Engine question (for the engineers!)

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 ;)

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. :)

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

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

Quote:

---

Originally Posted by 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

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

---

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

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

Yup long live the VFR

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-)

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

Quote:

---

Originally Posted by 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-)

---

(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