JBS 700 Kit on welded 80mm Crank

i suppose with the jbs kit is no longer available Its not really possible to derail a train with no tracks

as far as TQ vs power Im not edjumicated enough to explain the actual practical difference John

My bumblificated observations are that my 700 is way way faster at everything than my 628 which makes similar peak HP, has a lightened crank, Ti pin, 3015 cam bigger valves and revs its little head right off

the main advantage of the bigger engine is in low and mid rpm response which reduces the delay in initial acceleration, meaning everytime your speed is at a minimum from obstacles or pesky corners you gain a bike length or so over the other machines on initial throttle application, something the paddle tyre takes to another level again.

its not arm wrenching acceleration just a reduction in the small but important period of time it takes to apply power and regain momentum from the slowest speeds.

so i suppose this is measured as off idle tourque being higher .. more like an electric motor

this has been mentioned before i believe.

http://husaberg.org/supermoto/17580-650-tuning.html

Dr_C said:

"Genius" is far from it, but I can agree to "Persistent". But thanks for the kind words, Canolman!

In RR, manoeuvrability and smoothness beats power at most tracks. Generally, you need top end power at the tall straight, but a strong mid range to get out of EVERY corner.


Even better is a really smooth and sensitive delivery at 0-15% throttle to be able to crack the throttle directly after letting go of the brakes.

But, of course, more power is always fun, costly and giving headaches! You have received good ideas from Bushie, so I have nothing to add there. My strongest recommendation is that after you have installed all hardware, spend a day at the dyno finding out optimum pre ignition, jetting, intake length, exhaust length (and restriction) and finally jetting again. All in that particular order! Use the dyno to get value for all the money you spent on expensive "go fast thingies"! Otherwise it's all like buying beer and firecrackers.. Bushie can explain.

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bushmechanic said:

this is the best advice Ive read on power delivery for a long time and it applies to every form of racing except probably hillclcimbing and drags

increasing the minimum speed in each corner is the easiest place to make big gains but if you are not marky marques it is easier to go safe old man speed slow in the corner and have a good initial acceleration from the first bit of throttle, it is also easier to maintain the minimum speed, this is the main advantage my bike has over the smaller engined ones it jumps a bike length or so ahead when its time to go.... makes up for me being a slow old man it is also the reason i hate auto clutches since the initial take up is dulled

the firecrackers and beer are best when made at home in the shed from old shotgun cartridges and the hops of a kangaroo all on the same bench alongside a husaberg:ninja:

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I just wanted the discussion to start, always something to learn What I do know is that it's not about peak HP, it's all about the curve. A 2 stroke 125cc can have relatively high peak HP but the power delivery is another story.
And as power is torque x rpm the result is that the more torque you have at a certain rpm the more hp you will have at that rpm too. That 2 stroke 125 compensates lack of torque with high rpm's to achieve that peak hp it lives on.
So even if the torque is a static measurement it's the rpm that makes it useful.

berglsmerg said:

Ahh nuts to hp anyway, tq makes it go.

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"tq makes hp which makes it go."

Here is also some useful information on the topic: Power and Torque: Understanding the Relationship Between the Two, by EPI Inc.

The maths are not difficult. Whats interesting though, is that the capability of an engine to uphold a speed at a certain load (definition of power), doesn't say so much about it's performance in actual racing. Being able to uphold a speed with an increasing load is interesting for static engines in generators/hybrids and such. What does count is how the engine picks up revs during load! Then mechanical inertia, valve timing, inlet design, ignition advance, gearing ratio and so on, makes all the difference to the whole performance. Yes, a smooth and sensitive delivery is very important! But hey, at the end of the day, who crosses the finish line first is what REALLY matters! :happy:

So tq and hp make work, the more work you get out of it the faster you can be.

Wot have you done Bushie?

me? just watching mostly

its my brothers hillclimber. really is an awesome machine, hes done respectable laps around the MX track with it including 40ft jumps

i was thinking about the tourque vs HP stuff ... lets have both ... just take 1300cc with a 13500 rev limit and make some dust

Can we get a 1300 single to rev that high

140mm piston on a 80mm crank made out of negative mass depleted unobtainium?

be fun to watch

600cc with a desmo head could do it .. maybe not the most practical use of money

still firecrackers are gone in an instant .. "oooohhh ahhhh oohhhh"

250cc singles

https://www.youtube.com/watch?v=vcyT18qk8ls

Looks like the valve springs are dodgy....