Britbike forum Forums British Motorcycle specific Brands Bsa bulletin board Horse Power to hit 150mph ?

I have a particularly silly project in the pipeline .... a 150mph straight-line blaster ( it will never be road legal) 800cc 2 stroke V8

i see that the speed record for a 50cc is 145mph ( dont ask me how) but with this in mind what do y'all recon would be needed to propel a pile of scrap metal to 150 /.... on a long clear beach?

1 speed direct drive and as dangerous as they come hahhah Brakes and steering are for sissys

interested in all comments

It depends on how well it's streamlined.

Are you planning to lie flat on the tank and seat in your Speedos and sand shoes like Rollie Free?

A stripped naked frame lowered bike would need 75 hp at the rear wheel...

nah back couldnt do that /// i was thinking more along the lines of a recliner so my not inconsiderable mass could assist in lowering the center of gravity .... motors being behind a perspecs sheet in feild of vision so i colud see any chains being spat off etc

angled so that the wind would help push it down

THIS REPLY WAS TO SHANE .. for some reason the quote didnt work

I think PRT did something like this on his turbo? A65... Hopefully he will chime in.

149.99 mph at Bonneville, 152.866 mph at Loring, ME. My dyno (not calibrated) says 64 rear wheel horsepower, but likely less than 60.


(Scooter Grub photo)

Open class, 130 mph at Loring, 127 mph at Bonneville with about 61 hp (both those speeds with the enlarged 600cc motor). I predict you will need 95 hp to achieve 150 mph without streamlining.

Tom

Tom, have talked to the tuner of the Moto Guzzi that holds the MPG1000 record at Bonneville...157 mph, non streamlined of course...He claims the engine has never seen more that 83-85 rwhp hp on a dyno. However he didn't mention the air density during dyno testing. Guzzi's have a lot of frontal area and that doesn't help....

We never attempted to run the black bike naked but with the Cronshaw/ IOM style fairing we bettered 150 numerous times with nitrous only and turbo/nitrous..
BSA A-65 650cc. Carbs/NOS about 90 RWHP. Turbo/NOS close to 120. That whole bike is 'resting' while we work on the MPG bike. Good luck with your thing.

i still have aspirations for 140mph, naked , production frame, 650cc, NA, gasoline.

maybe delusions would be a better word?

heres what some guys have got out of 50cc DANG why would you bother

http://www.elsberg-tuning.dk/recordbikes.html

[img]https://www.bennetts.co.uk/-/media/...14C8C4BBDCA4603E51C8CA07B20860FE4DF9DAD7[/img]

A bit off topic but this is what's considered a naked frame in modern hyper bikes....207 Hp, 450 pounds wet, time distortion acceleration, 170 or so mph top speed as geared....

150 MPH is only a target .... u have to dream big right?

Im not certain if u are still allowed (as a member of the oppressed public) to buy Nitrous here but it would sure help eh.

should sneeky road tests at 3am make it look that 150mph is not really doable i can always save face by saying

"Oh did i say MPH .. i meant KPH "

surely i can ring 160kph , the tun. out of an 800 2 stroke v8

AND BIG BREAKTROUGH on the project .... my mate who is a master woodworker can get some SPRUCE and will make the engine mount "plate" and various air foils etc for me

So yep it will be a Spruce Goose hahhhahhh

149.315 mph with a tiger cub engine
using a "mostly" factory stock 200cc tiger cub engined (12hp ? ).... Streamliner , Triumph dealer Bill Martin's
fastest pass at Bonneville in 1959 .
was .... a one pass speed of 149.315 mph


2 way run was 139.82


​

Getting 60 mph out of a Cub was good going.

What he said.

I have a naked "street bike" with a claimed 90hp at the crank so probably about 80 (at most) at the wheel. I have seen 145mph on the speedo so someone lighter and crouching flat on the tank would probably (with slightly higher gearing) see over 150.

With a single speed and direct drive I think your biggest problem will be getting the thing going from zero unless you are planning to tow it and let it go at about 100.

John

With a single speed and direct drive I think your biggest problem will be getting the thing going from zero unless you are planning to tow it and let it go at about 100.

John[/quote]

pretty much what i had planned to do to get it moving initially,,, but might use a really long stick and push it with a support vehicle , at about 30mph hit the clutch and hope hahhah

Kevin, with the right fuel and conditions I'm sure your bike has 140 in it!

I would imagine that (8) 100cc 2stroke cylinders should have no problem pushing you to 160KPH or 100MPH. Not sure what base your planning to develop from but even with 12.5HP per cylinder your at 100HP. Will be an interesting project and you should definitely start a build thread with your progress.

Apologies for being a pedant but if you have a clutch then it is not direct drive. More of a single speed transmission.

John

Well its going to be a bit of both ....the "clutch" will actually be a huge V belt which will be tightened (engaged ) with a toggle lever ... i will be going for the contraption look

For you pushrod guys. At this years manx GP a norton ES2 had a podium finish and set a lap record of 105mph around the isle of Mann circuit. Some chaps from NZ built and tuned it!!

TEN H.P will do it, if you ride the bike off a 1,000 ft. cliff.

Like many repop bikes, that was a 500 single with a semblance to an ES2.
It looked vaguely like one same as the new Manx nortons and goldies etc.
I won't take/detract from the engineering but they are not even close to
the bikes they are emulating.
I've said before, if you file the head and barrels on a GSX 1200 and say it's an MV
or Gilera 4 (well it's a twin cam 4 isn't it......) you are on the same lines.

With that notion I could make a bicycle do just the same. 🤣🤣

Found a calculator online:
http://www.wallaceracing.com/Calculate%20HP%20For%20Speed.php

Coefficient of drag seems important.

Bill Martin's record bike must have had a very good coefficient, plus some cam work etc.