When to shift?

[Capinure]

Hey Guys, i manage to pick me up a 92 ZXR 250 C last night from pammy! Woohoo riding again .

Just wondering since I previously owned a 250cc I-4 before this (GSXR 250), i was wondering is it actually bad for these bike to be kept in low rev's? or should i ride it like i stole it even in town?, i didnt ride my old Gixxer in town to much cause it always felt it didnt like it too much.

Cheers KB

[MSTRS:Me]

No engine likes lugging. The smaller they are, the higher the revs need to be to work in that 'healthy' rev range.

[PirateJafa]

Valves bouncing is usually a good indication.

[DarkLord]

N00b question -

are bouncing valves the cause of that shuddering sensation when the bike is about to stall?

[MSTRS:Me]

N00b question -

are bouncing valves the cause of that shuddering sensation when the bike is about to stall?

Nope. Valves bounce when over-revved. The springs are not 'stiff' enough when subjected to such rapid compression/relax.

[vifferman]

N00b question -

are bouncing valves the cause of that shuddering sensation when the bike is about to stall?

No.
Valve bounce only happens at high revs, when the valves are going so fast they're bouncing off their seats instead of staying seated there till the next time they're opened.
"That shuddering sensation" is caused by the engine operating at too low a revs, so that it's producing insufficient torque for the speed you're traveling at and the gear you're using. The force produced by the expansion of burning fuel in the combustion chamber just isn't enough to propel the bike forward.

[Weaver]

Way to slow in typing my reply

[vtec]

It's fine to run these engines at any speed above idle. But if you are going to full throttle it, do so above 9000rpm. Below that you will probably find that partial throttle is actually faster. Cruising at 5000rpm is fine in top gear at 55kph is fine. This is from CBR experience, I'm guessing the gearing on the ZXR is similar.

It's actually pretty hard to do anything bad to these engines. Apart from free revving a lot, or dropping the clutch from high revs. The are strong little bastards.

I personally think the shuddering when running at revs below idle could be bad for it and would advise against it, but it's rare to do any damage.

[Capinure]

Cheers Guys , thanks for your info , i just get told by some people that riding it like a nana is bad for it thats all.

[wbks]

just a quick topic related Q for myself and I'm sure capinure would like to know as well...Is it bad to ride when warmed up of course at 12,000-16000 revs constantly (not cruzing, going hard) or topping it out on straits? Or to sum it up high revs but not redlining it? I don't redline it because it has a very noticable power drop off after about 16, 000rpm btw

[AllanB]

it has a very noticable power drop off after about 16, 000rpm btw

Try that on a Harley test ride ........ let us know how it goes.....



Just talking the piss

[wbks]

rode a 1200 sportster once...got the talk about not riding it like a sportsbike when i got back haha

[AllanB]

rode a 1200 sportster once...got the talk about not riding it like a sportsbike when i got back haha

Yep - pointless revving the crap out of one - those motors are sweet in the low and mid range. Heck a big-bore Hog is making good pulling power at the same revs these 250fours idle at!!!!!!!!

[wbks]

It wasn't so much that I was revving it too high(well that too) but you know how hog riders go...rev-clutch in wait 5 min then shift...i was shifting faster than most and revving it hard haha im not a good harley person.

[lostinflyz]

just a quick topic related Q for myself and I'm sure capinure would like to know as well...Is it bad to ride when warmed up of course at 12,000-16000 revs constantly (not cruzing, going hard) or topping it out on straits? Or to sum it up high revs but not redlining it? I don't redline it because it has a very noticable power drop off after about 16, 000rpm btw

ride em hard. everyone else would have that owned the bike previous. so long as they are maintained well and not stuffed already and eveything is as it should be theres no harm in giving them the beans. they dont make all that nice power in the upper revs so you can stare at the dyno charts.