revtothelimit - motorbike forum

I've been accepted on the club Friendface page, reading the posts it suggests that there might be 5 or 6 GPZ500's on the grid next season, I reckon it might be fun.

KungFooBob wrote: Thu Dec 04, 2025 10:39 pm

Le_Fromage_Grande wrote: Thu Dec 04, 2025 10:33 pm What about CX650, Guzzi V65 or BMW R65 ?

There's all manner of horrible Yamaha 4 stroke twins you could use.

Honda NT600V meets the rules, shaft drive FTW!

But no victory wheelies

KungFooBob wrote: Thu Dec 04, 2025 10:40 pm I've been accepted on the club Friendface page, reading the posts it suggests that there might be 5 or 6 GPZ500's on the grid next season, I reckon it might be fun.

Are there that many still running?

Le_Fromage_Grande wrote: Thu Dec 04, 2025 10:42 pm

KungFooBob wrote: Thu Dec 04, 2025 10:40 pm I've been accepted on the club Friendface page, reading the posts it suggests that there might be 5 or 6 GPZ500's on the grid next season, I reckon it might be fun.

Are there that many still running?

there's a few on T'bay and even more on Friendface Marketplace.

It would be even more hilarious if it were a KLE500.

Tricky wrote: Thu Dec 04, 2025 6:22 pm don't think I've ever seen anyone race a GPZ500, but the motors go reasonably well for what they are so reckon that should be a goer

Mate of mine in the US raced one for quite a few years in some kind of ministocks class. Quite successfully too.

They do go pop quite regularly, though, and handling is best described as 'interesting' (speaking from personal experience on both scores)

[quote=KungFooBob post_id=389449 time=1764888294 user_id=48

It would be even more hilarious if it were a KLE500.
[/quote]

It would be slightly funnier than that on an en500

ogri wrote: Fri Dec 05, 2025 4:35 pm https://southernbikespares.co.uk/ER5.htm

ER5's have a milder cam than the GPZ, but higher compression due to the cylinder head. So a GPZ cam in an ER5 head make optimal power... not that I've been researching.

Ditchfinder wrote: Fri Dec 05, 2025 4:33 pm It would be slightly funnier than that on an en500

Bagger racing training school.

Ditchfinder wrote: Fri Dec 05, 2025 4:33 pm [quote=KungFooBob post_id=389449 time=1764888294 user_id=48

It would be even more hilarious if it were a KLE500.

It would be slightly funnier than that on an en500

[/quote]

I used to know someone who had one of those and genuinely thought it was a fast bike with great handling

Le_Fromage_Grande wrote: Sat Dec 06, 2025 8:59 am I used to know someone who had one of those and genuinely thought it was a fast bike with great handling

Depends who's riding it,dunnit?

My Serow(XT225) is eligible. Faster than that thing ^^ anyway. If I take the baffle out.

Maybe.

GPZs are frigging quick, they just take off above 7k like a two stroke. Dunno about handling tweaks but younger me managed to wipe out the ends of the pegs on my one running BT45 Battlaxs.

Forget about the GS5, it's a plodder and the balance shaft will let go if you tev it too much.

If that class ran over here, I would by my old 119k courier bike back and give it a viking funeral on track

KungFooBob wrote: Wed Dec 03, 2025 9:52 pm I just think it'll be hilarious griding up on a GPZ500.

Especially if you stuff a KX500 engine in it....

ZRX61 wrote: Sat Dec 06, 2025 3:01 pm

KungFooBob wrote: Wed Dec 03, 2025 9:52 pm I just think it'll be hilarious griding up on a GPZ500.

Especially if you stuff a KX500 engine in it....

They might notice the spanny.

Skub wrote: Sat Dec 06, 2025 11:00 am

Le_Fromage_Grande wrote: Sat Dec 06, 2025 8:59 am I used to know someone who had one of those and genuinely thought it was a fast bike with great handling

Depends who's riding it,dunnit?

He was slower than the bike, the side stand got more lean angle than he did.

KungFooBob wrote: Sat Dec 06, 2025 3:06 pm They might notice the spanny.

In related news....

https://www.facebook.com/marketplace/it ... l%7D%22%7D

I had a gpz500 new in 87
Yeah def do it, the gpz was very popular racing in America maybe there’s some old reports on line. Be a great little bike to race I reckon

Bigjawa wrote: Sat Dec 06, 2025 2:46 pm GPZs are frigging quick, they just take off above 7k like a two stroke. Dunno about handling tweaks but younger me managed to wipe out the ends of the pegs on my one running BT45 Battlaxs.

Forget about the GS5, it's a plodder and the balance shaft will let go if you tev it too much.

Having owned both, the GPz was quicker, but the GS500E - the early 89 and 90 ones - with the claimed 54 horses weren't THAT far behind, and handled much better once the Biro springs at the front end were replaced with Progressives, and the rear shock modded with the same size one off the GSX600F, with a harder spring and better damping. My first one got despatched all over the UK, got ridden to the S of France on several occasions, did a few trackdays, and topped 138,000 miles before it dropped a valve.

Post 90, they got a bung in the exhaust to keep to new noise limits I believe, then there were carb mods, plus various little alloy bits like the fork brace turned to rusty steel. And the latter restyled GS500F was a horrid machine. I'd doubt they made much more than 30 hp as they wouldn't crack the ton (officer) and they also were significantly heavier which I suspect was down to low quality steel in items like the tank and frame, and low quality alloy in the wheels.

The ER5 was seriously detuned too, as well as incredibly fragile when dropped, as our trainees proved over and over. We soon put ruddy great wrap around crash bars on them so they rolled rather than crashed!