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Message: [QUOTE="Rich Rohrich, post: 1103718, member: 16241"] [b]Service Intervals for the CRF150R direct from Honda[/b] These are the service intervals Honda is recommending for the new CRF150R engine. [b]Valve clearance check[/b] - After the break in ride and every 6 races or 15 hours after that. No specific interval on valve or valve spring replacement. We'll be tracking that out here. It should be interesting to see how well the steel valves hold up. I'll be using a high end Rimac spring tester to watch the rate at which the valve springs lose their pressure. This gives a good indication of the spring quality and relative severity of the cam dynamics. [b]Piston, rings, piston pin[/b] - Replace every 6 races or 15 hours. It's a single compression ring slipper skirt piston similar to the CRF250F. It's running clearance (piston to wall) is tight at 0.0006"- 0.0015" , and the upper limit on clearance is 0.003". This is a REAL race engine, it's not a trail bike so "cheating" on the piston maintenance won't be easy. The cylinder head is built like the CRF450 and uses a separate cartridge type carrier for the cam, and a bolt on cam sprocket. That's great from a maintenance and cost standpoint if a head ever has to be replaced. It also makes shimming the valves much simpler. The bolt on cam sprocket opens up a whole range of cheap tuning opportunities. :cool: It uses standard bucket lifters on the intake, and a pair of offset roller rockers for the exhaust. The engine holds a fairly generous amount of oil considering the size of the engine. It uses the now standard CRF split between engine and trans holding 0.70 liter on the engine side and 0.65 on the transmission side. Good move on Honda's part. Cam timing seems fairly mild considering the power peak (reportedly 12,500), but I haven't measured the valve acceleration rates yet so these numbers could be a bit deceiving. IVO 15 BTDC @ 1mm lift IVC 48 ABDC @ 1mm lift EVO 50 BBDC @ 1mm lift EVC 25 ATDC @ 1mm lift With the help of Service Honda I'll be tearing an engine apart to take a much closer look at the cam dynamics, the flow potential of the cylinder head and a few other tuning areas. I'll be going through an entire engine and essentially blueprinting it and documenting the initial maintenance quirks and anything else that looks interesting. We'll have lots of nice clear pictures and tons of details, so stay tuned. [/QUOTE]

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