Wr Crank Is The Sh&%$

[motomanmike]

After a recent cylinder head failure, i decided to totally rebuild my engine. I talked to a very helpful fellow named Jay at BCS performance, he hooked me up with a crank and piston from a WR 450 and did the oil mod on my cases and i just gotta say, THIS THING RIPS. So much more bottom end along with just the power you need when you need it. Feels like a totally different quad. I highly recommend the WR crank over stock YFZ any day.


Anyone else??

[hoser 400ex]

had the wr crank in mine. as well as the oil mods. broke the wrist pin on piston, causing crank to break. now am putting in the 06 crank. a lil more heavy duty!!!

[YFZ450 11x]

I also had Jay from BCS do mine:D I had some tranny probs so while the cases were apart I thought why not get a couple more ponnies. Man this thing rips!!! I also had him do a port and polish and a 13:1 cp piston. I threw the boysen Quick shot on too.
Hey man what are you running for jetting?
heres a pic



http://www.upload-picture.com/images/0i688691.jpg

[motomanmike]

Ha jetting so much fun. We played with every possible combination. New needles all kinds of jets, needles in all positions. The best i have come up with mine is a 180 main jet, stock pilot from an 04 and the stock needle from the 04 on the second clip from the bottom. its not perfect but its pretty damn close. i need the boyensen quick shot i think that would fix everything else FCR's like to bog when you crack them too hard but with the 180 main it pulls the hardest out of all my jets i tried. It is very snappy. I'm running 115 octane, half and half with 92 octane gas. We tried from a 165 to a 200 in all needle positions. I am at sea level. Thats a NICE YFZ, i want some HYPERS so bad. What do you think of BCS? Jay was soooooo helpful, i called him a few times with the assembly and he's just so down to earth. I will definetly do business with them for a loooooong time. Quick turn around too.

[ssmith]

Hi,
I have the WR450F crank, but I can't find the WR450R piston, does anyone know where I can find this?
Thanks

[beastlyone]

hey man about how much did you pay to have your engine completely rebuilt by BCS? also do they have a website with pricing etc..

[ZRider400]

www.bcsperformance.com

[Ride1Rob]

Originally posted by ssmith
Hi,
I have the WR450F crank, but I can't find the WR450R piston, does anyone know where I can find this?
Thanks

They sell them on E bay. They have a few JE High comp pistons for $140's plus.

[motomanmike]

sorry dude its the wr450f piston too i have it listed wrong on my parts list. i got all my stuff from bcs. I appologize for any confusion i will fix this pronto

[TWILES]

I have a 2005 WR450. I don't know much about the older YFZ's other than they are actually 440's and that the stroke is different from the bike motors to the point that you have to bore them to make them 450's...so i've heard. I know the WR makes a lot more power than even the 450cc YFZ's. If you have the older 440cc YFZ's, can you not put the WR crank in the in the older bottom-end and then use the WR 450 cylinder, head and everything else and basically have the WR motor?

[Bill Fuller]

I have the WR kit in my '04 as well.I love it,you can't beat this mod for $400.

[Ride1Rob]

Originally posted by TWILES
I have a 2005 WR450. I don't know much about the older YFZ's other than they are actually 440's and that the stroke is different from the bike motors to the point that you have to bore them to make them 450's...so i've heard. I know the WR makes a lot more power than even the 450cc YFZ's. If you have the older 440cc YFZ's, can you not put the WR crank in the in the older bottom-end and then use the WR 450 cylinder, head and everything else and basically have the WR motor?

You don't have to bore to make it a true 450. That's what putting the WR crank in it does. It makes the stroke longer thus making the bike 450cc's. And all you need to do is to put the WR crank in and a piston that's compatible with it and THAT'S IT!

[ssmith]

thanks guys i found one on ebay for $140

[Bill Fuller]

While inside make sure to replace the crank bearings and timing chain.I would also recommend replaceing the coolant impeller(sp)and seals.Now is also a great time to check your valve shim clearance.Inspect your cylinder and have it relined or buy a new one.I found one on Ebay for $200 plus or minus.I would also do the oil mod.Once you understand what it does,you will know that it can only help.Make sure to get all the gaskets you will need.Checking or doing all the above will save you trouble in the long and short time.Why spend all that time and money only to have to go back in the following weekend,or be stuck waiting for parts.

[ssmith]

im doing the whole rebuild by myself because when i got the yfz the bottom end was blown but where do i find how to do the oil mod?

[Bill Fuller]

There are many threads about it on www.yfzcentral.com and www.yfztech.com use the search.

[ssmith]

thanks that helped alot it gave me pics and every thing i might beable to do it my self to because im going to school for machining

[ssmith]

if i cant do it myself where do you recomend i sent it and do you have any idea howmuch it will cost me?

[Bill Fuller]

Again check these sites and search.If you have some basic tool and die training you can do this yourself.I used a 1/16 bit for the squirter hole,and a hand drill.As far as behind the filter,I don't remember.You will also need to cut a groove for an O ring to sit to form a seal between the cases.I used an O ring from the oil filter cover (new) and a square shoulder bit and just barely made a cut(about half the thickness of the O ring.I think Sparks will do the mod for you for around $65 plus shipping.

[ssmith]

sounds easy enough i think i can handle it thanks for all the help

[ssmith]

when you put the wr crank and piston in did u have to rejet i know im gunna have to because im putting in the wr crank and a 13:5:1 high compression piston and the head is being ported and im putting an exhaust on it

[Bill Fuller]

I did not have to rejet.With the other mods you are doing it would be a sure bet that you will need to rejet.

[MET]

For those looking for pistons for use with the WR crank conversion, you can use any piston from the 2003-2006 YZ450F and WR 450's,the pistons are the same and use the smaller 18mm wristpin. I peronally don't suggest using above a 97mm piston on the small 18mm wristpin. Wiseco,JE,CP and a few others make YZ pistons. If you plan on running above 13:1, I would use pistons made by CP,they have a good dome design for high compression.

[MET]

Originally posted by ssmith
when you put the wr crank and piston in did u have to rejet i know im gunna have to because im putting in the wr crank and a 13:5:1 high compression piston and the head is being ported and im putting an exhaust on it

On my race engine at 13.8:1, I use the following:
MJ: 175-180
NCVQ #3-4 clip
Pilot #45
F.S. 1.5-2.0 turns out
Leakjet #55
Boyesen A.P cover
FCI intake, w/airbox, no lid
Fuel motor octane 103-104
Ngk CR9EiX
tested at sea level,about 70degF
Again this is a true 450 race engine,ported,+1mm valves,cams...

[2muchquad]

If you plan on running above 13:1, I would use pistons made by CP,they have a good dome design for high compression

I have been using a wiseco 13.5 comp piston for a long time now,no problems.;)

[ssmith]

hey does any one know if the yz450f piston is the same as the wr450f piston???