I have a 05 CRF250 that my son rides. We have a hours meter on it. Looking for experienced opinions on how many hours we can safely squeeze out of a top end (and valves). I have a 03 CRF450 and have a good idea when top ends are due but the hi rev's of the CRF250 concerns me about hours. Thanks in advance for the advice.
Approximate Hours for Top End
Started by ThumperDadCRF450, Aug 24 2006 09:01 AM
17 replies to this topic
Posted 24 August 2006 - 09:01 AM
I have a 05 CRF250 that my son rides. We have a hours meter on it. Looking for experienced opinions on how many hours we can safely squeeze out of a top end (and valves). I have a 03 CRF450 and have a good idea when top ends are due but the hi rev's of the CRF250 concerns me about hours. Thanks in advance for the advice.
Posted 24 August 2006 - 09:04 AM
i had about 200+ hours on mine before we did anything and the piston still looked fine
Posted 24 August 2006 - 09:30 AM
smf919 said:
i had about 200+ hours on mine before we did anything and the piston still looked fine
Does "top end" include valves? I would think on a moderately ridden engine you could go 200 hrs. Valve would likely go first. At least in my case.
Posted 24 August 2006 - 10:02 AM
my 06 has 85 hours and not a valve has moved and the piston and rings are still a-ok
Posted 24 August 2006 - 10:26 AM
yea top end includes valves. thats the reason i did mine in the first place.
Posted 24 August 2006 - 11:23 AM
This is all valuable info. You guys are great. One question though the hours you are quoting, is metered time or estimate. Thanks again.
Posted 24 August 2006 - 11:32 AM
Personally, if the bikes ridden hard, I wouldn't go more than 50-60 actual hourmeter hours at the most.
When I rebuild mine I recut the seats, install new OEM intake springs, valve seals and leave the valves alone since I have never had a valve problem.
Piston, rings, wrist pin, circlips and gaskets and you're good to go.
When I rebuild mine I recut the seats, install new OEM intake springs, valve seals and leave the valves alone since I have never had a valve problem.
Piston, rings, wrist pin, circlips and gaskets and you're good to go.
Posted 24 August 2006 - 11:51 AM
LOL! I saw this thread earlier and read some of the responses and I was going to say something but I knew Fred would have something to say about this. Nice job TJ, you know your stuff that's for sure! :thumbsup:
Posted 24 August 2006 - 11:53 AM
mine is estimated. i figured that there are about 48 weeks in a year. i ride 2 times a week for about 4 hours. that would be roughly 350 hours on my engine in 1 year correct? :excuseme:
Posted 24 August 2006 - 01:18 PM
Throttlejockey said:
Personally, if the bikes ridden hard, I wouldn't go more than 50-60 actual hourmeter hours at the most.
When I rebuild mine I recut the seats, install new OEM intake springs, valve seals and leave the valves alone since I have never had a valve problem.
Piston, rings, wrist pin, circlips and gaskets and you're good to go.
When I rebuild mine I recut the seats, install new OEM intake springs, valve seals and leave the valves alone since I have never had a valve problem.
Piston, rings, wrist pin, circlips and gaskets and you're good to go.
Fred, you recut the seats and leave the worn(relatively speaking) valves in? That doesn't seem right :confused:
Posted 24 August 2006 - 01:38 PM
If the valves didn't lose any clearance they're not worn.
I've done this on all my bikes. My 02 CRF450 had over 300 hours on it with the original valves. I sold my 04 with around 130 hours on it with the original valves, and my 05 has almost 90 on it.
I've done this on all my bikes. My 02 CRF450 had over 300 hours on it with the original valves. I sold my 04 with around 130 hours on it with the original valves, and my 05 has almost 90 on it.
Posted 24 August 2006 - 01:58 PM
smf919 said:
mine is estimated. i figured that there are about 48 weeks in a year. i ride 2 times a week for about 4 hours. that would be roughly 350 hours on my engine in 1 year correct? :excuseme:
Posted 24 August 2006 - 01:59 PM
Throttlejockey said:
If the valves didn't lose any clearance they're not worn.
I've done this on all my bikes. My 02 CRF450 had over 300 hours on it with the original valves. I sold my 04 with around 130 hours on it with the original valves, and my 05 has almost 90 on it.
I've done this on all my bikes. My 02 CRF450 had over 300 hours on it with the original valves. I sold my 04 with around 130 hours on it with the original valves, and my 05 has almost 90 on it.
Posted 24 August 2006 - 08:27 PM
mikerides33 said:
Is your engine running for 4 hrs each time?
Posted 24 August 2006 - 08:37 PM
watch out SMF, 723onYZ250f might try and start stuff, theres "no way you can get 200 hours out of a stocker"
my bike went on 200, 3/4 compition riding not that me or the kid befor me was pro, it wasnt babied, the only thing wrong was i had bad piston skirt wear
my bike went on 200, 3/4 compition riding not that me or the kid befor me was pro, it wasnt babied, the only thing wrong was i had bad piston skirt wear
Posted 24 August 2006 - 09:40 PM
Dan CRF250 said:
watch out SMF, 723onYZ250f might try and start stuff, theres "no way you can get 200 hours out of a stocker"
my bike went on 200, 3/4 compition riding not that me or the kid befor me was pro, it wasnt babied, the only thing wrong was i had bad piston skirt wear
my bike went on 200, 3/4 compition riding not that me or the kid befor me was pro, it wasnt babied, the only thing wrong was i had bad piston skirt wear
Posted 24 August 2006 - 11:25 PM
TJ just wondering, why do you cut the valve seats if the valves are the same. I get new ones and get them recut so I don't know.
get an hour meter so you can be completely sure of the actual ride time you have on it.
ThumperDadCRF450 said:
I have a 05 CRF250 that my son rides. We have a hours meter on it. Looking for experienced opinions on how many hours we can safely squeeze out of a top end (and valves). I have a 03 CRF450 and have a good idea when top ends are due but the hi rev's of the CRF250 concerns me about hours. Thanks in advance for the advice.
Posted 25 August 2006 - 03:52 AM
723onYZ250f said:
TJ just wondering, why do you cut the valve seats if the valves are the same. I get new ones and get them recut so I don't know.
get an hour meter so you can be completely sure of the actual ride time you have on it.
get an hour meter so you can be completely sure of the actual ride time you have on it.
Because the seats still get deformed, so the seating surface isn't to spec.
