FZR250's

[Kye]

Might have the chance of getting one soon from a mates parent, are they any good? I'm after something I can restrict down for when I get my lisence, was thinking about a 125 but I'd get bored and realistically they are well below 33bhp standard anyway, and a 250 2stroke won't restrict down very well.

Are these any good for relatively new rider wanting a sports bike? (already have a scooter for the college run)

Any common problems I should check for?


Cheers, Kye

[Frost]

They are 45bhp so they should be easily restricted should you want to do that. The only problem with them is that they are damn rare, so any problems with it and you could struggle for parts.

Usability and design wise they are great little bikes which will do all you want without scaring the holy crap out of you!

[Robby]

The FZR400 is rather fragile, and this revs 6000 rpm higher...

I wouldn't get one, its probably a case of get a good one and it'll go on for ages, get a bad one and it'll break constantly.

[mchaggis]

Is that the case with all high revving 250 four strokes? If the CBR250 really can rev to 22000 rpm, then surely it's going to break if you so much as look at it the wrong way?

I was semi-tempted by the CBR250 for a while, until I realised it'd probably be far too small. Hence I'm just going to pootle around on CBT for a year then do DAS and get a GPX/Z 5 or 600.
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[RS1Banger]

I bet that'll sound amazing, 20 grand on a nice loud exhaust, it'll be like listening to a grand prix.

[stevo as b4]

if its in good condition id get it mate, just change the oil,filter, about every 1500miles, and use good stuff and im sure it would be fine. On such a high revving motor it might well be worth having the valve clearances checked regulary, say every 5000miles. I like the style of older FZR's with the projector type headlamps, and the agressive attitude. The FZR600 for example, was always far more of a hooligans bike than the CBR600.

[dandit]

[Kye]

Thats what I though nice ultra high revving 4 stroke (can't beat a 2 stroke but at 19 grand red line you cant complain)

I'm the sort of person to service ultra regular anyway, oil change every 1000 miles, I'll check clearences every 3k with it being so high revving (and the way I'll ride it)

With it being restricted for a bit It should last a while anyway

I'll take my old man with me to check the bike out, then probably get it anyway, I need a bike really, very powerful scooters are fun, but there's a definate limit with them, and its mainly an acceleration / around town scooter, need something for the open roads

[dandit]

[mchaggis]

[dandit]

[Kickstart]

Hi

To a large extent the revs make not much difference as the engine was designed to rec like that.

The FZR valve clearances are almost certain shimmed and with small light valves they should rarely need touching.

All the best

Keith
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[mchaggis]

I just had a vague recollection of something my technical tutor was saying about two years ago... Apparently, Ducati's haven't got valve springs, rather the valves are opened by one cam and closed by another. This cuts out the loss of power in compressing the springs, supposedly if you get a Ducati desmodromic (the name for this springless system) valve train you can just spin the cams with your hand and watch all the valves doing their thing.

Does this mean the Ducati's can rev higher? I'd have liked to have thought so.
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I must not be a troll...
Mmmm, Guinness
Discovering the delights of Hammerite and a 3/4" brush.

[cagiva gezzer]

It means they don't get the valves bouncing, or whatever they do?!

High revving 250's are not a problem, as each cylinder is only 62cc, so the stroke and inertia forces are very low.
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"because one stroke isnt enough and four strokes waste two"

[loply]

Yeah ducatis use desmodromic valves which is a seperate cam that rams the valve shut. They do have springs to back it up.

Eliminates valve float (slow closure) problems at high revs.

Formula one cars use a pneumatic system to the same effect.

[Kickstart]

Hi

Yes Ducati desmo valves do stop valve bounce (think Mercedes used them years ago in GP engines), but not really sure how much of a problem that is. The CBR250 red line starts at 19500rpm and that uses normal valve springs. Honda have had race engines going higher than that with normal valve springs, and apparently had experimental engines revving to 27000 with normal valve springs. Not heard of a Ducati revving to any of those speeds. To a large extent Ducati use it for marketing reasons.

The Ducati system does use some very small springs, more just to quieten things down than to actually close the valves.

All the best

Keith
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