Engine question (for the engineers!)

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.... ;-)

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Originally Posted by 470four

[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!

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

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.

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!

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Originally Posted by 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.

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Just passin' on the pain! ;)

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

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Originally Posted by jonnydangerous

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

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

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

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

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Originally Posted by Jon_W

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

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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

Ah, the good british compromise... ;D







Lovely bikes though!!!! 8-)

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

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

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.

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Originally Posted by 470four

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

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;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!!!

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Originally Posted by 470four

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

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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

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Originally Posted by jonnydangerous

[quote author=470four link=1300369264/51#51 date=1301494799]
One big piston making BIG fat thumps of power almost from tickover??!

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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[/quote]

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...