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No Compression AGAIN!!

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So I was having some problems with my bikes compression. Bought the bike, the valves were off a bit. I just decided to throw ss valves in it to play it safe. Threw in the valves and went out. Bike was not kicking over easy at all when hot. I decided to ride a full day. At the end of the day I went out for one last lap, pinned it in second shifted to third and bike bogged out. Bike wont start at all even when bumped now and there is no compression. Im pretty sure the valves were put in right, and I took my time with the cam chain. What could have happened any ideas?

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How long is a string?

It could be many many things...time to tear it down!

Did you "set" the cam chain tensioner or just put it on?

How many rides on the piston?

What about the crank?

Is there water still in it?

What's the oil look like? Engine and gear side.

What's the oil filter look like?

Do a compression or leak down test yet?

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Pull your oil filter and look for brass colored shavings. If there in there your crank is toast.
:lol:

Did one a few weeks ago for someone,,,They ran it until it jammed a hole in the case:banghead::)

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check the valve seats to see if they are sealing. you can put some sort of soulution or water in the bottom of the head with the head off and see if any water leaks through. or take a high powered led flash light in a dark room and put them at the bottom of the head and see if there is any light coming through. but my guess is that you have a bad ring, or a bad cylinder

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and also check the oil filter like it was stated above. and does the kickstarter turn over freely? with no weird noises or feels?

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If it happened that quickly, my money is on the cam timing has jumped, either from the tensioner installed incorrectly or the chain being stretched badly.

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OK tore it apart. Turns out I sucked a valve. The timing was perfect, I guess the guy before me shaved the head or piston to get some more power, and did it to much. On high rpm the piston was hitting the valves. So have to get another valve and whatever else this idiot did while in there. My mechanic is in the process of measuring everything with a micrometer. The hard part about it is that I cant find any measurments on the head to get a stock reading. Im going to replace the piston reguardless because it was about done.

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OR the timing chain could have snapped...when mine snapped i had no compression and i didnt know it broke tell i took the motor apart...i thought my rings were shot..it was much worse then rings.

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If the piston was hitting the valve at high rpms, it may have been weak/sacked valve springs. They should be replaced pretty often. IIRC, they are about $7 each from Honda. When they get weak, you'll see evidence of the valves knocking the carbon off the piston. Things progress downhill from there. The 150R is pretty bad about this, even after the recall springs were installed.

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UPDATE

Looked at it again with my mechanic in more detail. He now thinks that the cam slipped on the gear. He said its really rare and really hard to find but its that. So $350 in parts and we will se what happends.

To the responses

The cam chain was perfect and not broken.

When replacing intake with Stainless steal valves I did not put in HD springs because I know a lot of guys that race with out and are fine. The intake side is still in spec since install so i think the springs are fine

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I have seen/been-bit-by the 150R cams rotating on the gear holder throwing the timing off almost two teeth. When something catastrophic inside happens (valve dropping, etc), that's when it'll happen.

If you installed the heaver SS valves without switching springs, unless you have a 12 year old girl riding it in a non-aggressive manner, I'd be fairly certain you're gambling in territory you don't want to be in, even for just an instant (such as a missed shift). I ran the Kibblewhite's in my 450 with new stock springs for a while. Had a fast buddy of mine ride it and it swallowed a valve- his words were "I couldn't believe how high it would rev, how long it would pull each gear.... and then everything went silent".

Just because other guys do it, doesn't mean its fine- it means they haven't been snake bit yet. I had a guy with rode his 150R in mini-supermoto. We pulled it down to do a routine top end and you could see where the valves had been hitting the piston for so long, it had made new depressions in the piston dome cutouts.

The 150R motors run very well but are very high maintenance motors.

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I'm willing to bet it was off timing.

x2. I would bet that timing was one tooth off. It looks fine, bike will start first kick (albeit hard to kick), but harder when hot. Just like you described! One full day of riding, and .... Just my 2 cents

Bike was not kicking over easy at all when hot. I decided to ride a full day. At the end of the day I went out for one last lap, pinned it in second shifted to third and bike bogged out.

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The timing was not off. I checked the timing and it was spot on. I made sure the second time around to get it perfect. When I pulled the bike apart it was good.

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Font run those springs and those valves. Either run the right springs or the ti valves.

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