Big Bore crf450?

Crazyhonda · 08-27-2006, 06:31 AM

Has anyone done this or know any information. I was considering it for my bike but I dont know if it will be worth the time and effort. I love my crf just looking for a little more power!

IronHorse · 08-27-2006, 02:06 PM

I personally haven't done it but if i were you i would check out the mags. They do lots of test on bigger bores and stuff.

Specifically i think Dirt Rider does the most test on things like that.

tigmaster · 08-28-2006, 06:12 AM

Even if its not a kit u def can jus get it bored, theres plenty of sleeve meat to go up a bit but if yur lookin for like an extra 50cc then u might need to resleeve. also u could always go for the mill of the head or u could stroke it a bit, dont no want yur clearances are, their overhead valves arent they.

mx4fun · 08-28-2006, 10:52 PM

You can get a big-bore, but you have to remember the reliablity will go down. I had a friend put a 490cc into his 05 crf450, and the bike blew in 3 months. He prob. wasent putting oil in it or something, lol. Just don't go to big, lol.

tigmaster · 08-29-2006, 06:09 PM

did his bike blow a head gasket or wat. cuz as far as reliability u wont have a prob with a kit or doin it yurself. u can either bore the sleeve sum or pull the sleeve and bore it out alot then drop in a bigger sleeve. if u bore the sleeve u can get it plated with nikasil for added fancyness and it allows u to use a diff type of head gasket when u use nikasil, meaning yull never blow a head gasket again

dirtbikenut · 01-01-2007, 08:10 PM

I bought the bike that MX was talking about. What happened is that he was hard on the clutch and the clutch plates tore apart and then lodged in the water pump; it them heated up and seized. At least that is what I know!
It was find after he put it back to stock, but I think that this pblm was a strange anomoly. MX did ride that bike with the big bore and he said that it was SCARY FAST!!

Go Get It and have fun!!

tigmaster · 01-01-2007, 10:54 PM

How did u mange to get parts of your clutch into your coolant system? r u talkin bout the waterpump gear or the actual impeller? also the impeller gear comes right off the crank and if clutch parts were wedged in there, yur engine wouldnt be workin too well. idk, but if u stall anything related to your coolant system then u are most likely stalling yur engine unless u shear a shaft or some gear teath off.

08-27-2006, 06:31 AM	#1 (permalink)
Crazyhonda C Rider Join Date: Aug 2006 Posts: 4 iTrader: (0)	Big Bore crf450? Has anyone done this or know any information. I was considering it for my bike but I dont know if it will be worth the time and effort. I love my crf just looking for a little more power!

08-28-2006, 06:12 AM	#3 (permalink)
tigmaster Administrator Join Date: Aug 2006 Location: Missouri, United States Posts: 7,659 iTrader: (1)	u could get it bored either way Even if its not a kit u def can jus get it bored, theres plenty of sleeve meat to go up a bit but if yur lookin for like an extra 50cc then u might need to resleeve. also u could always go for the mill of the head or u could stroke it a bit, dont no want yur clearances are, their overhead valves arent they.

08-29-2006, 06:09 PM	#5 (permalink)
tigmaster Administrator Join Date: Aug 2006 Location: Missouri, United States Posts: 7,659 iTrader: (1)	wat do u mean did his bike blow a head gasket or wat. cuz as far as reliability u wont have a prob with a kit or doin it yurself. u can either bore the sleeve sum or pull the sleeve and bore it out alot then drop in a bigger sleeve. if u bore the sleeve u can get it plated with nikasil for added fancyness and it allows u to use a diff type of head gasket when u use nikasil, meaning yull never blow a head gasket again

01-01-2007, 10:54 PM	#7 (permalink)
tigmaster Administrator Join Date: Aug 2006 Location: Missouri, United States Posts: 7,659 iTrader: (1)	What? How did u mange to get parts of your clutch into your coolant system? r u talkin bout the waterpump gear or the actual impeller? also the impeller gear comes right off the crank and if clutch parts were wedged in there, yur engine wouldnt be workin too well. idk, but if u stall anything related to your coolant system then u are most likely stalling yur engine unless u shear a shaft or some gear teath off. __________________ --'03 CRF450r-- --FMF Pipe, Pro-Tech Revavle-- --Vortex Basket With Tusk Disks And HP Springs-- --Pro Taper Triple Clamps And Bars-- --Devol Full SP With Moose HGs-- --Renthal 13/50 With R1 Chain-- --Now It Is The End, Probably...-- --'06 CBR F4I-- --Bone Stock-- Check Our Latest How-To Here Last edited by tigmaster; 01-01-2007 at 10:57 PM.

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08-27-2006, 02:06 PM	#2 (permalink)
IronHorse C Rider Join Date: Aug 2006 Posts: 4 iTrader: (0)	I personally haven't done it but if i were you i would check out the mags. They do lots of test on bigger bores and stuff. Specifically i think Dirt Rider does the most test on things like that.

08-28-2006, 10:52 PM	#4 (permalink)
mx4fun C Rider Join Date: Aug 2006 Location: Nor. Cal Posts: 33 iTrader: (0)	You can get a big-bore, but you have to remember the reliablity will go down. I had a friend put a 490cc into his 05 crf450, and the bike blew in 3 months. He prob. wasent putting oil in it or something, lol. Just don't go to big, lol.

01-01-2007, 08:10 PM	#6 (permalink)
dirtbikenut C Rider Join Date: Aug 2006 Posts: 43 iTrader: (0)	I bought the bike that MX was talking about. What happened is that he was hard on the clutch and the clutch plates tore apart and then lodged in the water pump; it them heated up and seized. At least that is what I know! It was find after he put it back to stock, but I think that this pblm was a strange anomoly. MX did ride that bike with the big bore and he said that it was SCARY FAST!! Go Get It and have fun!!

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