ok ok i know the gs (stock) has 40 horses. i mean the ones that have done mods to increase horsepower . i dont remeber but i read a post that a cople of you managed to get 60. post yours.

on the old board Ryan ( so cal guy havent seen him here in ages ) shaved his heads 1/15000th of an inch and did something else and go about 63 hp or so..

The last i heard of him he was busy with school

If he is getting 63 HP at the wheel, he did a hell of a lot more than shaving the head that little bit.  I would think it would involve shaving the head, porting and using larger pistons, or at least a head/cams/valves from a larger displacement bike.  Also carb/intake/exhaust changes. A 50%+ jump in power is not something one does over the weekend for kicks.   :mrgreen:

I have 60 hp+, but it takes quite a bit: bored to 80 mm with aluminum sleeves and Nikasil; 12:1 high compression 80 mm pistons; high lift Webcam cams, with shim under bucket lifters; ported head; 36 mm Mikuni carbs; full Hindle exhaust; removed flywheel and alternator; and race fuel.

Planing the head (I did 0.018"), pod filters, full after-market exhaust will maybe get you to 45 hp.

Bob B. has probably over 60 hp with stock bore, GSXR 4 valve per cylinder head; FCR carbs; balance shaft, alternator and flywheel removed. He maybe has higher compression too?

It aint the horses, it's the torque.

Quote from: Cal PriceIt aint the horses, it's the torque.

Huh?! Torque is just HP divided by rpm. No magic. HP is what makes it go fast. If you are racing, torque matters very little. Good hp over a usable spread of rpm is all that matters

Quote from: Cal PriceIt aint the horses, it's the torque.

In cars yes because you have more weight to pull/push around. On a bike you dont have the weight problem so it doesnt come into play as much. Torque on a bike just makes it feel fast but it isnt really..ie harley's and cruisers.

how much horsepower does a cobra f1r slip-on put out. iknow not much but i wanna see if it does anything else other than make it sound better.

Quote from: 96gshow much horsepower does a cobra f1r slip-on put out. iknow not much but i wanna see if it does anything else other than make it sound better.

Sorry.  Slip-ons use the stock header pipes, therefore they flow the same as stock.  Also have little to no effect on power output.

so what are slip ons for? Other than making noise??

2 purposes.  More desireable looks and a more desireable sound.

Quote from: glenn9171

Quote from: 96gshow much horsepower does a cobra f1r slip-on put out. iknow not much but i wanna see if it does anything else other than make it sound better.

Sorry.  Slip-ons use the stock header pipes, therefore they flow the same as stock.  Also have little to no effect on power output.

If that was true then re-jetting would not be required - and it is.  

When the bike is flat stock the biggest restriction is the air filter.  If you put on a slip-on or a full system then you would probably not change the jetting required a whole bunch - There are people who have put on full systems and the bike jsut gets a little cranky - the choke point is on the intake side.

K&N pods open that up considerably.  After that the most restrictive element is the muffler - a better flowing muffler will allow a further increase in flow.  My bike - which had been re-jetted to work with the K&N filters got very lean when I added a Cobra F1R.  The jump in jet size required was not nearly as great as going to the K&N type pods - but it is there.

After that there may be a further increase in flow due to larger head pipes on some full systems - but I think the size of the ports is the greatest restriction at that point.

Quote from: glenn9171

Quote from: 96gshow much horsepower does a cobra f1r slip-on put out. iknow not much but i wanna see if it does anything else other than make it sound better.

Sorry.  Slip-ons use the stock header pipes, therefore they flow the same as stock.  Also have little to no effect on power output.

If that was true then re-jetting would not be required - and it is.  

When the bike is flat stock the biggest restriction is the air filter.  If you put on a slip-on or a full system then you would probably not change the jetting required a whole bunch - There are people who have put on full systems and the bike jsut gets a little cranky - the choke point is on the intake side.

K&N pods open that up considerably.  After that the most restrictive element is the muffler - a better flowing muffler will allow a further increase in flow.  My bike - which had been re-jetted to work with the K&N filters got very lean when I added a Cobra F1R.  The jump in jet size required was not nearly as great as going to the K&N type pods - but it is there.

After that there may be a further increase in flow due to larger head pipes on some full systems - but I think the size of the ports is the greatest restriction at that point.

Whether a slip on helps or not is irrelevenet caus they are crap.  Buy a full system if you give a damn about performance.

Quote from: gs50000eWhether a slip on helps or not is irrelevenet caus they are crap.  Buy a full system if you give a damn about performance.

Thats a moot point without valid fact backing it up. What about slip-ons makes them inferior??

Have you hear of putting a cat back on a car? SAME THING. Stock mufflers are always restrictive (except for maybe a west coast chopper or something)....

Replacing the muffler helps.. otherwise, as stated above, no jetting would be needed.

Why is it then that it has always been said that rejetting is not necessary with slip-on's but it is with full systems?  The GS is lean from the factory, so it needs jetting with the stock setup.  In Anne's dyno graph, she had it jetted and had a full system with an aftermarket filter.  Still only made about 2-3 HP more than stock.  A slipon alone wouldn't make much of a difference, then.

Quote from a popular retailer's website in their FAQ section. "Exhausts with enlarged mufflers, while usually still louder than stock are not as loud as drag pipes and do have some back pressure and do not require jetting. "

Quote from: glenn9171Why is it then that it has always been said that rejetting is not necessary with slip-on's but it is with full systems?  The GS is lean from the factory, so it needs jetting with the stock setup.  In Anne's dyno graph, she had it jetted and had a full system with an aftermarket filter.  Still only made about 2-3 HP more than stock.  A slipon alone wouldn't make much of a difference, then.

Quote from a popular retailer's website in their FAQ section. "Exhausts with enlarged mufflers, while usually still louder than stock are not as loud as drag pipes and do have some back pressure and do not require jetting. "

If all you did was add a slip-on to an otherwise stock bike re-jetting is not required because the restriction in the system flow is on the INTAKE side - the stock airbox/air filter.  That is also why the K&N that fits in the airbox comes with a restrictor to install if you do not want to re-jet.  Just getting rid of the stock air filter opens things up - keep the stock filter and make all the changes you want in the exhaust - it really will not make much difference.  

Now, if you want to say that a full system is better than a slip-on - I may or may not disagree with you depending on which full system and what you think means better.  Generally larger head tubes raise power up high and reduce low rpm power - wether that is better or not depends on how and where you ride.

I am learning a lot from this thread

i know leveller did this and a couple others. but when you do dual exahst with a slip-on on each side, does that increase power. i know it sounds better because he sent me some vid clips of him riding it up and down the street.

i think slip-ons are most useful not for outright power gains, but smoothing out the power curves....if a bike has a very noticable dip in power at a certain rpm to the point its annoying, people might want to look into gettiing a slip-on....i think at least a little power can be expected if unrestrictive intake and rejetting is used....THIS IS NOT FACT IT IS MY OPINION DONT KILL ME PLEASE