I am a 56 year old who started riding last year to spend more time with my teenage son ... I am 180 lbs, 6' tall and of average strength ... facts that will become pertinant later.
Purchased a new 02 CRF-450R in June of last year and had it modified to make it more amenable to Michigan trails which are mostly sand and mud [see list at end of post]. Being considerably anal but not extremely mechanical, I maintained the bike scrupulously with regard to cleanliness, air filter maintenance, chain tension & cleanliness, engine & transmission oil changes, and general lubrication of the moving external parts. After approximately 200 hrs operation the bike suddenly wouldn't start ... the local Honda dealer explained that the valves [intake only] were 'closed' due the fact that I did not monitor and properly adjust the lash with appropriately sized shims. They managed to reshim them and told me to monitor them at least every 30 hrs operating time thereafter. After approximately 25 hrs additional run time the bike again would not start and a check of the lash indicated they were totally closed again. This time they replaced both intake valves with brand new Titanium ones, rebuilt the top end with new piston, rings & associated components and told me to continue the valve lash monitoring routine every 15 hrs or so. Because this situation appeared to be worsening, and runtime seemed to be an extremely critical data point, I installed a SenDec motor meter to accurately keep track of the run time. A check of the valves at 10 hrs showed no change in valve lash from spec ... however at 21 hrs both intakes were down 0.003" so I purchased appropriate shims to reset to factory spec. At 30 hrs runtime a check indicated both intakes to be down 0.005" [essentially closed again] ... so I returned to the Honda dealer for help. They said that Honda believed this problem to be due to dirt intake into the engine and that I needed to replace both the head and the valves which would cure the problem ... because this seemed extemely expensive and likely to result in the same problem again if dirt really was the problem ... I began researching and found this site and the answers posted herein.
I'm still not out the woods yet though, as my dealer again spoke with Honda and they did indicate that installation of steel valves would not jeopardize the bike's longevity or performance characteristics but they did not inform the dealer that different springs would be needed for the steel valves ... so they installed standard Honda springs with my new Kibblewhite valves [by the way all four valves were changed at this time at the suggestion of the dealler ... also rebuilt the top end again with new piston, rings, etc].
On getting my bike back, the dealer noted that the engine is now very noisy [internal noise from the top end of the motor ... not present before latest work] and the resistance against the kick starter is now dramatically increased. It is at this point that I took my Honda dealer the data posted herein regarding CRF valve problems, along with the MXOffroad.com Project CRF-450 article regarding installation of the complete Kibblewhite kit and had them read the information. Next I had them order the appropriate valve spring kit from Kibblewhite and it the engine will be torn down again to replace these components.
What bothers me the most about all this trouble is that I love riding my CRF ... it is the perfect "old man's" bike ... relatively light, hugely powerful to meet any demand and not difficult to ride by those possessing less than professional skills. However, at this point in the story, the modifications done to correct the valve problems have resulted in a dramatic increase in the kick start resistance ... to the point that I cannot kick through with sufficient intensity to start the motor reliably. Up to this point I have easily been sufficiently strong to kick the bike with no problems ... I have over 250 hrs riding time, mostly by myself, and have never had trouble kicking through the start cycle until now.
Of course, my Honda dealer can start the bike with no problem [naturally, he's a big guy pushing 230 lbs or so] and they look at me like I'm getting senile or in need of a Bow Flex ...
Well, if anyone has spent the time to read through this 'horror' story ... I'm looking for some opinions and advice. I put more than 2 K-bucks into this bike when it was new upgrading and altering the componentry to make it a worthy trail bike for Michigan conditions with the thought that I would get several years enjoyment out of it before wearing out the motor or some other important and expensive part. Now this dream doesn't seem to hold much water ...
Considering that similar valve changes and piston/ring changes in the past did not alter the kick start resistance ... why has it changed so dramatically now?
I am not expecting the kick start resistance to change much once the proper Kibblewihite vavle spring kit is installed ... right?
Is it possible the decompression lobe on the cam is not functioning correctly and is causing the loud top end noise as well as the increase in kick start resistance?
Anything else that I might look into regarding the kick start resistance and ways to reduce it back to normal?
Thanks in advance for any help that folks might lend to me on this matter. Please don't think I am complaining about my Honda dealer ... they have sold less than ten CRF-450s since they came out in 2002 and all but mine were to motocrossers who race them and more importantly, do their own engine work ... hence the dealer never sees them except for ordering parts occasionally. I am their best service customer with a CRF-450 and they're cutting me considerable slack with regard to service charges for the work as they really have no experience.
Terry Nestrick
2002 CRF-450R
Scott's triple clamp/Pro-Taper bars/steering stabilizer combo
Scott's Shark Fin
Scott's modified forks/shock/springs for 200 lb rider off road
Works Connection Pro-Perch adj Clutch with Hot Start lever
Arc brake lever assembly
Moose bark buster hand guards
Regina O-ring chain
Renthal 52 tooth rear sproket
BRP billet chain guide
PC Racing Air Filter housing kit
Twin Air Filters & Blue filter oil
ZipTy Fuel Mixture adj screw
BRP spark arrestor muffler cap for stock exhaust
CEET tall form foam with gripper seat cover
Works Connection radiator/shroud braces
Works Connection enduro skid plate
Purchased a new 02 CRF-450R in June of last year and had it modified to make it more amenable to Michigan trails which are mostly sand and mud [see list at end of post]. Being considerably anal but not extremely mechanical, I maintained the bike scrupulously with regard to cleanliness, air filter maintenance, chain tension & cleanliness, engine & transmission oil changes, and general lubrication of the moving external parts. After approximately 200 hrs operation the bike suddenly wouldn't start ... the local Honda dealer explained that the valves [intake only] were 'closed' due the fact that I did not monitor and properly adjust the lash with appropriately sized shims. They managed to reshim them and told me to monitor them at least every 30 hrs operating time thereafter. After approximately 25 hrs additional run time the bike again would not start and a check of the lash indicated they were totally closed again. This time they replaced both intake valves with brand new Titanium ones, rebuilt the top end with new piston, rings & associated components and told me to continue the valve lash monitoring routine every 15 hrs or so. Because this situation appeared to be worsening, and runtime seemed to be an extremely critical data point, I installed a SenDec motor meter to accurately keep track of the run time. A check of the valves at 10 hrs showed no change in valve lash from spec ... however at 21 hrs both intakes were down 0.003" so I purchased appropriate shims to reset to factory spec. At 30 hrs runtime a check indicated both intakes to be down 0.005" [essentially closed again] ... so I returned to the Honda dealer for help. They said that Honda believed this problem to be due to dirt intake into the engine and that I needed to replace both the head and the valves which would cure the problem ... because this seemed extemely expensive and likely to result in the same problem again if dirt really was the problem ... I began researching and found this site and the answers posted herein.
I'm still not out the woods yet though, as my dealer again spoke with Honda and they did indicate that installation of steel valves would not jeopardize the bike's longevity or performance characteristics but they did not inform the dealer that different springs would be needed for the steel valves ... so they installed standard Honda springs with my new Kibblewhite valves [by the way all four valves were changed at this time at the suggestion of the dealler ... also rebuilt the top end again with new piston, rings, etc].
On getting my bike back, the dealer noted that the engine is now very noisy [internal noise from the top end of the motor ... not present before latest work] and the resistance against the kick starter is now dramatically increased. It is at this point that I took my Honda dealer the data posted herein regarding CRF valve problems, along with the MXOffroad.com Project CRF-450 article regarding installation of the complete Kibblewhite kit and had them read the information. Next I had them order the appropriate valve spring kit from Kibblewhite and it the engine will be torn down again to replace these components.
What bothers me the most about all this trouble is that I love riding my CRF ... it is the perfect "old man's" bike ... relatively light, hugely powerful to meet any demand and not difficult to ride by those possessing less than professional skills. However, at this point in the story, the modifications done to correct the valve problems have resulted in a dramatic increase in the kick start resistance ... to the point that I cannot kick through with sufficient intensity to start the motor reliably. Up to this point I have easily been sufficiently strong to kick the bike with no problems ... I have over 250 hrs riding time, mostly by myself, and have never had trouble kicking through the start cycle until now.
Of course, my Honda dealer can start the bike with no problem [naturally, he's a big guy pushing 230 lbs or so] and they look at me like I'm getting senile or in need of a Bow Flex ...
Well, if anyone has spent the time to read through this 'horror' story ... I'm looking for some opinions and advice. I put more than 2 K-bucks into this bike when it was new upgrading and altering the componentry to make it a worthy trail bike for Michigan conditions with the thought that I would get several years enjoyment out of it before wearing out the motor or some other important and expensive part. Now this dream doesn't seem to hold much water ...
Considering that similar valve changes and piston/ring changes in the past did not alter the kick start resistance ... why has it changed so dramatically now?
I am not expecting the kick start resistance to change much once the proper Kibblewihite vavle spring kit is installed ... right?
Is it possible the decompression lobe on the cam is not functioning correctly and is causing the loud top end noise as well as the increase in kick start resistance?
Anything else that I might look into regarding the kick start resistance and ways to reduce it back to normal?
Thanks in advance for any help that folks might lend to me on this matter. Please don't think I am complaining about my Honda dealer ... they have sold less than ten CRF-450s since they came out in 2002 and all but mine were to motocrossers who race them and more importantly, do their own engine work ... hence the dealer never sees them except for ordering parts occasionally. I am their best service customer with a CRF-450 and they're cutting me considerable slack with regard to service charges for the work as they really have no experience.
Terry Nestrick
2002 CRF-450R
Scott's triple clamp/Pro-Taper bars/steering stabilizer combo
Scott's Shark Fin
Scott's modified forks/shock/springs for 200 lb rider off road
Works Connection Pro-Perch adj Clutch with Hot Start lever
Arc brake lever assembly
Moose bark buster hand guards
Regina O-ring chain
Renthal 52 tooth rear sproket
BRP billet chain guide
PC Racing Air Filter housing kit
Twin Air Filters & Blue filter oil
ZipTy Fuel Mixture adj screw
BRP spark arrestor muffler cap for stock exhaust
CEET tall form foam with gripper seat cover
Works Connection radiator/shroud braces
Works Connection enduro skid plate