126,875mph. Stock Production 1983 500XC

the 400/430 are great and pull a long ways thanks to the powerband and gearbox. they do not however "match" a swede 500. thats a different beast.

no, I was referring to the new kato 500 4 bangers

2012 Kalahari Desert Speedweek was run on a dry lakebed.
I entered the bike with WR gearing which is 33/76 primary and 17/48 sprockets.
Knobbly reached 164kph and proved unstable.
Roadsport had less diameter and ran 166kph.
Negate "tyre slippage" on a 53hp machine. This only occurs with big hp.
Engine was screaming at well beyond what is healthy for it.
2016 was run on slightly inclined aircraft runway.
XC primary is 39/70, no other dirtbike in existence offers this tall gearing potential.
Sprockets 14/48.
Top speed was easily reached in less than 700m and i just shrieked onwards to the kilometre trap.
Rpm was recorded at 7900, which is 1500 beyond max power and well into the dropoff of powercurve. I have not dynoed this engine but it certainly makes more than the previous.

2017 will see me concentrating on 1km runs with taller sprocketing to cross traps at 6500rpm.
400m drags would be a completely different setup alltogether.
My point is 500cc stock production (yes a great deal of time into blueprinting), aircooled.
I have developed a 500 lc but due to pipe and reedvalve setup it cant run as stock. In development phase this engine has a lot more power and potential than aircooled Husky.

164kph is about 102 mph.
This thread was started on Oct 15 , proof of your original 126,875 mph claim ?

@ dukkman
http://www.speedweeksa.com/

#11

Yes Gary M, i sourced 2 sets of seals from a bearing supplier and tested to 15psi. They are of a higher rating than the viton type.

Impressive numbers! Professionally timed too.

Ta Johan

Congratulations Brother - very well done !!

The cr500 husky uses the 39/70 primary.

We drag raced a lot of bikes. The ported 81 cr250 beat newer kawies kx 125/250's they couldn't touch the 250. My '86 400 cross country beat a 250 KDX bad. We clocked the kx's top end at 85mph. Against a streetbike. The 400 walked all over it.

I never thought of the option of playing with the primary gear ratio and the tranny cr & wr ratios for the optimum ratio for top end speed.

At that rpm your up over 4500 fpm for mean piston speed . I thought 4000 general regarded as the upper limit ? I'm not trying to argue just curious as I'll never be in your situation

Tnx Trev. I trust your XC still rips.

Bill Ive done all of that on th 4 and 6spd trannys, and can advise. Never had a 5Spd to play with and for 1/4 miles it would be my 1st choice.

Streak, im well aware of piston velocity. With a 400 odd gramme slug at such rpm the smallend bearings dont like the stress and i replace regularly. Eventually the bigends also go beyond tolerance.
My pistons are prepared for additional lubrication. Premix is 20:1 to 25:1 and i use a full synthetic oil for microlights. The viscosity is way thicker than other top brand oils. Normal 93 or 95 pumpgas. 50:1 mixes and fuel additives are bs.
Piston to cylinder clearance and squish are also increased.

Ultimately i want to cross the traps lugging at 6500 rpm.

Good stuff . Thanks for the response .

so 100 :1 is not recommended?

Yea it's 100 to 1 . 100 kph per 1 wheel lol

What is the oil you use if you don't mind sharing . Purely for Mt own curiosity

Go by the maxima chart with oil ratio. Drag racing at a higher steady rpm requires 20-:1. The mix thins out at a steady rpm. Don't ask me how I know.

There's a example to go by. The pro mods/ drag race cars are using the two speed power glides over the 400th auto tranny. There's so much horse power you want to get thru the gears to get it to the last gear to pour it on quickly. Now to me when I drag raced my shifting was at maximum rpm/power was 6,700 rpm on the big block Chevy. Shift at 6,700rpm and go thru the traps at 6,700 rpm. That's as fast as she's going to go once dialed in. I forgot to turn on the e fuel pump and shifted at 3,500rpm she would rev up. I ran 12.85et 1/4 mile. That's another story stupid me. A good day but a bad day too.

I'm thinking drag racing a motorcycle would be the same theory. I just purchased a tach from eBay $10. Just for ha, ha's.
I'd like to drag race a built dirtbike. Motard rims and tire balanced. I know my Italian husky 250wr ran in the 12 second 1/4 mile or better. She flew stock.

When I raced husky chainsaws at the local fairs speed cutting some guys were using aviation fuel with 100:1 optimal. I ran high test pump gas with husky oil. Plugged governors, larger driving sprocket. Rakers at
.060" on the chain. For pine I went .080". One mean 100cc saw. At 50:1 mix.

I was playing with a Honda 600cbr on the street with my stock gearing on my husky 98/250wr. I pulled him of the light, wheelies and was ahead when he let off as I was beating him. He didn't want to lose but he would of beat me as we went faster but I didn't tell him that.

Talking and comparing the 390, 430, 500 we have different strokes and from a higher rpm (smaller bore) to the lower rpm but more torque with the bigger bores. It's like comparing a Chevy 283, 327 to a 350. Throw a roller cam in a 283 she's going above 10k rpm. She's all rpm. Now how fast can we get the rear wheel turning. Ratios.? A cr tranny will keep the rpms up. But a or tranny might be better?

I was using motorex full synth at 100:1 in my wr 400 for some time with no dramas. I should qualify, I DONT recommend these ratios in a/c bikes. I use the castor 727 at 40:1 now as the kato shop folded.