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Re: warming up ur zxr400

Posted: Sat Feb 02, 2008 7:35 am
by deviant
Scott221 wrote:
crushedlizard wrote: either sits at a gentle 1200 or screams at 4000+ Think my choke cable needs oiling...

Nah mate, its the same with all of them, they have a stupidly high revving choke. Ah well, wakes the neighbours up nicely in the mornings :D
so it seems at first, but after you've had one for a few years you develop a sort of zen mastery of the choke, allowing you to actually find the 'half choke' position.

Re: warming up ur zxr400

Posted: Sat Feb 02, 2008 9:39 am
by Caz
rene wrote:a good point to make about warming up...alot of poeple will keep the rev's as low as possible (ie below 3,000 rpm). At tho kids of speeds your putting the bottom end, gearbox ect under masive strain, its far better to keep the bike in higher RPM with its reving alot more freely
er.........
...............um..........

I'm interested in your reasoning behind saying this......

Re: warming up ur zxr400

Posted: Sat Feb 02, 2008 10:02 am
by rene
Caz wrote:
rene wrote:a good point to make about warming up...alot of poeple will keep the rev's as low as possible (ie below 3,000 rpm). At tho kids of speeds your putting the bottom end, gearbox ect under masive strain, its far better to keep the bike in higher RPM with its reving alot more freely
er.........
...............um..........

I'm interested in your reasoning behind saying this......
Its the same as when your on a push bike if you start going up a hill and put it in the lowest gear possible your going to be working VERY hard whats going to wear you out alot faster than havinging your legs turning abit faster is far easyer. Its the same for a engine.

Re: warming up ur zxr400

Posted: Sat Feb 02, 2008 12:15 pm
by crushedlizard
deviant wrote:
Scott221 wrote:
crushedlizard wrote: either sits at a gentle 1200 or screams at 4000+ Think my choke cable needs oiling...

Nah mate, its the same with all of them, they have a stupidly high revving choke. Ah well, wakes the neighbours up nicely in the mornings :D
so it seems at first, but after you've had one for a few years you develop a sort of zen mastery of the choke, allowing you to actually find the 'half choke' position.
Haha, I always assumed my cable was just gunked up. I know what you mean, I find if I move it back by a few microns, I can find a few degrees of adjustment.

Makes me wonder though; clearly Kawasaki's theory is to just let it sit at 4000. Sometimes I let it do it as 4k is pretty low when compared to it's 14.5k ceiling.

Re: warming up ur zxr400

Posted: Sat Feb 02, 2008 12:18 pm
by zxr_oli
deviant wrote:
Scott221 wrote:
crushedlizard wrote: either sits at a gentle 1200 or screams at 4000+ Think my choke cable needs oiling...

Nah mate, its the same with all of them, they have a stupidly high revving choke. Ah well, wakes the neighbours up nicely in the mornings :D
so it seems at first, but after you've had one for a few years you develop a sort of zen mastery of the choke, allowing you to actually find the 'half choke' position.
I found it after a couple of months :smt005

Re: warming up ur zxr400

Posted: Sat Feb 02, 2008 7:25 pm
by Jamz
crushedlizard wrote: Haha, I always assumed my cable was just gunked up. I know what you mean, I find if I move it back by a few microns, I can find a few degrees of adjustment.

Makes me wonder though; clearly Kawasaki's theory is to just let it sit at 4000. Sometimes I let it do it as 4k is pretty low when compared to it's 14.5k ceiling.

I think it's just a Kawasaki thing - at least on pre-2000 models.

I think a fully open choke on my 400 was more like 6,000 too? Even my 9 takes it to 4000 and that redlines at about 11,000rpm!

Re: warming up ur zxr400

Posted: Sat Feb 02, 2008 7:27 pm
by rene
the 750 is the same in that department, you need to have it on full to get it started then quickly roll it forward to lower the rev's takes a while to get used to it but once you've done it a few times you learn were it need to be so that it dosnt stall/rev the blocks off it

Re: warming up ur zxr400

Posted: Sat Feb 02, 2008 8:57 pm
by rover220
its not so much about keeping the revs off when its cold, more keeping the load off the engine.

Re: warming up ur zxr400

Posted: Sat Feb 02, 2008 10:56 pm
by Xphyral
rover220 wrote:its not so much about keeping the revs off when its cold, more keeping the load off the engine.
warming an engine up is all about keeping revs off when cold, the engine even when warm shouldnt be put under excessive load, IE trying to pull off in 4th. cold metal is brittle compared to hot metal that has expanded to it's tolerances and cold metal parts shouldnt be put through the ringer by revving the nuts off it, . Although to be quite honest for bikes made from the end of the 80's onwards it's really not an issue riding your "road" bike hard while the engines cold, metallurgy and machining got a lot better and unless you've got a very expensive tuned race engine your not going to do much more than increase the amount of wear on the engine by a small amount(2minute cold redlines not counted).

Re: warming up ur zxr400

Posted: Sun Feb 03, 2008 9:50 am
by Caz
rene wrote: Its the same as when your on a push bike if you start going up a hill and put it in the lowest gear possible your going to be working VERY hard whats going to wear you out alot faster than havinging your legs turning abit faster is far easyer. Its the same for a engine.
First of all, that's not a good comparison. But, you have made a very good point about putting load on the engine. You are making the engine work harder by riding in too high a gear for the speed you are doing. But, providing you are in the correct gear for the speed you are doing, you are not putting any more strain on the engine by riding at lower revs than higher ones.

FWIW, we warm our development engines up for a considerable length of time before we start putting maximum load on the engine; gradually increasing load and speed.

I apply the same logic to my bike, make sure I am in the correct gear for the speed im doing and I keep the revs down to start off with.

That said, modern engines are that good and really don't need to be warmed up for 'normal' riding. I just cant bring myself to thrash a cold engine

the BMW manuals actually state that you should ride off as soon as you start the bike. BUT you should not put any load on the engine until it has reached operating temperature,

Re: warming up ur zxr400

Posted: Sun Feb 03, 2008 4:11 pm
by crushedlizard
Caz wrote:the BMW manuals actually state that you should ride off as soon as you start the bike. BUT you should not put any load on the engine until it has reached operating temperature,
Yeah a lot of car manuals say the same. I think it's to avoid excessive idling.

Basically, don't redline it straight away and don't go clicking up through the gears putting strain on the engine.