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Discussion Starter #742
Dave {Dragonstaff} was just here to pick up his GL 1200 carbs and while here he helped me to get the thingy onto the scales at either end with equal thickness wood blocks at the other.

Got a total weight of 197 kg. with a full fuel tank.

Not bad.

Needs more weight reduction. :D That's around 28 kg. lighter than factory.
 

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The pictures do not do this bike justice. The level of detail is ridiculous and it would take days to find all the little things Mark has done. I know I didn't in the little while I had.

All in all, this is a really nice bike.
 
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Dave {Dragonstaff} was just here to pick up his GL 1200 carbs and while here he helped me to get the thingy onto the scales at either end with equal thickness wood blocks at the other.

Got a total weight of 197 kg. with a full fuel tank.

Not bad.

Needs more weight reduction. :D That's around 28 kg. lighter than factory.
Um by my novice reckoning you'd be at 'bout 48-50kg advantage already; 28kg or so for the bike and >20kg lighter rider compared to most forum members...
 

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Discussion Starter #749
Yep, weight loss of any component including rider is far easier and cheaper than more power.

I've looked at the calculations for this, but I think they are beyond my mathematical ability.
 

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Yep, weight loss of any component including rider is far easier and cheaper than more power.

I've looked at the calculations for this, but I think they are beyond my mathematical ability.
Many an older rider will probably remember drilling holes+++ in alloy for bikes such as the CB series-that was before the days of carbon fibre/ceramics etc etc.
When we compare the weight of the CX against modern machinery the CX weighs close (or more??) than most 1000cc modern bikes (HD excluded).
Maybe the real test for the "thingy"is a club track day applicable to "older bikes"- with suitable test pilot???
You've already achieved a lot in weight reduction(y)-so maybe the satisfaction of seeing it keep up with comparable bikes will put any doubts to sleep-I have avoided any suggestion of traffic light drags :p
In the absence of any track test/club test knowing that you and the "thingy" is 50 kg lighter than any other CX and rider could be enough-a lot already achieved-i'm envious from the bike perspective and also the rider perspective-I'm struggling to fit in those leathers I bought 20 years ago (lol)
 

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Yep, weight loss of any component including rider is far easier and cheaper than more power.

I've looked at the calculations for this, but I think they are beyond my mathematical ability.
Which mathematical problems?
I am not an engineer, but science and physics degrees-happy to have a pm if you want an opinion.
Love to see this project reach your expectations.
 

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Discussion Starter #753
My google research only left me more perplexed.

How many HP to LIFT X amount of weight and other expressions non relatable to the search.

I know there is a rule of thumb for this.

In fact, HP can be back calculated from weight and 1/4 mile ET.

I just can't find what I'm after.

I'm waiting for the new drag track outside of Adelaide to open and want to have a few runs.
 

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My google research only left me more perplexed.

How many HP to LIFT X amount of weight and other expressions non relatable to the search.

I know there is a rule of thumb for this.

In fact, HP can be back calculated from weight and 1/4 mile ET.

I just can't find what I'm after.

I'm waiting for the new drag track outside of Adelaide to open and want to have a few runs.
1/4 mile and or dyno will tell you a lot (y)(and reflect things like "tractive force".)

"tractive force" and similar calculations might not be that useful in the absence of major changes to swing arm/weight distribution or actual centre of gravity changes-dunno if this concept was one that you encountered in your reading
 

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Discussion Starter #755
There is a motorcycle dyno quite close to me. The minimum number of pulls is 3 at over $50 each.

I do happen to know a feller who is friends with the owner and is interested to see a figure.

The COG will be much lower - both the bike and my seating relative to the bike. Those bars actually don't seem that low once riding as the seat height is so low. The reach is fairly normal if you crowd the tank, which is how I've always ridden.
 

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I thought it was a simple ratio of power to weight, basically dividing the power available by the total weight (we used to say "ponies per pound") to determine which should be quicker.
wouldn't that be watts per kilos in your neck of the woods? :D
 

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Discussion Starter #757
Found an online calculator.

Standard CX at 496 lb {225 kg.} @ 43 RWHP = power to weight ratio .087 hp per pound.

I'm awarding the thingy 50 RWHP for this. Hopefully it's not too optimistic.

Thingy at 434 lb {197 kg} @ 50 RWHP = 0.115 hp/lb
 

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You have to use the total weight. The bike isn't going to accelerate when there isn't someone on the seat....

BTW: You don't need an online calculator for that. Just divide the weight by the horsepower.
50/434=0.115
 

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Discussion Starter #759
I realise in real terms that the rider weight should be added but if someone else comes up with a weight for their bike we can compare apples to apples.

I also found that sum Bob.But thanks anyway. :)

With rider 584 lb {265 kg} @ 50 = .086 hp/lb - almost exactly the same as the standard bike @ 43 without rider.

Stock bike + 58 kg = 624 l/b {283 kg} @ 43 = .069 HP/LB
 

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I did rough calculations for my bikes years ago, based on estimated weight and spec sheet HP and they gave the same number for both Eccles with the 650 and Mr.H with the 1000 (including my weight + riding gear). It seemed counter intuitive for the 650 to accelerate better than the 1000 but the ratios verified that it should.
Of course, now that Eccles is a 500 and Mr.H is a 1100 the opposite is true...
 
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