a few questions about the SG, and the SF...

[ERM83]

Okay...so, i posted before about the SG popping a bit when idling. didn't know you needed a special tool to adjust it, and the manual states that you don't have to mess with it?? could it be the cam chain tensioner?! my wires/coils/plugs are fine...not sure what to do.

on to the SF:

this one definitely is a winter project, and needs a new head. however, there's a HUGE, awesome community of vintage riders here in louisville. everyone goes to "vintage days" at the mid-ohio track every year. i think i wanna deck the SF out, and enter the original superbike heavyweight race, because i'm a crazy person. i've been riding all of my life, and (there's MAYBE 3 things in my life i'll say this about) i'm good at it. i suck at pretty much everything else, haha. that being said: i know my way around these now, thanks to you guys. however, i need the guru's on this website's advice on some general mods...what's the best way to go about making it lighter/faster?? if i can make this happen, i'm gonna need an XS11.com patch/sticker!

[ViperRon]

This bike is built heavy in many areas some to support others. Pretty much when you start lightening the bike you need to have a planed path and it will take away from the originality some. An Important thing to keep in mind is several things are dependent on others. For instance the wheels are heavy but built that way to handle the weight of the bike and they have reinforcement built into them so trimming them down some times requires real thought. Brakes can be upgraded to newer systems reduce weight and get better performance by going with more modern rotors with less weight. some side covers could be replaced with plastic cut on CNC machine. Some have swapped out the front fork system and you can search names here. I do beg that if you have a good frame you do not hack it up they are getting more and more rare. Exhaust there are a number of different solutions to reduce weight. Mac pipes with the flare tips are much lighter but the tapered tips and side mufflers are heavy. Center stand case protector guards front fender will all lighten it but the front fender actually is a stabilizer for the front forks and if you dump it once the case guards pay for them self. Like I said make a plan talk here with others before you start.

[donebysunday]

Agreed !
Take off what you like/don't like but leave it so you can go back, (most things you take off). In some cases you can add lightness, exhaust (4-1), brakes, lighter calipers and rotors. Things like this are or can be upgrades you will want to keep even if you go back to stock. Is the lighter bike worth the added cost ? Only you can decide !

This bike is built heavy in many areas some to support others. Pretty much when you start lightening the bike you need to have a planed path and it will take away from the originality some. An Important thing to keep in mind is several things are dependent on others. For instance the wheels are heavy but built that way to handle the weight of the bike and they have reinforcement built into them so trimming them down some times requires real thought. Brakes can be upgraded to newer systems reduce weight and get better performance by going with more modern rotors with less weight. some side covers could be replaced with plastic cut on CNC machine. Some have swapped out the front fork system and you can search names here. I do beg that if you have a good frame you do not hack it up they are getting more and more rare. Exhaust there are a number of different solutions to reduce weight. Mac pipes with the flare tips are much lighter but the tapered tips and side mufflers are heavy. Center stand case protector guards front fender will all lighten it but the front fender actually is a stabilizer for the front forks and if you dump it once the case guards pay for them self. Like I said make a plan talk here with others before you start.

[jetmechmarty]

You can lose fifteen pounds of brakes. Even better that, it's unsprung weight.

This rotor weighs less than three pounds. Call Michael Morse at 650Central.com or maybe Chacal at XJBikes.

Replace the front fender with a plastic one. There goes more unsprung weight. I think you lose a couple of pounds by switching to XJ wheels as well.

Replace the gauges with one of those little Acewell units.

Don't mess with the frame. It's good and strong. Leave it that way.

[ERM83]

you guys are AWESOME!

Oh, i had NO intention on messing with the frame...no way. my SG is staying as close to original as possible. the SF has already had some stuff messed with, so i figured that would be the one i'd mod and try to race. the SG is WAY too close to original to screw around on...not doing that!

that being said...IIRC, putting on an aftermarket exhaust actually makes you LOSE horsepower?? I know the OEM's are hard to find and EXPENSIVE...both my bikes came with a mac 4-2 tapered-end. would i get more out of it with a 4 to 1?? again, thanks for the help...i'll be posting about progress / asking for your all's wisdom every so often! gonna look up suspension mods...brakes, i actually have some ideas and leads on. thanks for the rotor lead, by the way!!! i didn't realize how freakin' heavy those calipers were!! did a rebuild on the front calipers, and a pad change on the rear over the weekend on the SG.

OH...CARBS. what's the best plan of action there?? i put the sf carbs on the sg, so i definitely need another set. i'm going to look up some equivalents, but any input is encouraged and appreciated! i've never decked one of these out for high performance...just need to know the ticks that these bikes have. also, money isn't an issue...i'm not married, no kids, low bills, etc. musical equipment and motorcycles are what i spend my spare loot on, haha!

[TopCatGr58]

Ooooh....Deep Pockets!

Hey there Erm,

The OEM pipes were designed to provide the best ALL AROUND performance and power, but aftermarket pipes won't necessarily make you loose power provided you properly tune/jet the carbs to compensate for the changes in air flow. The 4-1's MOVE the powerband further up in the rpm range, the XS's engine comes alive at around 3500 rpm anyways, but 4-1's can help keep and extend the power into the 7+K rpm range....it's best NOT to take it above 8K too much due to the age/wear of the valve springs and possible tendency to float valves/hit pistons!

Aside from OEM carbs, folks have put on newer GXSR carbs which have reported providing smoother running, more power, better fuel economy as well as easier tuning and available parts. They don't have the metered port for the vac. advance, but it's been shown that the vac. adv. is more for trying to get better fuel economy and throttle transition response, but running without it will not cause any actual loss of power.

So...on this subject, Pod filters vs. OEM airbox....again, no improvement in horsepower by itself, but you have to think that with increased outflow/exhaust, increasing the ease of inflow of the F/A mixture couldn't hurt. BUT Yamaha's OEM airbox has built in VELOCITY stacks to help straighten out and smooth out the air coming into the carbs, as well as reducing turbulence, and folks reported lots of problems with tuning with pods in the beginning. BUT we found that it was more due to the cheap Pods that had a prominent mounting lip that interfered with the inlet bell ports. Also, folks were getting the Cheap/Generic K&L Pilot jets that are metered differently/much richer than Genuine Mikuni, and that also contributed to the trouble tuning. There are tech tips that show how to make the velocity stack type mounts to put Pods on so you get the ease of R&R of the carbs without the airbox, but also the benefit of the velocity stack inlet design.

In your previous post you said that the RACE was for "Original Heavy Weight Superbikes", so what are the restrictions if any, like does it have to be OEM equipment/parts, or are you allowed MODS???

Replacing the front calipers on your SF will be problematic due to the design of the single swivel mount bolt. Here's a thread that shows the trouble it is to MOD the special front brakes. http://www.xs11.com/forum/showthread...ial+fork+brake

A way to get modern calipers is either to put on a different modern front end, OR, swap the special forks for standards which are easier to MOD with an adapter plate, again see the tech tips/mods for this. If you get Standard Forks, but keep the Special TT's, it can reduce the trail a little to make the steering a little lighter/quicker....a trick the sidecar guys did/do with their Standards to make steering easier with the sidecar rig. But if you're aiming for top speed, then you may want to keep the standard TT's with the forks, to keep the stock trail for better high speed stability.

Other way to loose weight is to drop the centerstand. Also, since it's an SF, it should still have the kick start shaft, so you could remove the electrical starter to loose a few more pounds, and just kick start it!?

T.C.

[ERM83]

ok...after doing some research, i'm still having to ask a couple of questions.

still don't know what's going on with the backfiring issue with the SG, and wondering if it's the CCT, or i need to get the tool to set the timing??

on the SF: looked into the carbs. what year of GSXR carbs are the best/most compatible?? i plan on getting new carb boots for both bikes (SG is staying close to stock, so this is more about the SF), so the diameter of carbs isn't an issue...i just want to know what would work best with these beasts.

i'm probably going to redo the front end, as well as a shock mod on the rear. OH...shaft to chain mod. need to do that...???

[ERM83]

Is there anyone who would bend/make an exhaust similar to the OEM's, or am i ok with the 4-2 MAC?? i have the carbs jetted correctly...i just remember making a post, and TC saying that aftermarket exhausts IMMEDIATELY reduce a bit of horsepower. also, VALVE SPRINGS....need to look into that. if i'm racing the SF, gonna need those. that bike is mostly apart (top end...head is off), so i'd rather get springs for high-performance while i'm in there.

[TopCatGr58]

Hey ERM,

I did NOT say you would have an immediate loss of power with aftermarket pipes, just that changes in the flow characteristics of aftermarket pipes can require adjustments in tuning, jetting to get the most out of them vs. OEM pipes.

Keep in mind that the Macs don't pair the cylinders well like the Jardines did. The Macs put 1-2 and 3-4 together which doesn't compliment the exhaust pulses and scavenging efficiency of the engine compared to the 1-4 and 2-3 pairing that the Jardines do.

But for "racing", I don't know if keeping 4-2's would work just as well as 4-1's or not. I just know that the 4-1's are supposed to scavenge a bit better specifically for the upper rpm range vs. 4-2's, and so would think they would be better in a racing application if you were going to be running in the mid/upper rpm range mostly.

As to the valve springs and such, see Bonz's recent thread discussing this. Also keep in mind that the dyno results show that the XS11's max torque and HP happens around 7500 rpm, and so pushing it much beyond that doesn't necessarily mean you'll get any more power out of it, but might help keep the rpms higher when you shift up. I'm trying to remember how many rpms difference there is between the gears, like ~1k drop from 3rd to 4th, etc.. The earlier engines had hotter cams with a bit more lift IIRC, and the later engines had less lift because of larger valves providing similar flow capacity. SO I would think that the early engines would be a little more prone to float a valve at a particular rpm due to the higher lift vs. the later engines. The heads use dual springs anyways for the valves, I don't know if aftermarket new springs are available or not?

There is an old thread by a very knowledgeable member discussing ways to get more power out of the XS11 engine, but they are already pretty close to max output just in the stock configuration. What was finally learned is that to get the most increase in output, just put on an NOS system! Otherwise, you'll be throwing a whole lot of money at it for not very many more HP's!

Converting to Chain Drive is a way to get ~10% of the HP back, but then it's no longer in STOCK configuration which might disqualify you for your racing bracket??

There "were" 2 main flavors of big bore kits from Wiseco, the 1179cc and the 1196cc kits. These are made with FORGED pistons and $$. This last year or so, some Japanese company provided the 1196 kit with cast pistons for a very decent price of $150.00 for pistons, rings, wristpins, head gasket, you just provide the boring and valve work. But these kits are mostly to help freshen up an OLD engine since the regular oversized parts are no longer available from Yamaha.

However, my seat of the pants sensation with my little 1179 kit seemed stronger than my OEM configuration....but I had a~10 year break between riding my OEM and then my rebuild. YMMV.

T.C.

[ERM83]

thank you, T.C.!

Hey, sorry...i didn't mean to misquote you! so, 4-1 it is. i'm gonna try to do some research on the GXSR carbs in a second. i have off today, and all i need to do today is clean up (preparing to move next week!), so the rest of the off-day's use is dedicated to my two favorites: MOTORCYCLES, AND MUSIC.

I think my main concern is that i DON'T want to float the valves. i think i remember hearing that the 80' cams are the first without all the lift?? can i use an 80' head / cams?? because of all of the help from you guys on here, i can whip around these bikes pretty easily mechanically...now i just need to know some technical things...compatibility, etc. i'll be sure to check out that performance thread as well!!

Eric M

[motoman]

Hey, sorry...i didn't mean to misquote you! so, 4-1 it is. i'm gonna try to do some research on the GXSR carbs in a second. i have off today, and all i need to do today is clean up (preparing to move next week!), so the rest of the off-day's use is dedicated to my two favorites: MOTORCYCLES, AND MUSIC.

I think my main concern is that i DON'T want to float the valves. i think i remember hearing that the 80' cams are the first without all the lift?? can i use an 80' head / cams?? because of all of the help from you guys on here, i can whip around these bikes pretty easily mechanically...now i just need to know some technical things...compatibility, etc. i'll be sure to check out that performance thread as well!!

Eric M

Not an issue as I've bounced my bikes tach off 10K several times over the past decades with a missed speed-shift.

[ERM83]

Not an issue as I've bounced my bikes tach off 10K several times over the past decades with a missed speed-shift.

HOLY S#&@! That makes me anxious just reading this, haha!

So in two weeks (moving next week, so can't dedicate the time/money), i'm going to start working on the soon-to-be mutt. i'll make a separate thread for that as well. I'm making a list of what i need, and a HUGE thing is the GXSR carbs, as i don't have any carbs for the SF. need to know and look into that.

still need advice on my backfiring issue on the SG. Do I need the tool dedicated for the timing?? also, i JUST noticed that i'm getting a bit of gas coming out of the intake of carb #1. did a boot/oil check...the carbs are synched. could it be the CCT?! it runs well, but the ocd in me is wanting that slight pop GONE. HELP ME OUT HERE!

[DiverRay]

You do NOT need a dedicated tool for timing! What you need to do is pull all 4 spark plugs, rotate the crank close to TDC mark, stick a new wood pencil into the #1 plug hole, and SLOWLY rotate as you watch the pencil. When it stops moving out, you should be at TDC. If you are, your good so far. If not, pull the pencil, rotate the crank about 345 degrees and do the pencil trick again, in case your off on the TDC.
If it still will not line up, make sure the pencil shows the piston at TDC, loosen the screw holding the timing pointer, and line it up to TDC. Pull pencil, rotate 345 and check two more times to verify you are at TDC with the pointer when the piston is at TDC.
Once there, get a timing light, put the plugs back in, and check the timing per the factory manual to verify it's in time.
The OTHER thing it may be is the advance unit. You will have to pull the center allen bolt and remove the timing plate to get to it, but if you don't know how long it's been since it was cleaned and lubed, it's a must.

[red bandit]

[QUOTE=ERM83;492777] a HUGE thing is the GXSR carbs

GSXR don't line up with the intake manifolds. The spacing is off.
I have a set of 2000 ZRX carbs off an 1100 and the spacing is perfect. I had to go up one size on the pilot jets and you have to fabricate something for the throttle cable/carb hook up. They have a slightly bigger bore and run great. YMMV

[ERM83]

You do NOT need a dedicated tool for timing! What you need to do is pull all 4 spark plugs, rotate the crank close to TDC mark, stick a new wood pencil into the #1 plug hole, and SLOWLY rotate as you watch the pencil. When it stops moving out, you should be at TDC. If you are, your good so far. If not, pull the pencil, rotate the crank about 345 degrees and do the pencil trick again, in case your off on the TDC.
If it still will not line up, make sure the pencil shows the piston at TDC, loosen the screw holding the timing pointer, and line it up to TDC. Pull pencil, rotate 345 and check two more times to verify you are at TDC with the pointer when the piston is at TDC.
Once there, get a timing light, put the plugs back in, and check the timing per the factory manual to verify it's in time.
The OTHER thing it may be is the advance unit. You will have to pull the center allen bolt and remove the timing plate to get to it, but if you don't know how long it's been since it was cleaned and lubed, it's a must.

THANK YOU RAY, AS ALWAYS! This popping has been driving me NUTS, and seriously, I've changed the plugs twice now out of paranoia...and they look completely fine. HOWEVER, EVERYTHING on the left side of this bike has been hell to maintain...meaning, it very well could be the advance unit. the left side of the exhaust looks worse, the left-front caliper was worse, etc. I think that was the side exposed to the elements while in the garage it was in. had to re-tap spark plug #1. no loss of compression there as well.

I DO want to note that I just noticed a slight (VERY SLIGHT, at that) gas drip out of carb #1...nothing crazy, but still...maybe float levels as well?? coming out of the intake side. took the pod off, and it had a bit of gas in the inside of the intake part of the carb...below the air-jet. no spitting or anything, though.