Engine question (for the engineers!)

[Squashed_Fly]

Why does a V engine produce more torque than an inline engine?

Is it because (on a litre bike example) as there are only 2 cylinders (I'm presuming on a twin?), they are much bigger bores so in theory 500cc each cylinder, thus producing more power, whereas the inline 4 engine of the same size only has 250ccs per cylinder?

Or have I got the completely wrong?

Can anybody explain it in laymans terms?

[Nooj]

A twin doesn't necessarily produce more torque, it just produces it sooner.

There are lots of variable involved (firing order, size and shape of exhausts and velocity stacks, valve sizes and timing etc.), but generally, bigger pistons with longer strokes (more common on twins than fours) produce more torque earlier on in their rev range.

[Snowy]

Power and Torque are two different things in much the same way as Voltage and Current. Not easy to explain in laymans language, try a quick google and see how you get on. :)

[jonnydangerous]

nooj has hit the nail on the head....
because of the mass of the rotating and oscillating parts on a twin being heavier, they generally have a lower rev limit, therefore you can have the same "mean piston speed" (the actual speed im metres a minute that the piston moves at, cos if it goes too fast it wears too fast) with a longer "Lever" (the crank offset from main bearing centre to big end centre x 2) to create a larger "turning moment" (Torque).
a v twin will generally have a longer stroke

if you can imagine, a short stroke 4 cylinder 1000 does 13,000 revs, where as a long stroke twin 1000 does 10,000 revs. the long stroke has further to go than the short stroke, so the mean piston speed is higher at the same revs, but ultimately the mean piston speed is the same at both redlines!!!!!....
therefore less levering effect on the 4 cylinder 1000, and more on the twin 1000 at the same revs...so more torque to the twin at one set revs.
and as nooj said, they make approx the same flat out, but at different revs.

with me so far?.....

4 stroke normally asperated engines have now reached peak volumetric efficiencies (about 97% for a good one) that means that a 1 litre bike draws approx 970cc of air in one "cycle (2 revs) as it only loses a bit to turbulence and heat absorbtion.

the only way that manufacturers can now get more power is by higher rev limits (shorter strokes as the mean piston speed cannot go any higher) or by supercharging (positive displacement or exhaust driven) as these allow a higher Volumetric efficiency than 100%.......

it wont be long before we see a return to turbo bikes OR the return to bikes with mid range power, and less top end (as soon as the public realise that top end is useless on the roads apart from about 3% of the time)......

now, ask me a hard one???...... ;-)

[Jon_W]

Ok, back to basics.

Power = energy relesaed in each fire X number of fires per second. (or to quote Keith Duckworth, "the size of the bangs times the number of bangs per minuite")

Torque = The force developed by each fire X the length of the crank. Imagine a lever, the more weights you pile on it the more that has to be put on the other end to balance it. The same if the weights are further from the fulcrum.

Force = pressure X area of piston

There are limits to engine design to consider as well. The piston speed up and down is limited by design due to friction. also the amount of time that the charge has to flow into the piston limits the top end performance.

Ok, here's where it gets fun. A two cylinder engine produces a few bigger bangs for a given rpm. The bigger bangs are however not as punchy (hence lower pressure) due to the larger volume. To keep the volume down and get a bit more work, the stoke in increased. This gives greater torque but at the cost of rpm due to piston speed limitations and charge inlet times.

The four cylinder engine has a smaller combustion volume and can get much better pressures, but the pistons are smaller, hence less force. The soultion is to reduce the stroke and enlarge the piston diameter, this gives a greater rpm but can cost torque and top end.

The torque differences can be settled by the gearbox...

As you can see there is a lot of difficult compromises to make. And that's just in simple terms. The complexitied of cam profile, combustion chamber shape, inlet and exhaust lenghts, pressure waves etc all have a part to play as well.

Hope that answers the question.

[Snowy]

Well, you did ask..... ;D ;D ;D

[Jon_W]

Lightweight diesel.

The future. :P

[Squashed_Fly]

So if ultimately, they make about the same power at the top of the rev range, yet V-twins have more usable power/torque lower down the rev range, and what Jaydee says is true about only getting near the top of the rev range 3% of the time on the road, then why don't more people have V-Twin engines where they can use more of the power more of the time?

There must be a good argument somewhere for having to thrash the nuts off something to get it to work as well as something that doesn't need the nuts thrashing off it...?

Or have I missed something in the process? I am trying my best to follow, understand and keep up!

[Mark_Able]

Four cylinders is smoother. V-twins, no matter how well designed, still vibrate a fair bit. Some people don't mind (Harley riders), others prefer the refinement of a four. :)

[Dabz]

or get the best of both worlds and go ask Triumph for one of their lovely triples :D

[b_m1957]

The pull you get after 6,000 revs on a 600 inline 4 just doesn't happen on a 600 v-twin, at any rev range.

Or at least that it's how it feels having owned an SV650 and a Thundercat. Could never go back to a v-twin now. Would love to try a triple though next ;D

[Nooj]

Really, you need an engine in each configuration, to go with what mood you're in when you open the garage door :-)

I like instantly thumping past traffic and launching out of corners like a catapult on the Falco, but I do occasionally like to scream the tits off Debz' Fazer.

Given the choice the twin always wins for my riding, I really do think they make the best road bikes. An in line four is too smooth, too much like a car engine for me, I want something that feels 'alive' in a bike.

Again with a triple, it feels too smooth and sanitised for me. Bikes for me should feel raw and threatening, not like they're powered by an electric whisk.

The Cross Plane Crank R1 is fun for a four cylinder though, it feels more like a twin, but still has the mental top end rush of a big IL4. Good luck at using all the performance on the road though, unless you go every where in 3rd gear. If you're used to four cylinder litre bikes you really need to have a go on one, they have a very different character and are an incredible bit of kit.

[wiltshire builders]

I find twins a tad lazy. On an inline 4 you really have to work the gearbox to keep the revs up. The difference between the two is decreasing though as manufacturers get more top end out of twins and more torque lower in the rev range from 4s.

[jonnydangerous]

missing the point slightly here SF......
the inline four may make less torque at a given engine speed, BUT will have the gearing to result in the same torque at the rear wheel for the same road speeds as a twin....BUT the 4 cyl will ultimately rev higher and produce better top eng power (and possibly a better top speed and performance in the top of the rev range).

for the same rear wheel torque the two bikes will be doing approx the same road speed but the 4 will be revving higher, but both bikes will have the same mean piston speed.....

its the resultant torque at the rear wheel you want to assess, not the torque at the crank :-)

[Squashed_Fly]

Ok, now you're starting to lose me! lol

Thought I was doing ok keeping up thus far! ;D

[Jon_W]

So if ultimately, they make about the same power at the top of the rev range, yet V-twins have more usable power/torque lower down the rev range, and what Jaydee says is true about only getting near the top of the rev range 3% of the time on the road, then why don't more people have V-Twin engines where they can use more of the power more of the time?

There must be a good argument somewhere for having to thrash the nuts off something to get it to work as well as something that doesn't need the nuts thrashing off it...?

Or have I missed something in the process? I am trying my best to follow, understand and keep up!

Errrr...... No!

They make different power and torque curves.

As JD says, the torque can be sorted out by the gearing. What drives you along is torque, not power. The power is the rate of work or energy dissapation so the rate of changes. The top acceleration rate is (all things being equal) determined by the power as is the top speed.

So to demonstrate:

Using Kinetic energy Energy (kE) = 1/2 Mass (M) * velocity (v) squared we can see that as the speed (scalar velocity) (v) doubles, the energy requred to maintain the momentum increases by a factor of four.

From this we can differentiate to say: The rate of gain of kE:

Power (dE/dt) is proportional to, 2 * Acceleration (dv/dt) = Force (N) / Mass(M)

The Force element can be then used to relate to Torque through Torque = Force * Radius, so linking power and torque together on the road.

So power is used to gain momentum. The more power (and torque by inferance) or the lower the Mass the faster you will accelerate, but not neccisaritly go faster because of resistance

Taking wind resistance, the major factor. Assumin the bike is going at a constant speed:

Force of wind (Fd) = Drag factor (c) * velocity (v) squared

and applying it to the equation for potential energy:

Potential energy (pE) = the change in work (delta U)

pE = delta u = integlal (Fd).dx =a + 1/3*c*v cubed.

So you can see as the speed rises the losses due to wind resistance rise dramatically.

So the Power absorbed by the wind is proportional to c*v squared.

The rolling resistance can be assumed to be fairly constatnt throughout.

So, as can be seen. Power is lost though many sources. The engines headline figures are only opart of the story. As JD says. All had to be based at the power and torques applied to the road, not the engine figures as transmission losses can be hideous.

[Hunar]

:-?

[Jon_W]

A nice bit of Newtonian Mechanics and calculus for you in the morning!!!! ;)

Does ya good!!!! ;D

[Hunar]

I need a spliff after that!

For one horrible second I was transported back in time to a physics lesson!

[Squashed_Fly]

Blimey, if that's laymans terms, I'd hate to see you explain something to someone who understands it all!!!!

I was ok at "bigger bangs but less of them" but now totally lost! lol

Gunterpot did spend some time with me explaining the relationship between power and torque, drawing graphs to show why I had a much higher revving powerband (the point where power crosses torque?). Which I kind of understood when I saw it on paper... But now totally lost again! ;D ;D ;D

[Jon_W]

It is a far from simple explanation. The relationship in the engine is the core of any engine development as it affect many other things.

Thnere are two definitions you need to get sorted:

Energy: The size of the bang

Power: The size of the bang time the number of bangs per minuite

Torque: The amount of twist turning the wheel.

[Jon_W]

I need a spliff after that!

For one horrible second I was transported back in time to a physics lesson!


;D ;D ;D

I used to do my degree work in the pub.... numbed the pain!!!

[Snowy]

The bit that's really going to get interesting is when you ask what's the difference in power v torque between a V twin and a Parallel twin and a Horizontally Opposed twin and does it make a difference where the cylinders stick out in relation to the crankshaft, gearbox and clutch i.e is the V twin a Ducati or a Moto Guzzi configuration............

Or don't think about it since each engine configuration has it's plusses and minus, pro's and con's etc etc, not everyones cuppa tea etc etc etc.

[Scotty]

A 90º V-configuration does have perfect primary balance in memory serves me correctly (hence Hardly-Worthits vibrating like road drills with their 45º angle, and Aprilia Mille twins needing a balance shaft for their 60º twin). A conventional in-line 4 has perfect secondary balance, the "Rossi-inspired" cross-plane crank R1s require a balance shaft, something that explains why that engine is about 5kg heavier than the previous generation one... ::)

Here's a suggestion - buy a book and read it!

[Jon_W]

If i remember correctly, the best balanced engine possible is a 90deg v12.

The issue with balance is that the piston does not follow simple harmonic motion, rather a very spiky and uneven version of. So static balance can be achieved fairly easily, but dynamic balance is harder.

There are books out ther, but they do assume a certian amount of knowledge.

[wiltshire builders]

There are books out ther, but they do assume a certian amount of knowledge.

Yeah i'll leave it then. ;D

[Jon_W]

Ok. To finally answer the question.

Be prepared, this could get messy.....

Right, to basics. The reciprocating (piston) engine is classed as a non-flow heat engine, and so is subject to the rules of the Non Flow Energy Equation (NFEE).

This states that Q+W=deltaE which can be shortened to Q+W=U(2)-U(1)
Where
Q=Heat transfer
W=Work (energy)
U = Internal energy

So far so good.... now to add in the "fun"

The idealised petrol engine follows the four stroke Otto cycle. The Pressure - Volume (P-V) diagran illustrates the cycle.

http://upload.wikimedia.org/wikipedia/en/1/17/Diagrama_pv_de_ciclo_4tempos.png

A = isobaric (constant pressure) expansion (inlet stroke)
B = adiobatic (constant Q) compression (compression stroke)
C = isochloric compression (constant volume - spark) and adiobatic expansion (power stroke)
D = isochloric expansion (exhaust) and isobaric compression (exhaust stroke)

For the purposes of working out the work done by the engine the isobaric processes can be discounted. But for working out the total output the losses due to friction on these strokes bust be re-inserted.

Lets look at the curved lines of Adiabatic expansion:

So PV^gamma = K where gamma is the aidiabatic index, typically 5/3 for air.

Adiabatic processes assume no heat transfer to or from the working fluid. Hence Q = 0 So going back to the NFEE we can say that:

W = U(2) - U(1) or dW = dU but dW is a partial differential based on Q so this is where it gets complex! I'll not go into the detail but...

We can deine U = anRT
a = (alpha) = 1/2 the number of degrees of freedom
n = amount of fluid in moles
R = universal gas constant (don't ask!!)
T = Temperature

to find the change in U dU = anRdT

We are assuming here that the gasses are ideal and behave. This is a ver close approximation to reality, so we can apply the Ideal gas equation of:
nRT = PV
so dU = a d(PV)

so W = integal(between V(1) and V(2) of P.dV

Inserting the aidiabatic PV^gamma gives us W = integal(between V(1) and V(2) of P(1) (V(1)/V).dV

This becomes a hugely complex equation whic I cannot right in text!!! But the above shows us that the work done in an adiabatic process is described by the area under the curve.

No, we have two adiabatic processes, B and C on the graph. C is an expansion on the power stroke, and B is a compression done on the compression stroke. So the power gioven by each explosion is given as:

W = W(C) - W(B)

or the area between the curves.

So on to the isochloric processes.

With these we can say that as there is no change in V, the piston is not moving, so W = 0

Back to the NFEE, Q = U(2)-U(1) or dQ = dU (dQ is again a partial differential linked to W).

I won't go any further again, but you can see that at this moment all the heat (Q) is added by the ignition (look at the vertical line C) and removed in the exhaust (the vertical line D)

So, these lines represent what goes in and what comes out the exhaust. This is the first stage in determining the efficiency of the cycle.

So, we now have an idea of the work done each cycle, we can determine the Power as described in the previous post.

So to Torque.

Torque is a moment of force described by M=Fd

M = Moment (Torque)
F = Force
d = distance

Now, force can be calculated as Pressure X Area, and we have equations describing pressure. So all we need to do is to work out the mean pressure in the cylinder during expansion and minus it from the mean pressure during compression.

For this PV^gamma=K can be used.

We know V from the piston positon and Gamma so P=K/V^gamma. From that we can work out the average Pressure.

We can now differentiate this to get a figure for the average rate pressure change.

Simples.

What this shows is the physical link between torque and power within the conbustion process. It is far from simple (the above is a gross simplification, in reality ignition and exhaust are not at constant volume, and the exhaust and inlet strokes are no constant pressure, but the sums for that are more than I can write here.... let alone explain in a "simple" format....

Hope this finally answers the question. :)

[Snowy]

I think the moderators should lock this thread. Inflicting such pain on the membership should stop... I'm sure there must be swearing going on in here as well ;D ;)

[Squashed_Fly]

n = amount of fluid in moles



How much fluid is in a mole?

Wonder if this little guy can help?

http://upload.wikimedia.org/wikipedia/commons/thumb/3/3e/ScalopusAquaticus.jpg/800px-ScalopusAquaticus.jpg

[StreetHippo]

If you squeeze them hard enough you'll find out!! ;D ;D ;D

Stu

[Gixxer_Tom]

I've ridden few twin's and a a few in-line fours, the power delivery feels sooooo different...

The reason i Ride an inline 4 and not a V-twin is because the Twin's can be abit too punchy, ALL or nothing kinda power...

Try coming into a corner quickly on a V-twin and tryin to excelerate out of it when the roads damp...soooo much harder on a v-twin in my opinion then on an inline 4!

Not only that....but ALL bikes are different! its not just power, but brakes, geometery, weight, suspension that all give a totally different ride!

Believe it or not i'm much quicker on my Gsx-r 600 then i am on an R1!

The Gsx-R suits my riding style.. i didnt just buy a bike and hope for the best! ;)

Its all about finding a bike that works with you...or has the fondation of a bike that you can mould into the perfect bike for you..

My advise would be to go book a few test rides, Try a Gsx-R 600/100, and R6/R1...and a few V-twins....

You'll start to build up a picture of what the pro's and con's are for v-twins and inline4's and understand soooo much better then reading any of the above! lol.

Triumph 675R 2011 available soon!!! That 'Mark My Words' will be a monster of a bike!! :)

Ps - Jaydee you know too much dude! lol

Thomas ;)

[470four]

Im going to have my shot at this in laymans terms without frying peoples head's... ;)

Imagine a bicycle. Your legs are the pistons, the crank is the crank (Simples) You are limited by the power strokes you can put in by your fitness, weight and gravity, putting in two downward strokes pushing down twice every revolution.

If you had another person sat at 90Â* deg to you, they would put power strokes into the crank from another direction, helping the crank to spin instead of having the power come in from one direction only.

An inline 4 cylinder engine would have two people sat side-by-side with a joined crank - this would be difficult to get going initially, but once it was spinning it would be real easy to spin as the riders got the gear going!

A BMW horizontally opposed engine (big trailie adventure bike stylee) would have one crank, two pedals, with one leg on top and one underneath, pushing strongly from either side alternately THUMPTHUMPTHUMP giving ooodles of low-down power - this engine configuration not being overly popular due to you having two cylinder heads stuck out either side to crunch into the floor & kerbs if you drop the bike :o

Twins have two large pistons rather than 4 small pistons giving more thump per stroke - a 1000cc twin would have two 500cc pistons rather than the inline four's 250cc pistons hence a bigger bang!

Twins tend to run into breathing problems at high revs - its a BIG pot to fill at high speed, plus the larger piston has a lot of weight inertia to sling quickly backwards & forwards (a CBR400's crankshaft at its redline of 14,500 RPM (crank Revolutions Per Minute) is spinning 241 TIMES A SECOND!)

Hence we come to the ideal arrangement - a V4 engine as per MotoGP bikes, basically two V-twin engines side by side, the small pistons giving a good top-end capability and the power strokes coming into the crank from two different angles giving good low - rev power/torque/grunt/whatever...

Yep. :)

[Beamer]

hmmm.... I may have to print that off and read it very slowly.....excellent description tho (i think)....i almost got the first bit hehe

Well done tho (honestly)...Im sure the techie heads got that perfectly.... I only learn by seeing and doing....(I learnt that on a training day hehe)...so its gone straight over my head...got any pictures?? lmao ;D ;D ;D ;D ;D

[Cemorah]

Err I thought a 4 Stroke engine fired every 2 revolutions of the crank.

So the BMW boxer version would be 2 one legged cyclists hanging off each side of the bike pushing every 2nd turn of the crank that I gotta see! ;D

[470four]

Err I thought a 4 Stroke engine fired every 2 revolutions of the crank.

So the BMW boxer version would be 2 one legged cyclists hanging off each side of the bike pushing every 2nd turn of the crank that I gotta see! ;D

Lol granted! Unless it was a 2-stroke... :-*

[Snowy]

The Boxer engine design has both pistons at TDC at the same time however when one is on "compression", the other is on "exhaust". As far as ignition is concerned they both fire at the same time, known as "wasted spark".

So, both pistons fire at the same time but only one goes "boom". ;D

For those interested:

http://www.animatedpiston.com/BMW.htm

[Cemorah]

Nah cos then they would be allowed to push every turn - but still only with one leg ;)

Yup long live the VFR

[Squashed_Fly]

The bike description works for me. Trouble is, I can't work out where the mole sits? ;D

Based on your prognosis, I am off to buy a motogp bike... 8-)

[Jon_W]

Ok, moles does not refer to the small furry thing thar destroys your lawn...

Is refers to the molecular weight of a compound when comaperd to carbon 12 (don't ask.... there is more than one type of carbon). It is the standard way of determining the amound of gas, as getting gas on scales is difficult :D, if you know the volume of a gas, you know the number of molecules, and from the molar mass, you know the mass in moles!!!

SIMPLES!!!! ;D ;D ;D

[470four]

The bike description works for me. Trouble is, I can't work out where the mole sits? ;D

Based on your prognosis, I am off to buy a motogp bike... 8-)

(Get me one while you're there!)
The only inherent failing with the V4 is that by design, they are a comparatively heavy engine & difficult to work on any sense... Two seperate cylinder blocks with all the necessary radiator hoses, extra coolant, carbs wedged in the middle & 3.2 miles of exhaust piping that looks like a bag of snakes make life difficult when Things Go Wrong... Sparkplug changes usually involve you wishing you had extra elbows/longer fingers & having to unbolt the radiator to get to the front two plugs!

Needless to say the power benefits outweigh the disadvantages & seeing as MotoGP bikes are now made of carbon fibre, magnesuim, dandelion fluff & fairy hair (bad lot of fairy hair in that blokes back wheel the other week...) they still seem to get by. :D

[jonnydangerous]

agree with 470four! anyone whos ever STOOD on the carbs on a VFR400 to get them into the intake stubbs will NEVER buy another v4...hahaha....

...il NEVER have another one.... ;-)

[Jon_W]

[Get me one while you're there!)
The only inherent failing with the V4 is that by design, they are a comparatively heavy engine & difficult to work on any sense... Two seperate cylinder blocks with all the necessary radiator hoses, extra coolant, carbs wedged in the middle & 3.2 miles of exhaust piping that looks like a bag of snakes make life difficult when Things Go Wrong... Sparkplug changes usually involve you wishing you had extra elbows/longer fingers & having to unbolt the radiator to get to the front two plugs!




;D ;D Since when did the designer ever care about the poor smuck who had to service it.... just cram it in there......

[Harry87]

470four actually used a great example to explain this question. I really don't understand why JonW threw all that degree level physics in SF's face when he acted for a simple explanation.

[Squashed_Fly]

I quite like reading the scientific stuff, even if I don't understand it all. Anything that allows me to post poor mole jokes is good in my book!

[Jon_W]

470four actually used a great example to explain this question. I really don't understand why JonW threw all that degree level physics in SF's face when he acted for a simple explanation.


Just passin' on the pain! ;)

[jonnydangerous]

and dont forget the most important thing...."twin cylinders suck donkey pole" and fours are the best.... ;-)

[Jon_W]

and dont forget the most important thing...."twin cylinders suck donkey pole" and fours are the best.... ;-)

No WAY!!! Two cylinders are far superior.... four is just too many.

[Scotty]

If that's the case, how come there are no twins on the MotoGP grid then? :-?

Fours are better than ditch pumps, any day... ;D ;D ;D

[Jon_W]

Didn't say they were faster, just better. Look right, sound right, feel right.

[Snowy]

Didn't say they were faster, just better. Look right, sound right, feel right.

I like both, but then I would say that wouldn't I since I have both ;D ;D

but really really really would like a triple as well :D

[Jon_W]

Ah, the good british compromise... ;D







Lovely bikes though!!!! 8-)

[470four]

Triples...

One long crank with three pedals, lefthand, righthand & centre - a near PERFECT comprimise between the revvy four-cylinder engines with little bottom end grunt but good powerful top-end & the twins with good bottom-end but no top-end rev-out.

(Would this bicycle configuration need a three-legged man to ride it? How would he sit on the saddle? Not sure... Am on 12-hour nightshift's this week so just be glad this stays coherent & I dont go wibbling on about treefrogs.)

Think of a four cylinder bike engine as a petrol car engine & a twin as a diesel car engine and you wont go far wrong!
Triples are nicely balanced due to their layout - less moving parts too! Tend to be narrower than a Four (only three cylinders so can be bunched up more) so give a smaller & lighter bike. :)

Singles... Simplicity being the key here - nice and easy to work on, just one of everything so easy to troubleshoot. The bigger singles can be a pig to start, especially anything British or a hot engine, four-stroke singles will only fire every other crank rotation so trying to get a good swing on the kickstart when it is at its best place in this cycle takes a lot of practice (swearing, broken ankles, broken boots, broken kickstarts, swearing)

Thankfully modern technology has given us electric starters for the bigger singles and they can make excellent road bikes if you arnt in too much of a hurry? One big piston making BIG fat thumps of power almost from tickover??!

THUMP THUMP THUMP THUMP THUMP THUMPTHUMPTHUMPTHUMPTHUMPTHUMPTHUMPTHUMPTHUMPTHUMP THUMPTHUMPTHUMPTHUMPTHUMP :D

[Harry87]

I heard a giant cruiser (HD?) outside GW last time I was there start up in that exact pattern of thumps.

[alanTDM]

One long crank with three pedals, lefthand, righthand & centre - a near PERFECT comprimise between the revvy four-cylinder engines with little bottom end grunt but good powerful top-end & the twins with good bottom-end but no top-end rev-out.

My Yamaha TDM850 is a twin and that will rev out,The red line is at 8K but it does have a 270 crank rather than a 360.

[Jon_W]

Singles... Simplicity being the key here - nice and easy to work on, just one of everything so easy to troubleshoot. The bigger singles can be a pig to start, especially anything British or a hot engine, four-stroke singles will only fire every other crank rotation so trying to get a good swing on the kickstart when it is at its best place in this cycle takes a lot of practice (swearing, broken ankles, broken boots, broken kickstarts, swearing)

Thankfully modern technology has given us electric starters for the bigger singles and they can make excellent road bikes if you arnt in too much of a hurry? One big piston making BIG fat thumps of power almost from tickover??!

THUMP THUMP THUMP THUMP THUMP THUMPTHUMPTHUMPTHUMPTHUMPTHUMPTHUMPTHUMPTHUMPTHUMP THUMPTHUMPTHUMPTHUMPTHUMP :D

;D ;D

If you want fun to start, try a Velocette.... with the low ratio kick start, they can be an utter pig!! But for all the convinience of electric start, there is somthing satifying about kicking a bike into life!!!

Anyhow, my old dream would rev out at 10.5k... 360 crank with balancers. As smooth as!!!

[jonnydangerous]

One big piston making BIG fat thumps of power almost from tickover??!



hahaha, please come and tell that to my WR250f ;-)
thats a single cylinder 250 with FECK ALL torque and 11,000 redline with all the power in the top 2000 revs ;-)

;D

[470four]

One big piston making BIG fat thumps of power almost from tickover??!



hahaha, please come and tell that to my WR250f ;-)
thats a single cylinder 250 with FECK ALL torque and 11,000 redline with all the power in the top 2000 revs ;-)

;D

I suggest you get it serviced/rebored then :D

Joking! The little singles will never be stump-pullers, hence bigger bikes are avaliable... ;)

Honda's CBR250RR redlines at 19,000RPM - and as such remains a much wanted bike for my Fantasy Garage Of Joy. :) :) :)

Imagain the abuse factor... they sound like F1 cars...