ferg Posted October 22, 2011 Report Share Posted October 22, 2011 I love motocross bikes. I used to race but haven't for years and although I still have my old '98 YZ 125 it's in need of lots of money being thrown at it. Mx bikes are pricey but they are in a different league in comparison to trail bikes. What I've been thinking about recently is a way to bring the two together; keeping the reliability and less frenetic nature of a trail bike but also have the top end chassis components and light weight fun of the 'cosser. Would it be possible to retune (detune) a 450 to make it more reliable and less maintenance heavy? A 450 has a huge amount of power anyway so a slight drop wouldn't be the end of the world. The difference in a £500 or £1000 rebuild bill every year would though! Is this possible? In my head I've been thinking of lowering compression or perhaps a less aggressive cam profile. Can anyone with a proper mechanical brain add to this? Would it be possible? What would you have to change? Link to comment Share on other sites More sharing options...
tootall Posted October 22, 2011 Report Share Posted October 22, 2011 Are the 450 enduro bikes not at a slightly detuned spec already? May be a way forward. Link to comment Share on other sites More sharing options...
ferg Posted October 22, 2011 Author Report Share Posted October 22, 2011 I was always under the impression that if they were the proper race enduro bikes, then all they had was a different tune for a more even spread of power throughout the range? So near enough the same service intervals? I've only been around mx bikes though so have no real clue... Link to comment Share on other sites More sharing options...
Alex_H Posted October 22, 2011 Report Share Posted October 22, 2011 The enduro bikes have longer boxes normally too. It might be easier to get a 450/250mx chassis and stuff in an engine with a service interval that suits you maybe? CRM engine into crf frame for example, drz motor into rm... Link to comment Share on other sites More sharing options...
Alex_H Posted October 22, 2011 Report Share Posted October 22, 2011 multiple god damn post, sorry Link to comment Share on other sites More sharing options...
ferg Posted October 22, 2011 Author Report Share Posted October 22, 2011 Did some looking and regarding the CRF 450X... bugger was planning to cut and paste but it's disabled, reading here Basically it's still a change the piston job every fifteen hours at race pace or ridden in a more genteel manner, every fifty hours. The engine swap is an interesting one but seems a waste of a 'better' engine. Was speaking to my dad about it tonight and he was thinking the opposite, chucking the good suspension onto a trail bike. However you still then have the poorer chassis, ergonomics and weight! Link to comment Share on other sites More sharing options...
wavydavy Posted October 23, 2011 Report Share Posted October 23, 2011 If you're looking at detuning the engine to get it reliable enough to last, say, 90 hours/a few thousand miles then its kind of a 'waste' in the same sense as its a 'waste' to just swap engines for a lower spec lump..... I know they're not exactly a shining example of reliability, but the Aprilia v-twins (like mine... ) have the MXV-spec crosser as well as the R/SXV road-legal versions which, as homologated, are only rated to about 20bhp at 4500rpm or something very silly like that. Just pegging revs to 10,000 (as I do) instead of 12,000rpm keeps top-end servicing down to 90hrs instead of 19, so limiting yourself to 8,0000rpm might be enough to extend the engine life to something fairly reasonable, whilst still have very high spec chassis and suspension components.... Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.