one of the top rated bikes in it's category.

It may well use RAM air, as many Kawasaki sport-type bikes do, so it's probably not running near what it should/could with a naked front end.

As for our XS1100's and the air snorkel, that does not have a negative effect on performance in my opinion, just flows more air. By the time the air gets through the airbox, through the stacks in the airbox and into the carbs, the snorkel is long forgotten in terms of performance.

I have an 80SG that is full stock including airbox, snorkel, etc and I also have an 80G with snorkel removed, airbox drilled. BOTH are strong runners and can't tell them apart performance wise.

Likely not much difference performance wise, but referring to velocity effect from snorkel, that continues for final intake thru carb intake, even tho slightly reduced. Same principal as hydralics and flow Howard, just air instead of oil.

[Bonz]

What if the snorkel is just where it makes the most sense to place it, by virtue of carbs being on back of the engine, airbox behind the carbs, snorkel connects to the airbox... To be clear, I am talking about conventional intake systems, not ram air or otherwise.

Man, all you guys have been buying into the myth of studious Japanese men in white coats slide-ruling this stuff when they really just looked at it and said "hmmm... stick it there Joe, and let's have saki with dinner".

Opening up one end of the combustion system should be met with a commensurate opening of the other end, and since the XS is pretty much as stout as it can be from the factory, unless the exhaust can be opened up (and it has been shown aftermarket systems don't do much if anyting for add'l performance) anything on the intake end is pretty much just for show and very little go.

[motoman]

What if the snorkel is just where it makes the most sense to place it, by virtue of carbs being on back of the engine, airbox behind the carbs, snorkel connects to the airbox... To be clear, I am talking about conventional intake systems, not ram air or otherwise.

Man, all you guys have been buying into the myth of studious Japanese men in white coats slide-ruling this stuff when they really just looked at it and said "hmmm... stick it there Joe, and let's have saki with dinner".

Opening up one end of the combustion system should be met with a commensurate opening of the other end, and since the XS is pretty much as stout as it can be from the factory, unless the exhaust can be opened up (and it has been shown aftermarket systems don't do much if anyting for add'l performance) anything on the intake end is pretty much just for show and very little go.

Actually, because of limited space that bikes have in order to keep things compact and non intruding as possible, there IS alot of design engineering that went into the intake on these and other bikes that utilize vacuum slide carbs. The intake design has EVERTHING to do with the correct and SMOOTH operation of bike thru ALL rpm ranges, and maximizing the applied power in all rpm ranges. The exhaust IS internally more comlplicated than meets the eye, specially down where the two go into one. CZ's cross-cutting the stock exhaust into sections verify this. Ken Talbot is another that can verify the stock airbox and stock exhaust are an INTENTIONAL design for smooth CORRECT operation of intake and an exhaust system that smoothly DRAWS the exiting burnt gases. So, with the men in white coats success, they very well could of shared saki with dinner. When this scoot twisted out a 11.79 quarter mile time with its measly 95 crank horsepower, they may have just skipped the dinner though. Unfortunately, many, when they find these bikes, the airbox is gone and the stock exhaust looks like a sieve, leading them to no other option in many cases than pods and an aftermarket 4into one exhaust, which BTW was designed for WOT. This be the reason many have to do the jetting dance and such to get decent SMOOTH operation at the lower and mid rpm ranges. With the stock intake and stock exhaust, you can have your cake and eat it too so to speak, and this has proved out hundreds if not thousands of times. Only thing I see that would improve utilizing the overall stock design, including cam profiles and combustin chamber design would be a cold outside air ram-air induction.

[Bonz]

I love keeping you on top of this stuff, motoman! Your explanations of function and passion for the XS1100 condition are without peer!

As for the 11.79 second 1/4 mile, the XS1100 is geared shorter than a midget in the 4th of July Parade. Especially as you pointed out, with only 95 crank horsepower and I'm going to guess maybe 85 to the rear wheel on the best day, more like 80 hp to the wheel is probably realistic.

I would say the XS1100, and other bikes of it's time, were set out into the world pretty well dressed for success, if you will, in the power department. Not much more can be wrung out of them.

[motoman]

I love keeping you on top of this stuff, motoman! Your explanations of function and passion for the XS1100 condition are without peer!

As for the 11.79 second 1/4 mile, the XS1100 is geared shorter than a midget in the 4th of July Parade. Especially as you pointed out, with only 95 crank horsepower and I'm going to guess maybe 85 to the rear wheel on the best day, more like 80 hp to the wheel is probably realistic.

I would say the XS1100, and other bikes of it's time, were set out into the world pretty well dressed for success, if you will, in the power department. Not much more can be wrung out of them.

Without a doubt the '11' could of easily ran quicker times in the quarter with an even lower final gear ratio getting it some even quicker 60ft. times, which pretty much is 'where it's at' runnin' the 1320. To pull hard on the other end would require some more ponies. As it is, with the 17" on the rear of my Venturer, 4th gear unfortunately had to come some 100+-yrds. before the finish which dropped its pull on that end. Of course, the 'barn door' on the front with a 25in. shield was of no help either. The naked Special having the 16" rear would of pulled that other end better in fourth no doubt. Still, some high 13's and low-low 14's were respectful here at 5000ft. elev. in full dress form without 'cowboying' it real hard off the starts, plus midway thru third, clutch would turn loose a bit. New Barrnet pressure plate springs would cure that, but hey, it's a tourer, not a straight line terror like your vintage V-Max. Still fun when occassionally challenged with other touring models out on LD rides, and it will still drag most any of newer full dress touring class bikes. Was way more fun 30+yrs. ago touring knowing there was nothing out there that could touch it.......not even with two-up. Trust me, many tried, taking advantage of the two-up.....NONE succeded, ever. The E model Suzy came the closest, but no cigar, thanks to the shorter than a midget geared final drive.