When to shift?

[Capinure]

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

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]

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]

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.....:devil2:



Just talking the piss :niceone:

[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.

[wbks]

haha good to know. Do you know what I should do to maintain it besides changing oil? I've only put a new cam tensioner in.

[Capinure]

i've only taking it on one ride so far , folks wont let me ride it anymore till i get my final piece of gear ( pants ) , its "apprently" only done 13,000 but i hardly doubt it. It runs sweet as far as i know at the moment :D.

Yea, ride it like i stole it :)

[Capinure]

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

I havent ridden it hard yet , but i guess the powerband drops at around 16,000 then.

I've ridden the GSXR 250 , CBR 250RR and now i own the ninja , i notice that it feels like its got more torque then the rest of em , quite off topic sorry but just saying i like it.

[wbks]

Its your topic. I would only ever take it over 16000 when im trying to top it out on the straits in which its 5th up to 17,000 then shift. Either that or up steep hils. revving much higher is pointless though i recon. Thats freakin sweet that its got such low ks. Probably hasn't had the oil changed yet so make sure to do that as it isn't even run in yet! How much did you buy it for? Kind of a rarity to find one so new...Mine was pretty tidy when I got it for 3k with new pirellis on it but quite high ks. Yours must have been somewhere around 6, am i right?

[CM2005]

lol, those tiny engines interest me... must beg borrow steal a ride on one sometime... remember, dont let the engine bog down too much, as this damages them as much as over revving them, keep it between 5-16k RPM and you should be sweetas.

[GrayWolf]

I replied to a similar post elsewhere...... but simple really, higher the revs?? higher the wear rate! Regardless of the fact it thrives having the nuts revved off it. Thats the tuning condition of the motor to produce the performance it does. Look at life on a high revving small cc bike like owning a race bike..... thrash it constantly? repair bills loom faster. :bash: The metal used to make the engine isnt Thrashalium that has super anti breakage properties.
All bikes big or small have a sweet spot where the motor pulls well without putting the rev counter on the stop.

[wbks]

i ride mine down the street at 4k some times when im warming it up but i dont think it labors it because im only just on the throttle and it doesn't surge or make that bogging sound but then again im new to roadbikes so what do i know.

graywolf- not talking about redlining it, but it doesn't seem to make enough of a run untill 14 when you are really going hard

[Capinure]

okay i just re-newed my love hate relationship with 250 inline fours , THEY DNT LIKE TOWN RIDING , took it for its first real blat today and after 20mins in town it started missing a little in the low revs , i had to take it out of town and give it a little thrashing , runs sweet now , pulls like a motherf*** lol.

Possible needs a tune-up or just a service.

[wbks]

Sounds like what mine did when it needed the carbs balanced. Surged in the lower revs under acceleration. i.e town riding.

[Capinure]

holy sweet jebus wbks , whats your name btw mate , your my new zxr buddy man , exactly what my mates dad and my dads mate said haha (yes two different mechanics) ! good thing both can fix the problem.

They said the carbies are out and are causeing a huge miss, now i got three people to confirm it :D .

[wbks]

Kristian. Not that I'm an expert but while we are on zxr250 buisness, if you are checking it over for problems later on in the K's make sure the cam tensioner is fine. The zxr250s are kind of prone to wearing them out after quite a while because they are kind of funny in the way that they adjust themselves. Just listen for an out of the ordinary loud engine noise, it almost sounds buzzy like. Cheap to fix though and its really obvious because of the noise it makes. Happened to mine a couple thousand ks after I got it.

[Capinure]

it seems fine at the moment thanks for that info tho , i'll know the sound cause my mate has a zxr a and it macks the funny sound . took it for a blat this morning gave it a handful , its runs well in the open road , it sounds great when you open her up ae :)

[wbks]

Goes from a nice deep grunty sound to something like an F1 car, huh?

[Capinure]

hell yeah , its more high pitched then the gixxer , my neighbours hate me again

[wbks]

Thats how you know you're getting the bikes outa the shed enough. You're a real biker when they start throwing old vinyl records at you because of the noise