Hi all,
I am new to the forum and am looking at buying a gs500 for trackdays . I will be using the bike on long tracks and gokart/supermoto tracks(They are a lot cheaper per day and you get a lot of track time). I know this probably sounds wierd to you guys, but I like both kinds of riding, but can't afford 2 track bikes. I will be changing the gearing and bars for each track and the bike will have lots of crash protection(I will crash).
My questions are mainly to do with tuning the motor. Has anyone tried reducing the base circle of the cams to increase lift and duration of the cams. This is a cheap way of getting a wilder set of cams and know it has been done with good results on other bikes? Anyone know how much I can skim the head safely, to increase compresion.
I will flow the head myself and make a replacement exhaust system. I will also install a APE manual cam chain tensioner as an automatic one can let the cam chain slip under hard use(and mine will be used hard).
I have read about the K & N "lunchbox" air filter housing. I'm not sure what this is. I assume it's a better shaped air box. Is it worth having, along with the K&N filter? I will also make up an ignition advancer from the instructions on this site(great site by the way).
Has anyone got other suggestions?
The bike will get a serious weight loss program and a whole host of other chassis mods(I will post some pics of the donor bike(when I get it) and also pic's as it progress's). I have a Maxton race CBR600 front end and will be getting a GSX600f(Katana in the US) shock or symilar to prop up the back end. The finished bike will have a semi-flat tracker look to it when finished.
Anyone got any other Ideas?
Thanks in advance
Andy
Hello there and welcome to gstwins! Your project sounds really cool and you seem to have alot of previous experience with sqeezing every last hp and lb-ft out of internal combustion engines. I haven't heard much about reducing the base circle of the cams on here, but I'm sure some of the heavy hitters in the community will chime in on that soon enough. And you're right on with the suspension, everyone who races replaces it with something else and the Katana shock seems to be a very popular option because it is so easy to swap out and it pretty darn good. I can help you with the lunchbox though, here is a link to what people are talking about at Bikebandit.com, I'm sure you can find a cheaper one if you poke around the FS/FT forum or ebay.
lunchbox link (http://www.bikebandit.com/k-n-universal-dual-flange-oval-air-filter-rubber-centered?mg=3609&t=1&td=1)
Other than that, what type of tires do you plan on getting? I've got Metzelers but a very popular option seems to be the Bridgestone BT-090's, and I know someone on the forum is selling a set here is the link to that thread: ineedanap's thread (http://gstwins.com/gsboard/index.php?topic=50243.0)
Have fun!
BT090 are the past.. BT003 is now the way to go.
Quote from: Bluehaze on October 06, 2009, 05:09:35 PM
BT090 are the past.. BT003 is now the way to go.
There is no BT003 for our bikes. There is a BT003RS, though, but I've never tried it.
I might be old school but I liked my 090s. Don't need tire warmers. Stick like glue. Can get a couple hundred laps out of them. I might even buy another set for my SV.
Bluehaze, how'd you like the BT090's when you tried them?
(http://www.motorcycle-usa.com/photogallerys/bridgestone-battlax-line-up-chart.jpg)
Quote from: andyroach on October 06, 2009, 03:40:18 PM
The bike will get a serious weight loss program and a whole host of other chassis mods(I will post some pics of the donor bike(when I get it) and also pic's as it progress's). I have a Maxton race CBR600 front end and will be getting a GSX600f(Katana in the US) shock or symilar to prop up the back end. The finished bike will have a semi-flat tracker look to it when finished.
Anyone got any other Ideas?
Thanks in advance
Andy
Sounds awesome. I had lots of fun with my GS. Ended up parting it out last month since my wife "made me" buy something faster. It was fun as heck while it lasted and I passed my share of ducatis/gsxrs/cbrs and the rest in the turns.
If I were to add my 2 cents...and remember it's just my opinion...I'd skip the motor work other than the lunchbox/exhaust/jetting/advancer. I started going that route and there's not alot of return for your money there. Our easy "big bore" high compression wiseco and vance/hines pistons have either been changed or discontinued. You can have megacycle make you big cams out of your small ones, though.
Katana is good for what it is (cheap shock with a stiff spring) but not very fun on the track. The rebound and compression are a mess and nonadjustable. You might want to consider having Works or Hagon (or if you have more money than me ohlins or penske) make you a custom shock. It will completely transform the ride.
Represent the GS well...Give em heck out there!
Quote from: ineedanap on October 06, 2009, 05:19:17 PM
There is no BT003 for our bikes. There is a BT003RS, though, but I've never tried it.
Bluehaze, how'd you like the BT090's when you tried them?
You forget quickly... check out the thread for tire for track day.. we went back and forth about 090 and 003RS.
Quote from: Bluehaze on October 06, 2009, 05:55:01 PM
Quote from: ineedanap on October 06, 2009, 05:19:17 PM
There is no BT003 for our bikes. There is a BT003RS, though, but I've never tried it.
Bluehaze, how'd you like the BT090's when you tried them?
You forget quickly... check out the thread for tire for track day.. we went back and forth about 090 and 003RS.
I didn't forget...I asked YOU how YOU liked the 090.
no.. they sent me the wrong version. thx to your tip regarding tl and tt. stupid motorcycle supersport. and from 180 cost of 003rs to 270 of bt090. i opted for 003.
Quote from: Bluehaze on October 06, 2009, 06:02:02 PM
no.. they sent me the wrong version. thx to your tip regarding tl and tt. stupid motorcycle supersport. and from 180 cost of 003rs to 270 of bt090. i opted for 003.
I know...I meant it jokingly since you had that fiasco with the 090s that worked out in your favor!
Quote from: nakedGS on October 06, 2009, 04:09:06 PM
Hello there and welcome to gstwins! Your project sounds really cool and you seem to have alot of previous experience with sqeezing every last hp and lb-ft out of internal combustion engines. I haven't heard much about reducing the base circle of the cams on here, but I'm sure some of the heavy hitters in the community will chime in on that soon enough. And you're right on with the suspension, everyone who races replaces it with something else and the Katana shock seems to be a very popular option because it is so easy to swap out and it pretty darn good. I can help you with the lunchbox though, here is a link to what people are talking about at Bikebandit.com, I'm sure you can find a cheaper one if you poke around the FS/FT forum or ebay.
lunchbox link (http://www.bikebandit.com/k-n-universal-dual-flange-oval-air-filter-rubber-centered?mg=3609&t=1&td=1)
Other than that, what type of tires do you plan on getting? I've got Metzelers but a very popular option seems to be the Bridgestone BT-090's, and I know someone on the forum is selling a set here is the link to that thread: ineedanap's thread (http://gstwins.com/gsboard/index.php?topic=50243.0)
Have fun!
Thanks for the K&N link. At least I now know that it is a tuning mod and not a motorcycle mounted sandwich storage system.
I have a set of Supermoto spoked wheels that I will be fitting(probably not immmediatly) and will run slicks, as it will only be used on the track.
Andy
Quote from: ineedanap on October 06, 2009, 05:50:18 PM
Quote from: andyroach on October 06, 2009, 03:40:18 PM
The bike will get a serious weight loss program and a whole host of other chassis mods(I will post some pics of the donor bike(when I get it) and also pic's as it progress's). I have a Maxton race CBR600 front end and will be getting a GSX600f(Katana in the US) shock or symilar to prop up the back end. The finished bike will have a semi-flat tracker look to it when finished.
Anyone got any other Ideas?
Thanks in advance
Andy
Sounds awesome. I had lots of fun with my GS. Ended up parting it out last month since my wife "made me" buy something faster. It was fun as heck while it lasted and I passed my share of ducatis/gsxrs/cbrs and the rest in the turns.
If I were to add my 2 cents...and remember it's just my opinion...I'd skip the motor work other than the lunchbox/exhaust/jetting/advancer. I started going that route and there's not alot of return for your money there. Our easy "big bore" high compression wiseco and vance/hines pistons have either been changed or discontinued. You can have megacycle make you big cams out of your small ones, though.
Katana is good for what it is (cheap shock with a stiff spring) but not very fun on the track. The rebound and compression are a mess and nonadjustable. You might want to consider having Works or Hagon (or if you have more money than me ohlins or penske) make you a custom shock. It will completely transform the ride.
Represent the GS well...Give em heck out there!
I really enjoy the engine tuning side, as well as the chassis upgrades and am really keen on seeing what the ports are like. If they are like the other Jap bikes I have fiddled with, they are usually a mess of casting crap and valve guides that almost extend in to the combustion chamber and normally the port is too big on the outlet.
One of the reasons for choosing the gs is because I can pick an early 90's one up for about 400 Euros(I am English, but live in Southern Spain)which is about 600 $. So if I chicken it up or blow it up I can just pick up another bike and use that for spares. I have a race Guzzi that I built and will post a picture when I work out how. But if I do some real radical engine work and it lets go, It will cost a couple of thousand Euros just to get back on the track.
I had thought about getting an R6 shock and getting Maxton to revalve/spring it and after what you said about the Kat shock, I think I will price it up.
Cheers
Andy
look into a early 90's gsxr shock, I have one and love it, adjustable compression and rebound, with a remote reservoir.
i got mine on ebay for around $50.
Quote from: jeremy_nash on October 07, 2009, 05:44:19 AM
look into a early 90's gsxr shock, I have one and love it, adjustable compression and rebound, with a remote reservoir.
i got mine on ebay for around $50.
Which model GSXR? and is it the 750 or the 1100. The only reservations I have about this is that the GSXR shock will be at least 15 years old and not exactly in the first flushs of it's youth. I am following the thread about the R6 shock on this forum and hope to work out if the shock is too soft or too hard and if it alters the ride hight. Once I get this info and actually buy a bike, I can then make a new linkage for the shock and hopefully get the spring rate/damping correct. Once I have that done I will ask on the forum if anyone else is interested in one before I have a batch made( I have a tame engineer that will make batches of pieces for me as long as I supply a template.)
mine is from a 93 gsxr 750 that is true, it being 16 years old, may not be in the best of shape, but if your going to have a shock rebuilt, might as well start out with nice features. I had 2 inch lowering links on my bike when I put the shock on, and now it sits back at stock height, so I would say it raises it about 2 inches
Quote from: jeremy_nash on October 07, 2009, 11:29:22 AM
mine is from a 93 gsxr 750 that is true, it being 16 years old, may not be in the best of shape, but if your going to have a shock rebuilt, might as well start out with nice features. I had 2 inch lowering links on my bike when I put the shock on, and now it sits back at stock height, so I would say it raises it about 2 inches
If I could work out the bell crank (linkage) so that the R6 shock works well in stock form, i wouldn't need the shock rebuild or resprung and suspension sophistication has come on a long way in the past 16 years. I am not knocking your idea and appreciate your input and it may become an option if cash becomes tight(or tighter). But I quite like the idea of being able to supply you guys with a bell crank that will drop in and enable you to fit a cheaper and better option than to buy a replacement new gs shock. Also I will have a nice shock for my bike.
Andy
When you say making a new linkage for the r6 shock are you saying that just so it does not hit the swingarm? I have the r6 shock and no it does not raise the bike in any way at all. It is a straight bolt on and the only issue isthe 3mm rub of the shock coil on the swingarm. took 30 minutes of slow grinding to get that out of the way.
If your linkage can make that go away at a good price..i thinkyou will get some people here to buy it if they dont want to grind.
I was thinking more along the lines of adjusting the dimensions of the 3 shock/linkage/frame mounting holes in relation to each other to make the spring/damping correct for the bike and possibly raising the back up maybe 20-30mm to speed up the steering. but could also make it clear the swing arm while I am at it.
I will try the R6 shock first to and see if it is too soft and may be change the springs in the forks (as this seems to be what a lot of people do) and once I have the shock right I will change the front end for the race CBR one that I have lying around. This is the way I like to work, change one thing at a time and get it right, before changing the next thing, other wise, if the CBR forks are too hard/soft it can make the back end feel like it isn't right.
Andy
buy mine. I am pretty sure I am going to selll it. I have .95 front fork springs and a gsxr rear shock, spare forks, spare lots of stuff. 08 petcock, rejetted, yadda yadda.
I logged on to start formatting a for sale ad.
Quote from: intergalactic on October 15, 2009, 08:31:38 PM
buy mine. I am pretty sure I am going to selll it. I have .95 front fork springs and a gsxr rear shock, spare forks, spare lots of stuff. 08 petcock, rejetted, yadda yadda.
I logged on to start formatting a for sale ad.
There is the small problem of shipping. I live in Southern Spain. The shipping and taxes would be more than I would be buying the bike for.
Nice idea though.
Best of luck with selling the bike.
To chime in on the tires: I ran a 120 (not 110) 003 on my 89 stock front rim for my last race of the year at Beaverun. The tire fit fine and it slowed the twitchiness down just a tad. The tire was a dream! I am stuck with a 090 on the rear but who cares since I am not spinning the tire up every exit. Keep us updated on what you do, especially the lightening part...
Quote from: fastedmiami on October 28, 2009, 02:14:03 PM
To chime in on the tires: I ran a 120 (not 110) 003 on my 89 stock front rim for my last race of the year at Beaverun. The tire fit fine and it slowed the twitchiness down just a tad. The tire was a dream! I am stuck with a 090 on the rear but who cares since I am not spinning the tire up every exit. Keep us updated on what you do, especially the lightening part...
BeaveRun, as in PA? I go to that track a lot!
Yes, we were there racing the first weekend in October. It's a fun little track, but I would not want to be on it on anything bigger than an sv, it's just too scary!
We're done riding for the year. It's too damn cold....and not to mention, there's no electric and we sleep in our trailer and last year in October I thought I was going to wake up w/ frostbite on my toes!!! LOL Maybe i'll see you around in the spring. If you see a trailer w/ PAsportbikes.com on the side, stop by and say hi!
Quote from: fastedmiami on October 28, 2009, 02:14:03 PM
To chime in on the tires: I ran a 120 (not 110) 003 on my 89 stock front rim for my last race of the year at Beaverun. The tire fit fine and it slowed the twitchiness down just a tad. The tire was a dream! I am stuck with a 090 on the rear but who cares since I am not spinning the tire up every exit. Keep us updated on what you do, especially the lightening part...
What class do you race in? I assume you are using Bridgestone tyres? What suspension/ engine spec do you have? If you are allowed engine mods you may be interested in what I plan to do to the head(when I get time to actually buy a bike) I will refresh the top end(new rings, lap the valves, clean pistons and ports And possibly skim the head, if there is room )add the lunch box filter and open race exhaust. then Dyno. After that I will be flowing the head and taking pictures and writing down what I do at every step. Then redynoing and posting the results here along with all the pic's and info(I'll have to contact a moderator to help with this). I would like to find out a way of making some cheap higher lift, longer duration cams, but haven't had any ideas yet.
I run in three classes: Vintage Heavyweight, Vintage Lightweight and Superbike Light. I won the championship in Superbike Lt over a highly modified fzr400 (I think the guy actually has a 600 engine in there ) and finished second in vintage lightweight by 9 points over a fzr600. Vintage heavy weight I finished third to the same fzr600 (took second place) and a really modified ex500 (I raced this bike during one race when I crashed my gs and this bike was drafting sv650's, just to let you know how modified that ex was!) My bike is essentially stock. I have a slight port job done (I would consider it a stage I) with gr650 cams in it. The gr650 cams are hotter than stock but not as hyper as full on race cams. I have a vance & hines race pipe and that is it. I am torn between building a motor with 79mm pistons in it or selling the bike and buying an sv. I am also exploring other engine options in a quest to get reasonable hp for the price. I love my gs but it is for sale so I can buy the sv to race next year. If it doesn't sell than I will dump about a grand into the motor and have at it again. The front end is stock with race tech internals and I have a gsxr600 rear shock internals fitted to the stock rear shock. I missed out on buying a works shock a few weeks ago, which bums me out. I should have jumped on it and didn't. Next year for the front end I will be installing a front end from my 93 gsxr750 since I have one laying around and will just have to pay to get the stem modded to fit my gs. Keep us posted as what you do, I am especially interested in seeing a hp figure. I want to build a race motor but do not want to have to rebuild it on a regular basis because it was made into a grenade.
Quote from: fastedmiami on November 01, 2009, 06:38:37 PM
I run in three classes: Vintage Heavyweight, Vintage Lightweight and Superbike Light. I won the championship in Superbike Lt over a highly modified fzr400 (I think the guy actually has a 600 engine in there ) and finished second in vintage lightweight by 9 points over a fzr600. Vintage heavy weight I finished third to the same fzr600 (took second place) and a really modified ex500 (I raced this bike during one race when I crashed my gs and this bike was drafting sv650's, just to let you know how modified that ex was!) My bike is essentially stock. I have a slight port job done (I would consider it a stage I) with gr650 cams in it. The gr650 cams are hotter than stock but not as hyper as full on race cams. I have a vance & hines race pipe and that is it. I am torn between building a motor with 79mm pistons in it or selling the bike and buying an sv. I am also exploring other engine options in a quest to get reasonable hp for the price. I love my gs but it is for sale so I can buy the sv to race next year. If it doesn't sell than I will dump about a grand into the motor and have at it again. The front end is stock with race tech internals and I have a gsxr600 rear shock internals fitted to the stock rear shock. I missed out on buying a works shock a few weeks ago, which bums me out. I should have jumped on it and didn't. Next year for the front end I will be installing a front end from my 93 gsxr750 since I have one laying around and will just have to pay to get the stem modded to fit my gs. Keep us posted as what you do, I am especially interested in seeing a hp figure. I want to build a race motor but do not want to have to rebuild it on a regular basis because it was made into a grenade.
You may not have to have a stem made up for your gsxr front end. First off measure the gsxr stem and the gs outer cone( Outer part of the bearing that fits in to the frame) Then go to your local bearing stockist and see if there is a bearing to match your 2 sizes. If there is you may be able to get away with making up a spacer or something similar. If they are just too different you could see if you can press out your gs stem from the bottom yolk and press it in to the gsxr bottom yolk. Do a bit of measuring first to see how much difference(if any) there is. I did this on my race guzzi front end, but have also had to have stem's made up for other bikes as the difference is just too great.
Your bike sounds like a bit of a missile if it is beating FZR600's. I have been thinking about the GS head alot and I think the limiting factor is that it is a 2 valve head and you can only get so much gas in there with out trying to squeeze bigger valves in to the head(which can lead to other problems, like valves touching on over lap,loss of power at lower and mid revs ). I was wondering if anyone has tried fitting a GSX400 head to a gs motor. You may have to machine the pistons a little, but you would get higher compresion ratio and probably a better squish from the smaller combustion chamber and the 4 valve heads give a greater valve area. I will have to keep my eyes open to see if I can pick one up cheap.
There is also a lot of stuff in the engine that could be looked at to remove weight, but until I get one I am only speculating.
One thing that I know works on these motors(I had a gs 400 in a galaxy far, far away) is to remove the starter motor and all the starter clutch etc. Then take the end off of the starter motor that fits in to the engine case and weld a large bore piece of alloy tubing to it, which you then fit a rubber tube to(I think the inside diameter was about 25-30mm) the tube then runs up the side of the bike in to a catch tank. This relieves almost all of the crank case pumping pressure and the motor spins up quicker and generally feels fitter. But the down side is that you then have to bump start all the time(the gs 400 has a kick start as well as the electric start).
Do you have any pic's of your bike? I'd like to see it.