I am mechanically inclined, but working outside of my realm. My nephew has 2011 Honda CRF150R dirt bike. He decided to do his own own change. He seemingly drained the engine oil, then filled the transmission oil. He proceeded to ride, it quickly locked up.it would not kick over, then eventually did, bit no fire.
I have taken it apart, expecting the worst. Right away I found a broken piece of cast, sitting atop the head, below the camshaft. I found the casting in the cam holder was broken. I took the head off and it looks ok, no cobtact or issues. The cylinder wall still had slight oil, and piston looks ok. I did not remove the cylinder as I do not see a need to as of yet.
The camshaft looks as it got hot, but lobes look OK in my opinion. Should I just change the cam holder? I have attached a video I found where the gentleman had the same concern, and exact same piece missing/broken. He changed the cam and mentioned it is not at the correct location when set at top dead center. This makes no sense to me as the cam is directly bolted to the gear.
Similar video: https://youtu.be/Qn4k4yuSk9I
Your opinion and help appreciated. Trying to fix on the cheap
I replied in your other thread. The cam sprocket bolts to the 2-bolt flange piece and that piece is pressed on the cam. In the video, his has slipped on the cam causing the bike to jump time. That's why his valves contacted his piston and the motor would not turn over. This may have happened in yours also. There may have been piston-valve contact that caused the lock up. In any case I'd be taking the head off to inspect the valves and piston and make sure the cam timing has not slipped. I would also not reuse that cam. Those lobes look rough. I'd also pull the motor side covers off, especially the left side and inspect in there for any pieces that fell down. Check the rotor magnets and stator coils closely for any loose chunks. Also remove and clean the filter screen if it is accessible in there.
Thank you. Didn't know was pressed in. Figured all one piece, that is what made no sense to me, I was like the marks all line up, how cpuld it be off, not like it could be twisted. I'd love to buy a cam and holder all together then. Piston and head seem ok! Other than some carbon on the valves. I have not popped rhe valves out yet to make sure stems are not bent etc. Little bugger better fill the oil next time.
This should help you with the cam hub location. If the valves didn't hit the piston, the cam should be okay.
Much appreciated. This one looks similar and fine. I think it was just the lack of oil broke the cam holder. Took it all apart and everything else looks fine luckily
The Shop
It actually looks like yours may have spun slightly. Does the decompression weight hit the cam gear bolt (or come very close to it)?
Thanks for all the help. Parts finally arrived and installed. Went to fire, was quite hard to kick over. Immediately figured issue with hoe I installed decompression. Had a peak. It wasn't moving. Backed off keeper bolt, then moved freely. But if I Tighten at all, it won't. Any tips or correct installation instructions? How much do you wind up the spring? Thanks in advance
Did you ever figure out the decompression lever? Mine dangles and won't hold up its own weight when upside down. Did you have to "wind' the spring?
Did anyone ever figure out why the decompression lever is too tight when the bolt is torqued properly? Seems like a washer is missing in these setups but none indicated in schematics.
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