CRF450X bottom end failure

[drewMember]

brass coloured metal shavings will most likely be normal steel, but because they were hot and in sump oil they will have burnished to a brass colour.

where the metal has come from will only be known once you strip it down.

[Bob DowsettMember]

jimmy wrote:

Thanks for all the quick replies! Helped me heaps already. Now who wants to buy a one lady owner crf45ox, never been raced?

Buy ……..I didn’t think anyone bought used red ones 😆

[StuartMember]

jimmy wrote:

Just had my bike blow up at the Yellow Mountain race. Its an 08 model I bought new. Regular oil changes but has done a fair amount of racing pony expresses and 3 Yellow mountain races and 1 Condo 750, so some high speed stuff.
It started missing, I pulled up, it was rattling and then it seized. I just pulled the top end down and there were no dramas, but the big end bearing is seized and the oil was full of brass coloured metal shavings. I will have to split it to see what else is stuffed.
Is this common in these 450’s? Is it worth fixing or what are the chances of finding a complete second hand motor to put in it?

Interesting………

Everyone says the CRF a stronger engine with the separate oil circuits.

My WR has done 3 Yellow Mountains, Condo 750, Finke, a bit of Hattah, & a few Condobolin Enduros one of which is similar to Yellow Mountain for terrain as well as heaps of trail riding.

Still going strong. I did a top end last year for piece of mind, should never of touched it as it was like new inside

[GregMember]

sb_250y wrote:

jimmy wrote:

Just had my bike blow up at the Yellow Mountain race. Its an 08 model I bought new. Regular oil changes but has done a fair amount of racing pony expresses and 3 Yellow mountain races and 1 Condo 750, so some high speed stuff.
It started missing, I pulled up, it was rattling and then it seized. I just pulled the top end down and there were no dramas, but the big end bearing is seized and the oil was full of brass coloured metal shavings. I will have to split it to see what else is stuffed.
Is this common in these 450’s? Is it worth fixing or what are the chances of finding a complete second hand motor to put in it?

Interesting………

Everyone says the CRF a stronger engine with the separate oil circuits.

My WR has done 3 Yellow Mountains, Condo 750, Finke, a bit of Hattah, & a few Condobolin Enduros one of which is similar to Yellow Mountain for terrain as well as heaps of trail riding.

Still going strong. I did a top end last year for piece of mind, should never of touched it as it was like new inside

Interesting ….. Not helping him fix his bike :laugh: But good on the WR and your maintenance routine mate

Top 30 Jimmy that’s fair play out there mate as there is normally some talent out there. The XRs have brass thrust washers either side of the rod on the big end reckon that’s where your metal is from mate. Actually would bet it is hope that helps with the pain. Top 30 out there would the best old bull finish I would think and sonds as though it gets the throttle twisted. On the rod kit business I just bought a Prox kit for mine was under 170 I think, Tekniks can get them if that helps

Good luck mate

TB

[James RookyardMember]

Thanks trailboss. Rain here this week so will get a bit of time to pull it all the way down. The bore still has hone marks in it. I put new rings in when the valves went at yellow Mountain 3 years ago. So I would rate the top end as bullet proof if only they had run stainless valves in them from new. As for the bottom end….. not so good.
My old 95 xr400 never missed a beat in 13 years! The CRF smokes it in all other aspects though. WR’s must be tough, but could never own a blue bike though lol! Hang on, there is a TTR 230 in the shed here.
Didnt make top 30, 60km short:angry: I got 51st last year and a DNF the first year as well. me and Yellow Mountain are not mixing to well so far.

[GregMember]

Sure thats what it will be Jimmy brass thrust washers. Good thing about the separate gearbox engine is when an engine or gearbox fails it doesnt contaminate the engine and gearbox. KTM use the same system dont know who else. Not many people know but Ben Grabham failed top gear on his CRF just out of Finke coming home whilst leading in 2007 and rode home in fourth with metal all through the gearbox. If it had the shared oil that metal would surely have got into the more sensitive main bearings and failed, he was told no more flat shifting :cheer:

Those CRFs are everywhere out west on the fast stuff, yet rare as here on the coast in the scrub.

TB

[Mick DMember]

Hey Jimmy, just so you know what you are dealing with, these diagrams may help.

[James RookyardMember]

Looks like I will have to keep it for a while longer, so has anyone used or know what the 470 stroker cranks are like? Is the extra cost worth it?

[James RookyardMember]

Anyone?????

[drewMember]

dunno Jimmy, check out thumper talk.

http://www.thumpertalk.com/forum/showthread.php?t=875375

http://www.thumpertalk.com/forum/showthread.php?t=850711

http://www.thumpertalk.com/forum/showthread.php?t=611961

there is some talk over there of extra stress on crank bearings etc.

then there seems to be reliability issues.

some research for you and some careful thinking… ask around any you know that have or mod/race/ride the 450x. those you race with etc.

[GregMember]

Jimmy I was lucky to be a small part of the Honda team at Finke in 08. The winning bike ridden by Grabbo was CRF450. We watched it be built at the workshop and at Alice from the crate. Only mods were vortex, pro circuit full system and jetting, stock head , valves cam etc. Both Chicken and Factoryphil saw it as well. Ben had his own forks and shock as well. Point being mate I reckon you will only sacrifice reliability for a performance gain you won’t get enough benefit from cause they already go hard enough. Just mine opinion

TB

[James RookyardMember]

Does this damage inside the crankcase look to terminal?

Cant upload photos, can someone tell me how please?

[Dwayne OMember]

best to load them to Photobucket account, then copy & paste the img code straight into your OBT post

Cheers

[James RookyardMember]

[James RookyardMember]

[Author]

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