Harder clutch springs

[Joseph]

Hello

The engine build i'm performing has got me thinking about the clutch setup

Lock up systems are readily available for these bikes, but i'm hoping to be able to avoid the expense and hassle and just go with uprated clutch springs

The problem with those is how heavy they make clutch operation on a bike, but since i'm building a car, the foot operated pedal should provide more than enough leverage to get it moving without too much strain.

So, question :

The GSX1400 shares the same gearbox as the Hayabusa.

Does that mean that the clutch and therefore clutch springs are compatible ?

The part numbers don't match between both bikes, but, i'm guessing that that would potentially be due to the Spring rating (like the old GSX 1100 F and the GSXR 1100 : same size springs but softer on the F due to less hp and torque)

The only uprated springs i can find for the GSX 1400 are made by EBC or Tourmax, both brands are 💩 from my experience, so, if Busa springs are the same physical size, i can buy some quality ones that would fit and provide extra pressure ?

[Eric GSX1400K3]

Mr Tony Nitrous should be able to tell you.

I did fit a new clutch pack which included stiffer springs, tbh I did not find them much harder. Can't remember the make, could have been EBC, but no issues at all

[Joseph]

Mr Tony Nitrous should be able to tell you.

I did fit a new clutch pack which included stiffer springs, tbh I did not find them much harder. Can't remember the make, could have been EBC, but no issues at all

Sounds good.

I've found Busa clutch springs rated specifically for turbo busa use in cars, it would seem ideal if they were the same size as the GSX ones 👌🏻

[BanditsHigh]

How much stronger do the springs need to be ... could you just add in a few spacers so that the springs are compressed more?

All the best ... Barry

[Joseph]

How much stronger do the springs need to be ... could you just add in a few spacers so that the springs are compressed more?

All the best ... Barry

Thats an excellent question, to which i have absolutely no answer 

I am not an engineer, i don't even have any kind of mechanical background or training, i just think and look around at what could/should be done.

In my case, we have a GSX 1400 that will be pulling a 400-420 kg car. Thats not heavy for a car, but, it's 50% more compared to the bike.

I've got a propshaft and two 9 inch rims with 235 tyres to get turning in order to get the power to the ground.

With a theoretical output of between 200-250 hp, that must mean that i need a substantially heavier clutch system clamping the pack together ?

If having a foot operated pedal means no hard effort that would wear a hand out rapidly, surely having around double the rate wouldn't be too much ?

Again, if i had any engineering talent i'd get at it with calculations, but i think that the heavier springs available for this bike will be a bit light ?

[hard road]

my guess would be a good healthy clutch would handle it, but a set of heavy duty springs won't go amiss.   

[KiwiCol]

Joseph, maybe a start in the calculations could be working out the total friction area of the 1400's clutch and comparing it to the total friction area of a car clutch.

As for the extra pressure, maybe ask a drag bike builder what they do for those engines, that'd give you a pretty good idea of what to aim for.

[Irish in Oz]

I know a guy that races one of these with a busa motor, dont know much about it but he did get a clutch special for it as he kept on blowing them.

[Eric GSX1400K3]

How much stronger do the springs need to be ... could you just add in a few spacers so that the springs are compressed more?

All the best ... Barry

Thats an excellent question, to which i have absolutely no answer 

I am not an engineer, i don't even have any kind of mechanical background or training, i just think and look around at what could/should be done.

In my case, we have a GSX 1400 that will be pulling a 400-420 kg car. Thats not heavy for a car, but, it's 50% more compared to the bike.

I've got a propshaft and two 9 inch rims with 235 tyres to get turning in order to get the power to the ground.

With a theoretical output of between 200-250 hp, that must mean that i need a substantially heavier clutch system clamping the pack together ?

If having a foot operated pedal means no hard effort that would wear a hand out rapidly, surely having around double the rate wouldn't be too much ?

Again, if i had any engineering talent i'd get at it with calculations, but i think that the heavier springs available for this bike will be a bit light ?

not sure about that. I wonder what the turboed 1400s on here use? A lock up clutch would be good on the drag strip as you are only really shifting up, but imho not in a race car application if continuously shifting up and down.

Adding spacer washers only limits the travel of the slave cylinder and means you'd chew the clutch up and risk damaging gears as it would never fully disengage. You need stronger springs (as you said) that have a higher spring constant to keep the stack clamped on the steel plates as the power comes on from the engine.  I reckon Hayabusa clutch springs would work or other aftermarket heavier springs (same wire diameter  total height and od would be needed.  Easy enough to change out

[Hooli]

Joseph, maybe a start in the calculations could be working out the total friction area of the 1400's clutch and comparing it to the total friction area of a car clutch.

But then diameter of the clutch plates affects the 'leverage' it's got against the power. That's probably the wrong word but I know what I mean.

[Joseph]

Yeah i think it really is down to getting some correct springs isn't it ?

I had a lock up clutch on this Turbo GSXR i owned for a short while, they can be setup for normal road use and it was very good to have when really opening the throttle up with no consideration to staying safe or reasonable 



But that would be another 500-600€ to add to the build, if i can get away with solid springs it would be preferable for my current finances

Like you said

a higher spring constant keeps the stack clamped on the steel plates as the power comes on from the engine

[Joseph]

But then diameter of the clutch plates affects the 'leverage' it's got against the power. That's probably the wrong word but I know what I mean.

Also that but i can't increase clutch surface by much if at all ? Maybe i could get in another steel and fiber ? 

[Hooli]

I doubt they'd be room. But I'm sure some drag bikes with turbos are running a lot more power than you'll have so it'll probably even out.

[grog]

Joseph, check out Hayabusa Zone. Lots of options but they have heavy duty springs.Not expensive. https://www.hayabusazone.com/clutch.html

[Joseph]

Indeed, price is a good point if they fit

I'll take my clutch cover off and get to a spring, to see if they can confirm dimensions.

I can't see them being different in size, but thats me and my wishful thinking