Hi guys. Anyone had any experience with single cylinder engines?

Got any advice/tips about using them versus your standard 600 cc high revv-vvving 4 cyl beasts?

Which is best, KTM 520, Yamaha WR450F,
Ducati Monster, Honda CRF450F or Husqvarna 500? are there any others?

dan

There is also the Cannondale 440.

Ricky

I wonder if anyone here knows about jawa or jap motors. They are very powerfull and very light. Incredible amount of development has been done on these over many years. They run on methanol but I would assume they could be converted. They are 500 cc engine to boot. I just dont know if e-85 would cool them enough.

I know each of the 450s can probably be taken out to 470. Unfortunately without a restrictor, they can maybe hit 60 hp. Too bad you can't use 2 strokes. I smell a yamaha banshee engine hittin 100 hp woot.

lots of teams run single cylinder engines...we run a 2004 KTM 525exc engine. very torque rich little items

we looked at those jawa engines, quite cheap, quite agricultural, possibly a good way for a team on a budget looking at getting into the single scene. As far as i remember some run on petrol....
we looked into large displacement singles (ktm's 525 and a few 600's) but considered them too lumpy. we're happy with our choice of yam wr450.
I heard a rumour however of formula student 2006 being held at rockingham speedway, using half the track and an infield section (a bit like the indy gp) if this were the case, I'd imagine there'd be more high speed stuff playing (slightly) into the hands of the bigger BHP 4 cylinder engines....

The YZF 450 out of Yamaha's race quad is quite a torquy little engine, i'm not sure how the restrictor will affect it, and it probly won't be an easy one to get a hold of

yamaha's yfz450 quad engine is only 426cc, the wr is 450cc's. to all other intents and purposes they are the same engine. be careful you don't recommend the yz450f engine to teams though, the enduro bike version with NO ELECTRIC STARTER. i believe it is the same as the wr but with slightly advanced timing.

The yfz is closer to 450cc @ 439CC, not 426cc.

What you can't kickstart the car? just kidding

I can see it now, integrated sliding pedal tray and remote kick-starter...

It actually wouldn't be that complex a linkage....

I was just reading about batteryless EFI for snowmobiles, totally eliminate the battery, throw a kick starter on a CBR 600 and we will be golden.

you guys that use honda CRF450 and yamaha WR450, how do you get round kick start?
did you get brand new engines?
think you could get electric start on WR450F as of 2004 and honda's latest CRX450 is electric start.

people have been saying to me that the single cyls are quite unreliable, particularly compared to the likes of CBR 600 which apparently run forever. is that true?

anyone know anything about Husqvarna engines?

has anyone got power/torque/weight data for the single cyls?



dan

yam wr450 has been electric start for a few years now...
the wr is on the edge of design, there are holes cut in everything to reduce the weight i'd say they are on a factor of safety of about 1.0000001, and we're anticipating making not far off stock power. the CBR is 120bhp or so stock, and there's not many teams pushing out more than 100bhp, therefore the engine isn't as stressed.
i heard our engine guy mumbling about reshimming after 10 hours running or so which also sounds abnormal and an inconvenience...
were still working out our optimal runner length by physically adjusting a telescopic runner on the dyno so we've not got power or torque curves yet, we anticipate our (initial) final map in a month or so, it'll be posted on our homepage & i'll copy it here when we've got it. Off the top of my head though i'd say 30kg, 50bhp and 50Nm but that is very speculative. We do have a supercharger for it arriving in april too........ but i really don't want to use it because
a) it's an additional complication on a wonderfully basic setup
b) i doubt the engine can deal with it even with the reinforced conrods and additional gubbins we're having made up
c) it's another headache in the general scheme of things
d) look at delft, rmit and tokyo's sprint lap times from formula student 2004 (plus remarkably Delft's acceleration time of 2nd)
1 - RMIT - 30.58
4 - Delft - 31.81
5 - Tokyo - 31.82
they all ran with a "basic" NA setup and the 450 singles got 3 of the 5 fastest times, therefore in a basic NA setup, this engine in a formula student car (certainly over the Bruntingthorpe track) appears to be able to cut it

Danzim, The WR450 is a handbuilt factory race engine, not a production road bike engine, so it won't do 50000km btwn rebuilds.
Has nice stuff in it,like roller bearing crank/conrod assy. (you don't have to log oil pressure-it doesn't really have any!) It is usual to rebuild at 5000km's if raced. If the oil/filter is changed every racemeeting and only full synthetic race oil used the engine is bulletproof, can't kill it with a big stick.
Only one proviso, don't attempt internal mods! The motorcross guys who modified 450's mostly ended up with box of bits. They got YZ's if they wanted to go faster. The YZ has diff exhaust cam, stronger bottom end and approx 1000rpm higher limit.(12k) But the electric start setup cannot be retro fitted. I would advise that the WR only be rebuilt by a factory trained tech. who knows these engines, shop around.
If you get inlet/exhaust/mapping spot-on a stock engine will make 67+ hp @ 10.8k and a flat torque curve from 5.5k to 10.8k.

cheers halfast.
jonno, 30 kg sounds about right. is that what you got when you weighed it? did that include the carbreuttor?
if anyone's interested, the honda CRF450 is 32 kgs inc carb and a bit of oil, we weighed one the other day.

what do people think of the now discontinued, air cooled honda XR600 (42 kgs, 51.9 Nm torque at 5500 rpm). if only it wasn't kick start.

Danzim, that 30kg is approx i can't remember exactly what it was, i'll bang it on the scales in the morning for you to get a precise figure
I don't really like the idea of air cooled engines... whilst they are basic and increase the simplicity of things, I can't see without impressive ducting (or with the single head tilted out to one side) how you can get a good airflow behind the drivers seat. Teams do run them, so they do get them working though. any teams run an aircooled?

we're going for the Yamaha WR450F for NR3 as of today! how exciting! we need to get a CAD model. does anyone know where/whom i should ask. our CAD engine is autodesk inventor. don't know whether that's unusual or not. perhaps different formats can be converted? any ideas?

i've got a solidworks .sldasm, an ideas .mf1 and an .igs file. send an email to me00jhg@brunel.ac.uk and I'll forward the relevant one to you (i'd have thought an iges would be most likely to go into autodesk)