Getting a new bike

[honda8&3]

Well I just put a down payment on an 07 crf450r, and I'm kinda new to maintaining these bikes. I'm obviously gonna run synthetic, but what should I run? I'm prolly gonna go amsoil but what weight?

[Z15]

You can use either a 10W-30 or 10W-40 engine oil. I would recommend you go by what the preferred grade is in your owners manual.

10W-30 Synthetic Motorcycle Oil (http://www.amsoil.com/catalog.aspx?GroupID=742&zo=34396)

10W-40 Synthetic Motorcycle Oil (http://www.amsoil.com/catalog.aspx?GroupID=168&zo=34396) <---- When I doubt, use this grade

Shown on page 7 in the Online AMSOIL Catalog (http://www.amsoil.com/lit/g100/g100.aspx?zo=34396)

[KXRida]

check your valves every 20 hours or so and shim them as needed. Do FREQUENT oil, oil filter, and air filter changes. Best thing you can do for a high compression 4 stroker. Personally, I run a "cheaper" oil and change it often. Right now though I have maxima ult. 4 in it, but normally, I run rotella T and change it every other ride, do an oil filter change every other oil change, and clean the filter after every ride or two. Rotella T seems to be pretty big right now with a lot of people and is frequently talked about. I used it since day one when I had my yzf without any issues. Walmart had a 2 gallon jug for like $25 so the price is right and you can change it often.

[user101]

What about the bottom end. Ive noticed alot of bikes will only be a year or two old and already have a new crank. Are the cranks weak?

[k4f5x0r]

That is mostly with 250f's generally because they rev at 11k+ rpm. The cranks go out quicker with them then in the 450's because you NEED to rev for any decent power.


Everyone really covered it. I change my oil every other ride, oil filter every other oil change, and i clean my air filter when it looks like it needs to be cleaned.

[jesseweaver]

Originally posted by k4f5x0r
That is mostly with 250f's generally because they rev at 11k+ rpm. The cranks go out quicker with them then in the 450's because you NEED to rev for any decent power.



:confused: i easily pulled on piped and filtered trx's and yfz's when my 250f was stock. everyone underestimates them so much because its only a 250

[user101]

Yea, these 250's are stout. I rode one last summer and i know it pulled harder than my 450.

How many hours can u get out of the stock crank before it needs replacing. Are there any early signs to tell if the crank is gettin weak or does it just decide to go and tear all kinds of $h!t up.

[k4f5x0r]

Originally posted by jesseweaver
:confused: i easily pulled on piped and filtered trx's and yfz's when my 250f was stock. everyone underestimates them so much because its only a 250


I wasn't saying they were slow by any means. What i meant was that the majority of their power is made in the higher range of its power curve.

example: my KTM makes peak power at about 9 thousand(out of 11,500) RPM's.

It also has about 38 horsepower(same as my kfx450 stock) :devil:

[jesseweaver]

Originally posted by k4f5x0r
I wasn't saying they were slow by any means. What i meant was that the majority of their power is made in the higher range of its power curve.

example: my KTM makes peak power at about 9 thousand(out of 11,500) RPM's.

It also has about 38 horsepower(same as my kfx450 stock) :devil:

yea the bikes do put down some really good power. thats why i'd love to sometime be able to ride a factory 450 :devil: i can't even imagine how fast they'd be. i hear the factory 250s are pretty much faster than any built 450 you see at local races

[k4f5x0r]

I cant even imagine the amount of horsepower the factory 450 bikes are putting down:eek2: . I was always curious to how much they run, because i think there has to be limit eventually.

The factory 250's probably only make a fraction less then the factory 450's, they just make it in a very different area.

[KXRida]

A factory 250f puts out about 50 hp or so which is equivilant to a mostly stock 450. Factory 450's are putting out upwards of 75hp outdoor and most seem to average around 68 for indoors. Either way they're pretty much a one race motor.

[Canadian144]

Originally posted by k4f5x0r
example: my KTM makes peak power at about 9 thousand(out of 11,500) RPM's.

It also has about 38 horsepower(same as my kfx450 stock) :devil:

Those SX250-F are pretty quick haha.... my friend used to have one, in a drag race he would always beat me and my friend who had a WR250F.

He sold it to buy a truck which he then traded for a CBR125 (lol). Now he wants to get another bike... I think he wants an SX150 or some smaller cc two stroke.

[honda8&3]

Thanks for the comments guys, I'm still undecided though. I've been hearing of a lot of people using rotella t, and I know for trucks the stuff is great. I joined thumpertalk too so I dunno yet. I'll have to look into everything thanks though

[Jake250ex]

Originally posted by KXRida
A factory 250f puts out about 50 hp or so which is equivilant to a mostly stock 450. Factory 450's are putting out upwards of 75hp outdoor and most seem to average around 68 for indoors. Either way they're pretty much a one race motor.

a stock 450 puts out high 30's, and im not the bike expert but on thumpertalk everyone rated stock 250f's around 35hp...

[jesseweaver]

Originally posted by Jake250ex
a stock 450 puts out high 30's, and im not the bike expert but on thumpertalk everyone rated stock 250f's around 35hp...

he means factory-backed race bikes not bikes that come from the factory

[KXRida]

Originally posted by Jake250ex
a stock 450 puts out high 30's, and im not the bike expert but on thumpertalk everyone rated stock 250f's around 35hp...


loooool so wait, you're saying a stock 450 puts out high 30's in HP and a stock 250F puts out 35hp? Something seriously wrong with that picture there!
By factory, I'm meaning factory backed race teams with unlimited budgets. It's not unusual for some of their 250F motors to get close to or eclipse the 50hp mark.

[Jake250ex]

oh i gotcha. i thought by factory you meant stock. yeah, a stock 450r QUAD puts out mid-high 30's on a dyno

[backwoodsracer]

follow the manual snthetic or not, Nobody knows the bike better than the people who made it!

[fastredrider44]

I recently switched from GN4 to Rotella in both sides of my 450r. Nothing to note other than I have more money in my pocket.:p

[KFX450Rrider490]

Originally posted by fastredrider44
I recently switched from GN4 to Rotella in both sides of my 450r. Nothing to note other than I have more money in my pocket.:p

same here and the great part is ive got a 55 gallon drum of it!!!

[honda8&3]

I think I may just switch to Rotella t first oil change. Got a lot on my mind now haha :D

[John Noftsinger]

It,s the weight that make,s it faster than a 450 quad ,in the woods i can run with any 250f but when the you get to straight away they pull away cause there 150pds lighter big difference when it come,s too acceleration I wonder if you put both on dyno and put the weight of quad on dirtbike what would it read on dyno?Would the extra load (weight) lower the 250f #,s alot?

[trx310R#24]

Originally posted by KFX450Rrider490
same here and the great part is ive got a 55 gallon drum of it!!!

wow lol

[TRXman86]

Originally posted by jesseweaver
:confused: i easily pulled on piped and filtered trx's and yfz's when my 250f was stock. everyone underestimates them so much because its only a 250

You do realize that bike's take off faster and are overall quicker (most generally) any way right?