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docmx

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About docmx

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    TT Newbie

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    Florida
  1. It is...
  2. Rebuilding an 03 and having a problem with the cam. It appears to be binding as I turn the crank from the right side TDC access port. The lobes rotate straight back and stop and I can continue turning the crank. It feels like the gears are slipping??? I can reverse direction and the lobes will rotate about 1/4-1/2 around and bind again, while the crank continues to turn. I can't line up the TDC marks on the right side and the cam sprocket as the gears seem to have slipped out of alignment. I would appreciate some ideas on how to fix this. Thanks.
  3. I have an 03 that was making a knocking/ticking noise. I checked the clutch it looked good. Tensioner chain and adjuster were fine, so I took the head and cylinder off. Put a new OEM piston in, reassembled and then found the cam chain would not turn the cam sproket when I rotated the crank. It appeared as though the chain was not aligned with the gear on the lower spindle, so I took the head off and took great effort to make sure the chain was as far over and under the spindle gear as possible. Still same problem. The chain will turn when I have the sproket off the cam, but if I attach it to the cam it will not turn. I'm thinking maybe something is amiss in the lower case. The bike probably has 350-400 hours on it. Any ideas?
  4. I'll check it. Thanks for the suggestion.
  5. I would say it probably has 350 hours on it. I'm hopeful the problem is something simple so that I do not have to crack open the case.
  6. It had new valves, piston and rings about 150 hours ago. We did the screwdriver trick a week ago and most of the noise seemed to be coming from the top right side. I have the cylinder, piston and head off right now and have checked for free play in the rod by inserting finger through small end opening and manually turning the engine over. It rotated smoothly with no evidence of free play. Next on the list will be to remove the left side cover and inspect fly wheel and crank free play. I also thought I might remove the valve that has been tightening and check it to see if it is bent. Any other ideas???
  7. I would appreciate some advice on this. I have searched the forum and found the leading suggestion was a defective chain tensioner; however, the tensioner is working properly.
  8. Several weeks ago this bike became hard to start toward the end of a day of riding. I checked the valve gap and found the right intake was tight at 0. I reset it and the bike started and ran great except there was a slight ticking noise. After 3 or 4 riding trips the ticking noise became more noticeable, so I recheck the gap and found the right intake was slightly tighter than specs. I reset it again only to find the ticking noise became much louder and was noticeable when I rode around the track. I checked the gap again (always at TDC) and this time it was perfect. Anyone have any idea what might be wrong? Background info: I replaced the titanium valves with stainless steel about 3 years ago. I have taken the clutch apart, the right-side cover, and the top end looking for possible problems but to no avail. Next, I am going to remove the left cover to see if there is something loose or amiss around the flywheel. I have checked the crank and the bearings appear to be good...turn easy, no noise.
  9. I ran the spring calculator at Racetech and MXtech and found the proper springs for my 03 CRF450 are .449 and 5.3. My weight is 165 without gear and I am a 50+ C class rider (when I am riding my best). Would I be better off going higher or lower on these numbers since a .45 and 5.3 are not available through these suppliers? Also, does anyone know about Diverse (brand) titanium shock springs? They have a range covering all sizes including odd numbers as listed on Ebay. Would I be better off purchasing the exact spring rate needed? If so, is this a good spring? Would there be a problem mixing a titanium shock spring with Racetech or MXtech fork springs? Thanks for your replies.
  10. I'm estimating I have between 120-150 hrs on my 03 CRF450R and am planning on rebuilding the top end for the first time. I have rebuilt a 2-stroke, but have never done a 4-stroke. I was planning on ordering a Vertex or Wiseco top end kit, but was wondering if I would need to order additional parts. It seems several techs recommend replacing the valves and perhaps the springs. Is that necessary? I would like to order all the parts I need and take care of it in one pass as opposed to piece mealing it, but at the same time I do not want to go overboard, especially since I am just a novice rider. I ride motocross once a week on average. I'm guessing about 1 hr or so per weekend and am a C-class 160 lb rider. Would be interested in alternative parts suggestions and where to get them as well. I will be following the Honda Service Manual in performing the work, but would also like to know if there are good tech articles out there I might want to review first. Thanks for your suggestions.
  11. I want to thank all of you who responded to my request for assistance. I will try cleaning the carb and jets. Will also read about the valves and buy parts for a top end job. Any other suggestions are welcomed.
  12. I bought it in 04. Haven't rebuilt it yet or checked valves, because I was told 4-strokes don't require anywhere near the maintenance of a 2-stroke. I used to rebuild my 2-stroke about every 1 1/2 years. That's for a person who rides on average 3-4 times per month. I figured it was probably about due. Maybe past due--right??
  13. I've owned the bike since it was 3 mos. old and have done routine oil, filter, shock, fork, linkage, tires, chain, sprokets, and slider maintenance, but have never touched the engine, except for changing the spark plug. Everything is set as it came from the factory. No new parts and I have never adjusted the carburator settings. Never had too! It ran perfectly up until now. It still runs strong most everywhere except when hard on the power on rough uphill inclines. My old 97 CR250 did something similar to this, but the stuttering was more frequent. It turned out to be a broken wire to the ignition module. That's why I thought it might be something electrical.
  14. I ride my bike almost every weekend and this past weekend I noticed the engine stuttering under power particularly as I hit the throttle hard going up rough inclines. I changed the plug, drained the gas, added new fuel, and cleaned the air filter, but it is still stuttering as if maybe an electrical problem. I have examined the wiring and see no obvious problem. Any suggestions? This is the first time I have ever had any problems with the engine.