Low compression on 03 Rincon - Honda Foreman Forums : Rubicon, Rincon, Rancher and Recon Forum
 
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post #1 of 5 (permalink) Old 12-07-2009, 10:36 PM Thread Starter
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I had a friend drop off his 03 Rincon for me to check out after someone told him his cam was bad. This unit has always had what sounded like valve clatter, but usually it quieted down after a minute or so. I also suspect that the owner put some cheap oil in it to get him by a couple months ago. I personally haven't heard of cam lobes wearing out before, but I'm not super familiar with the Rincon engine. I've always worked on dirt bikes and was wondering if the Rincon engine has any sort of internal compression release as the CRF450 does. I didn't see one, but I wasn't for sure. The reason is I pulled a compression test on this unit with two different gauges and they both show 65-70 psi. I know on normal four-strokes it's around 140 or so. I checked the valve lash (.006 In, .013 Ex), which was spot-on, then removed the rocker cover and visually inspected the push rods and guide buckets and cam lobes. Everything looked good and I didn't want to tear into any futher until I was sure that I had a low compression situation.
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post #2 of 5 (permalink) Old 12-08-2009, 08:42 PM
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The cylinder compression @ 390rpm should be 74 PSI.

Now what is the problem you are trying to solve exactly? This rattle you hear, do you think it could be the cam chain? The tensioner going out on the 03-05 Rincon's was a very common issue. It would cause a rattle like tapping noise usually when first started, but would then go away.

PS I have heard of the cam lobes wearing out on the early Rincon's, but I don't think this is your issue.

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post #3 of 5 (permalink) Old 12-08-2009, 09:13 PM
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mac has it answered, there is an automatic decompression on the camshaft and that's why the lower number.




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post #4 of 5 (permalink) Old 12-08-2009, 11:27 PM Thread Starter
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Ok, that explains a lot. Before I got it, you would start the machine up and it would sound as if the valve were way out of adjustment. Usually after a few minutes, it would quiet down. Over the past few months, though, the power has diminished tremendously and now it will hardly run at all. I don't want to throw some parts at it, but I don't visually see anything wrong so far.
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post #5 of 5 (permalink) Old 12-09-2009, 07:27 AM
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QUOTE (mxracer28 @ Dec 9 2009, 12:27 AM)
Quote:
Ok, that explains a lot. Before I got it, you would start the machine up and it would sound as if the valve were way out of adjustment. Usually after a few minutes, it would quiet down. Over the past few months, though, the power has diminished tremendously and now it will hardly run at all. I don't want to throw some parts at it, but I don't visually see anything wrong so far.
Can you record a video of it making the sound? The tensioner isn't a hard or expensive fix.

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