+0.7mph

Raised my best speed today by 0.7mph to 195.5mph on my 810cc 1984 GPz750 turbo. Only cost me a 1000 mile round trip to find out that the wastegate had cracked off the headers so I only had 1.9-2.0 bar boost when on the dyno it made 2.2 bar, but hey, that's racing! Unfortunately I couldn't just reweld it as it has cracked in the same place before so needs a redesign to prevent the same thing happening again.

I'll be back soon for another attempt at 200mph but in the meantime I'd like to say thanks for the messages of support I've had through this site

Hopefully I'll have some video of one of this weekend's runs later in the week.

4.6 mph to go to get to 200.1 mph!!
.2 bar (10%) ought to do it you think?

Still cheering you on !!

200 mph GPz750 Turbo, who'd a thunk it

i say 195.5 is plenty fast ontwo wheels!thats scooting! goodluck.

"Flat out like a lizard drinkin'..."



Loads more pics here

Why is your rear tire squashed so much in this picture and others??
Is it really loaded that heavily??

when drag racing (cars at least) you want to run as little tire pressure as possible before you start to get a wobble on the top end. less tire pressure makes it sit flatter, giving the tire a larger footprint and that makes it less likely to spin off of the line. i assume its the same for bikes, keep dropping pressure each pass till it gets squirrly at the top end, then add a little so its stable, and has the max footprint for hard launches with no spin. my uncles drag vette only runs 7 psi in the rear tires.

I had the local shop put a new tyre on. They thought I would check the pressure before running. I thought they would put the right pressure in when they fitted the tyre so didn't check it for once. End result - it only had 16psi in all weekend :blush:

how much do you normally run for the strip?

77KZ650 wrote:

how much do you normally run for the strip?

I think the pics are of his land speed racing attempt, not a 1/4 mile race.

Lorcan, you know you deserve a "Dope Slap" for this one, right?? :evil:

Yep, Grade A muppetry :laugh:

I usually run about 12psi for quarter miles and 40-45psi for the top speed stuff. Probably cost myself a couple of mph there. Luckily there is always another event, there is a records meeting up north on Monday/Tuesday but I don't know if I will make it yet. If I do, you can bet that the tyres will be pumped up!

Lorcan,

Keep us all informed about where you are running your bike. If you are ever within travel distance from Northern Cal, I would enjoy seeing you make a run. I would even volunteer to be a pit crew assistant, so you would remember to check the air in your tires!

Come to think of it, I think my tires are only rated for 130 mph. What kind of tires does a 200 mph bike run, anyhow?

GO LORCAN!!!!!

You can use any modern sportsbike tyre really, usually ZR (over 149mph) or W (over 168mph) rated. The daft thing about the higher speed ratings is they don't say how much over 168mph is ok! But for what we are doing i.e. short bursts there aren't usually any problems up to 220-230mph, although some care is needed with suspension settings to prevent "chunking" on the big hp bikes. For longer runs like at Bonneville the experts recommend "shaving" the tyres to prevent the tread overheating and delaminating.