Im new to Denver area, been riding the local mx tracks. Jetting is dialed in, good color on spark plug, no bog anywhere. No engine mods and have stock gearing 13/48. 06 crf450r. Im really missing the low/mid range hit it had at sea level. I know these bikes suffer power loss at altitude, but whats everyone doing out here. Im thinking go up about 2 teeth in the rear and possibly and exhaust down the road. Does anybody know any quick cheap solutions?
High altitude help
Started by bda328, Jan 31 2012 07:48 PM
6 replies to this topic
Posted 31 January 2012 - 07:48 PM
Im new to Denver area, been riding the local mx tracks. Jetting is dialed in, good color on spark plug, no bog anywhere. No engine mods and have stock gearing 13/48. 06 crf450r. Im really missing the low/mid range hit it had at sea level. I know these bikes suffer power loss at altitude, but whats everyone doing out here. Im thinking go up about 2 teeth in the rear and possibly and exhaust down the road. Does anybody know any quick cheap solutions?
Posted 31 January 2012 - 08:14 PM
maybe advance the timing a bit. idk what you have access to but if you could mill the head or shave the block a little to gain some compression it might help too
Posted 01 February 2012 - 07:32 AM
A bump in compression would certainly help. It is usually done with a piston as opposed to shaving anything off. Your 06 is probably ready for a top-end anyway. Between a compression bump, a fresh topend, and going through the head, you will restore performance, probably similar to what your tired 06 did at sea level.
Posted 01 February 2012 - 02:40 PM
What is your jetting?
A 50 tooth rear sprocket will feel snappier, because it is, but a 48 will give you faster lap times on an mx track.
Altitude is a power killer.
A 50 tooth rear sprocket will feel snappier, because it is, but a 48 will give you faster lap times on an mx track.
Altitude is a power killer.
Posted 02 February 2012 - 01:01 PM
im sure my top end is tired like u guys are saying, i bought it new late in 07 so its got hours, appreciate your thoughts
Posted 02 February 2012 - 06:14 PM
Easiest thing to do is play with you pilot jet and needle position. Main jet should be 158-162 depending in temps. Go a size down on the pilot to start. I'm at 6000 feet and went down a pilot size and to a 162 for winter riding. Needle is dependant on your mods. A high comp piston will help but it is more involved than jetting, stock is 12.5 and a 13 or 13.5 will work on pump gas at elevation. Not too far off though if you know how to work on your bike. Rember you lose 3% of a hp for every 1000 feet you got up in elevation.
