Dynojet stage three gpz500s

[Simple]

stop laughing I'm being serious,

anyone else done this? what air filters and exhaust did you have

I have the option of a stage 3 kit for the GPZ,

thoughts?
possible problems?

I have the options exhaust wise of stock system, a motad nexxus system and duplicates of each which can be customised.

Simple
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Insta - FemFeral

[Ichy]

Stage three is generally with modified air filter, usually pods, and an aftermarket, free flowing, exhaust. Neither of the systems you mention really qualify although I guess you could try taking the baffles out. The Stage 3 will usually give a bit more top end but at the sacrifice of torque in the 2-4k area.

The jets are likely to be too big, although some kits come as stage one and three. If the kit is a real good price then you can buy the correct sized jets for a stage one kit from a K&N dealer for about £1.50 each.

The stage three and above that I've fitted have generally been a real pain to get set up correctly.

[instigator]

[veeeffarr]

Laser probably make a system for the GPZ

[stinkwheel]

By definition, a stage 3 kit requires pod filters.

Having messed about with those engines a fair bit, I would be loath to bin the airbox. The GPZ airbox is what gives it that banzai acceleration at high revs, there must be some serious pressure-wave action going on in there. My mate who knows about such things tells me it is not unusual for a well designed airbox to be scavenging 110% or more of the engine capacity. That means it'll suck in 10% more air with the airbox fitted than it would with open bellmouths.

I also know for a fact that Kawasaki spent a massive amount of their R+D budget on carburettion research during that era, that's how they made the GPZ900R (from which your bike is derived) into the first sportsbike to crack 150mph. I also know that they employed accoustic engineers to design the airbox for the ZZR1100 which was THE fastest bike you could buy for a considerable period.

Small things can make a big difference, ask anyone who decided it would be a good idea to cut the small plastic baffles off the inside of the airbox on their NC30 in an attempt to 'derestrict' it.

So, I would suggest going no further than stage 2 which would involve a K&N filter and sporty pipe.

In all honesty though, they are fast enough for the chassis they are in as standard.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Simple]

air filters we have sorted, exausts current best plan is to remove the rivets from the stock system and remove the baffles.

I dont think the motad system has much in the way of baffles left

I wont be fitting the kit just yet, leaving it stock for winter plodding about to uni and back, however for tracktime next year I'd like more oomph from the same 'shitter'. So contemplating the kit now as it's cheap.

Simple
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Insta - FemFeral

[Ichy]

[bish777]

I had no trouble getting my GPz750R running on pods, but i have had alot of experience with messing with carburetion.

You can get over the pressure wave effect of the airbox by adjusting the needle position and drilling the slide vacuum holes, but it does require alot of work and patience.
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GSXR1100J

[Simple]

Hmm, mayb it's not worth all the agro and lost riding time for 10% more power?


those who've managed to pull it off, would you do it again for the same amount of time for the same end product?
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Insta - FemFeral

[bish777]

Id leave the thing alone, if its running well and pulling how you like, leave it.
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GSXR1100J

[Simple]

it runs well, just liked the idea of a bit more oomph, and its a subtle change ad the filters would be almost hidden by the fairings
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Insta - FemFeral

[bish777]

fitting a more open pipe, then upjetting a little is the most likely route.

That or getting a bigger bike?
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GSXR1100J

[Kickstart]

Hi

I would say the stage 3 kit is to get a bike which has been screwed around with in other ways to run decently again, rather than something you fit and then screw around with the bike to get it to work.

Airboxes and inlets are designed just as carefully as decent exhausts. Dumping the airbox and hacking out the baffles is not likely to give you anything much at all.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Simple]

hoki, Value your opinions, I'll leave as is, I've looked at bigger bikes and they require a bigger budget and there's nothing quite like lapping ATGNI's on a GP-Shed

thanks you boys and girls
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Insta - FemFeral

[stinkwheel]

As I keep telling people. If you want to go faster on a GPZ500, spend your money on the brakes and suspension, not on the engine.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[bish777]

You could shoehorn a Z1300 motor in there?
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GSXR1100J

[Simple]

I'm happy with the brakes, they're very good, I'm outbraking many on track, just the extra oomph I'd like.
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Insta - FemFeral

[Irezumi aka Reuben]

The weight balance of the whole chassis is too biased towards the rear and there is too much flex sideways at the front of the bike.

If I was going to mod the bike I'd get a bar mounted between the two spars towards the front of the frame and perhaps fit some stronger (triple?) yokes. Try raising the rear and dropping the front as well.

Or just buy a better bike.

As Stinkwheel said do the suspension if your on the cheap. New shock and stiffer springs, or at least make sure you have 15W oil in the forks.
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Pictorgraphicalfantastical

[tsmith]

standard gpz500 will put out 52 rear wheel hp, you can get +2 hp by fitting slip on rear race cans from here: https://www.classicbikes.com/sarachu.html
carbon fibre model will shave 4kg off the bike

and another +2 hp by fitting K&N air filter, drilling a 1" hole in the airbox and setting the carb pilot screws to 2.5 turns out. instructions here:
https://www.stevemorley.com/ex500/airbox/
and here:
https://www.ex-500.com/index.php/topic,2311.msg678.html#msg678
and here:
https://www.ex-500.com/index.php/topic,124.25.html


don't fit pod filters and don't change the jets. way too much hassle and the bike doesn't run right.

[Simple]

mine makes 46.4 bhp at the rear wheel.

thanks for the advice guys I'm not into spending that kinda money will just look for a 600 to race instead.
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Insta - FemFeral