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Discussion Starter #1
Hey all

For a while now I've been getting pretty sick of how noisy the top end of my motor is, so today I decided to take off the camshaft cover and inspect the decompression cams. But what I ended up doing was removing them altogether.

I'm in Australia, and while it can get cold, our winters are pretty mild, so I don't feel cold starts will be an issue.

So my question is, does anyone see an issue with this?

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If your engine starts and runs without them you may well be saving yourself from a future headache. I confess to not having a close knowledge of how they operate - I’m not a mechanic - but I do know of 2 1700s that needed new exhaust cams because one end where the decompressor attached had broken. My understanding was that the decompressor assemblies put an extreme amount of pressure on the camshaft and in these, presumably isolated cases, it sheered off. Both were fixed under warranty by the way; one as goodwill because the bike (Storm) was about 5 years old.
 

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Its my understanding that the decompression cams fuction is to save wear & tear on the starter. I would like to hear how it works out for you. While l was doing my 12000 mi. valve check, l noticed that the decompression system looks weak to me. Ive heard that there is a spring upgrade that l had planned on doing. If its feasible to remove it without ill effects, l would do it. One less thing to break, right? Im interested in hearing others feedback on this subject
 

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There is a set of you tube vids....6 sessions I recall on doing a valve check on a 1600.....excellent info. In there one can see the function of the decomp cam. If indeed there is a different spring being used I'm unaware of it.....but certainly worth looking into. These decompression mechanisms aren't new technology and are used in automotive down to simple lawn mower engines. Why ours is sloppy and apparently adds to top end noise remains a mystery.
 

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At some point in time they supposedly fixed the breakage issue. Not sure what year but i do recall being told the cams that went in mine with the BB kit in ate 2010 had the new revised decomp parts. I don't know what they did to them exactly but you now know everything i was told and read.
 

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Discussion Starter #6
Thanks for everyone's posts!

I've removed the decompression cams and am slowly putting the bike together. I'm a little concerned that the starter might have issues turning the engine over because I had to turn the camshaft to get to everything and I had to end up removing a couple spark plugs because I just couldn't turn the motor over. Anyways, I'll let you all know how it goes once I'm finished!

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Homer, please share any news you have. I've often suspected this to be part of the clacker noise. I recall on the 1600 forum someone did this a few years ago and claimed it solved his knocking noise with no starting issues. However I can't find that thread where it was discussed
 

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Homer
Equally anxious to learn of the outcome.....recall you've put up with noise for some time. How did you make out with the brakes?
 

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Discussion Starter #10
UPDATE!

After having to deal with a stubborn radiator hose that kept leaking on me and a 5 year old battery that won't keep enough power in it, ice just come back from a short ride and I'm pleased that I did the mod.

The motor is still noisy, but it's not the top end. It definitely idles smoother. I used to have an awful noise when I'd rev the motor then back off to change into the next gear, and that seems to be gone. And the best thing is that there is no way now that they will explode and then have little pieces run through the motor!

I just need to now get a new battery, and I'm planning on getting the biggest one that I can fit. 5 years out of a battery is pretty good I reckon! Still disappointed that the motor is so noisy, especially for a bike that's only done 9000kms, but looks like I'll have to live with that like most here do.

The brakes are getting redone by the smash repairer as soon as I get it to him. They are still ****, which is most likely due to them replacing the rotors but not the pads.

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Homer, if I'm reading you correctly this didn't really solve the noise. You mentioned the top end seems quieter but not the bottom end?
With that I assume you still have the knock/ clacking that is most prevalent in the 2500-3500 rpm range?
 

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Discussion Starter #12
You're pretty much correct.... It was never going to solve any issues coming from the bottom end, but the top end is quieter. The new battery is arriving in a couple days and then I'll be able to take it for a proper ride which will give me a better opportunity to check the results, which I'll share.

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Im interested in hearing how the starter wings it over with a strong battery. I have the 24000 mi. valve check coming up. Maybe lll remove mine. The valve noise doesnt bother me. Im used to old school British bikes so the 2012 sounds quiet to me. Its more the thought of things coming apart down the road.Even though, it doesnt sound like total failure of the system happens that often.
 

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Discussion Starter #14
I'm with you, Farmer! I came give you any feedback regarding a new battery because it still hasn't arrived, but I'll let you and everyone else know soon.

The engine is still loud, but not as loud as before. Most of the sound is coming from the bottom end, which could be piston slap, and from what I've heard this has never caused an issue.

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Hello everybody,

I think my bike is experiencing the same issue posted here, but since I am no mechanic or expert, I wanted to share my video of the clicking noises I am getting. Is this the same sound you are experiencing?
The sounds -at times- are associated with a drops in RPM. At cold starts, they sometimes turn the engine off.

This clip shows the clicking sound:
https://vimeo.com/319034274

This is another clip of clicking sound when I rev up the engine and then goes back to idle:
https://vimeo.com/319034200

Excuse my ignorance, but how bad is it if it turns out that the decompression cam mechanism is broken?
Can I still ride the bike?
Does anyone know the approximate cost of the fix (just to have an idea)?

Thanks in advance
 

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Discussion Starter #17
Whatever it is it certainly isn’t right. I wouldn’t be riding it until I’d had it checked out.
I agree, I wouldn't even start the bike again!

To me that sounds like it could be the decompression cam with broken springs, or maybe worse, but it sounds like the sound that I made after I removed them and tapped them together.

The low thump sound is something I occasionally hear which I believe to be the piston slap.

UPDATE ON MY BIKE:

The new battery works well, but it will still sometimes turn the motor over a little and then stop, but then it will proceed to turn it again and start. It's kind of like the battery is a little flat, but of course it isn't, so it must be the high compression. In any case, it always ends up starting. My motor is now heaps quieter than it was before, which I'm extremely pleased about. I was cruising at 90 KMs/hour the other day and couldn't even hear the motor for a change!!

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