Decompressor damage

andyvh1959 · 12-22-2020, 02:22 PM

Damage meaning inside the engine when the decompression system fails. Anyone else, like MAS, taken the decomp system out of their engine with any negative results? I did a search on the forum for "decomp" but nothing came up. I'm tearing into the engine on my 03 Classic this winter, so I'll be removing the decompression system as a safe guard against future damage.

Also, I've read that not all 1600's have the decompression system for starting? When I searched "decomp" I did find a post from the forum member that said the 2003 Classic 1600 does not have the decompression system. My Classic is a 2003 model. I also need to clarify that this winter I'll install complete 1500 Mean Streak heads and cams on my Classic. Not sure if the 1500 Mean Streak does or does not have the decompressor system.

duffy · 12-22-2020, 03:07 PM

I had an 05' 1500 Classic and it "did" have the de-comp feature. Mine never had a problem. Since the 1600 was basically the same engine I would think that it had one also.

DragonLady58 · 12-22-2020, 03:18 PM

Disabling the decompressor is easy....no lasting ill effects. It was mostly used to help the big 1500s spin over easier on hot days with crappy fuel....when new when the compression is just like new allows for faster easier starts....
Haven't been running any on mine for the past 10 years....

andyvh1959 · 12-22-2020, 05:35 PM

That's what I needed to hear. The decomp is coming off my bike. Thanks.

Gus0458 · 12-22-2020, 08:22 PM

I have a 2001 1500fi nomad. Please explain to me the decompression system.
TIA
Mark

andyvh1959 · 12-22-2020, 11:16 PM

It is a system to lower the cylinder pressure during starting (only) to make the engine crank over easier until it fires up. The system acts on the end of a camshaft to hold an exhaust valve so slightly open during cranking/starting. Once running the device returns the camshaft to normal timing. But, over time, these decompression components can fail and the bits falling down inside the engine can create a lot of damage.

**Kawi_addict** · 12-23-2020, 12:34 AM

I lost an engine once to a decomp cam spring that fell off. The slider fell over and rattled around inside the valve cover for a few months I would hear something awful maybe once a week then not again for a few weeks..... Then one day it rolled up against the cam and hit then BOOM

mick56 · 12-23-2020, 08:22 AM

I found one of the springs in the sludge trap, when i changed the oil. I asked on here, and showed a photo, but nobody knew what it was. Many miles later, when i fitted new cam chains, i discovered it was off one of the de compressors. I could see, where it had been working it's way into the cylinder head. So i took them both off. Never noticed any difference at all.

andyvh1959 · 12-23-2020, 08:21 PM

So the consensus is; disable the decomp now or suffer the inevitable results. May just make some noise up top, may fail your entire top end. My Classic has 34,000 miles and I am taking the decomp off this winter.

Seems its more of a detriment than it is any gain.

**Kawi_addict** · 12-24-2020, 10:06 AM

Yep exactly. Get rid of it if you're in there already. Idk my 1600 has em or not but if it does. The system is staying put until something breaks. I'll take it off when she breaks but that'll be around 200,000,000 miles from now bc you know kawi POWER!!!! LOL

mick56 · 12-24-2020, 10:53 AM

You might not know that the spring has come off. I never heard any sounds that caused concern. But as Kawi addict said, his engine was fucked by it. A bit like the POG on the early bikes. Roll the dice i guess. Merry Christmas anyway.

12-22-2020, 02:22 PM	#1
andyvh1959 Advanced Member Join Date: Dec 2017 Location: Green Bay WI Posts: 760	Decompressor damage Damage meaning inside the engine when the decompression system fails. Anyone else, like MAS, taken the decomp system out of their engine with any negative results? I did a search on the forum for "decomp" but nothing came up. I'm tearing into the engine on my 03 Classic this winter, so I'll be removing the decompression system as a safe guard against future damage. Also, I've read that not all 1600's have the decompression system for starting? When I searched "decomp" I did find a post from the forum member that said the 2003 Classic 1600 does not have the decompression system. My Classic is a 2003 model. I also need to clarify that this winter I'll install complete 1500 Mean Streak heads and cams on my Classic. Not sure if the 1500 Mean Streak does or does not have the decompressor system. __________________ My $1200 Vulcan, to start from. Login or Register to Remove Ads Last edited by andyvh1959; 12-22-2020 at 02:25 PM.
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12-22-2020, 03:18 PM	#3
DragonLady58 Sr. Member Join Date: Jul 2016 Location: Somewhere South of Alaska.... Posts: 2,351	Disabling the decompressor is easy....no lasting ill effects. It was mostly used to help the big 1500s spin over easier on hot days with crappy fuel....when new when the compression is just like new allows for faster easier starts.... Haven't been running any on mine for the past 10 years.... __________________ --------------------- Don't start no schit, there won't be no schit.... My Sarcasm is directly proportional to the amount of Stupidity involved --------------------- VBA#03239 VROC#37400 VRA --------------------- 2014 Vaquero 2001 Nomad FI 2003 Street Glide (sold) 1500 Meanie, fresh rebuild (sold) 90s BUBF Bobber (sold) 2001 UltraCycle FatPounder (Sold) 1975 HD ElectraGlide (Sold) 1982 Kawasaki Z1 Chopper (Sold) Suck It Up & Ride!
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12-22-2020, 05:35 PM	#4
andyvh1959 Advanced Member Join Date: Dec 2017 Location: Green Bay WI Posts: 760	That's what I needed to hear. The decomp is coming off my bike. Thanks. __________________ My $1200 Vulcan, to start from.
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12-22-2020, 08:22 PM	#5
Gus0458 Jr. Member Join Date: Aug 2018 Location: Mio, Mi/Jacksonville, Fl Posts: 7	I have a 2001 1500fi nomad. Please explain to me the decompression system. TIA Mark Login or Register to Remove Ads
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12-22-2020, 11:16 PM	#6
andyvh1959 Advanced Member Join Date: Dec 2017 Location: Green Bay WI Posts: 760	It is a system to lower the cylinder pressure during starting (only) to make the engine crank over easier until it fires up. The system acts on the end of a camshaft to hold an exhaust valve so slightly open during cranking/starting. Once running the device returns the camshaft to normal timing. But, over time, these decompression components can fail and the bits falling down inside the engine can create a lot of damage. __________________ My $1200 Vulcan, to start from.
	0

12-22-2020, 03:07 PM	#2
duffy Sr. Member Join Date: Apr 2009 Location: Hot Springs, SD and other warm and dry places Posts: 1,043	I had an 05' 1500 Classic and it "did" have the de-comp feature. Mine never had a problem. Since the 1600 was basically the same engine I would think that it had one also.
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12-23-2020, 12:34 AM	#7
Kawi_addict Join Date: Mar 2019 Location: K.c. Missouri Posts: 128	I lost an engine once to a decomp cam spring that fell off. The slider fell over and rattled around inside the valve cover for a few months I would hear something awful maybe once a week then not again for a few weeks..... Then one day it rolled up against the cam and hit then BOOM __________________ Love team green owned almost all of them from atvs to baggers and even a lawn mower My dog is my co pilot
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12-23-2020, 08:22 AM	#8
mick56 Sr. Member Join Date: Nov 2013 Location: The Newforest, England Posts: 4,664	I found one of the springs in the sludge trap, when i changed the oil. I asked on here, and showed a photo, but nobody knew what it was. Many miles later, when i fitted new cam chains, i discovered it was off one of the de compressors. I could see, where it had been working it's way into the cylinder head. So i took them both off. Never noticed any difference at all. __________________ when this you see, remember me, and bear me in your mind, let all the world say what they may, speak of me as you find.
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12-23-2020, 08:21 PM	#9
andyvh1959 Advanced Member Join Date: Dec 2017 Location: Green Bay WI Posts: 760	So the consensus is; disable the decomp now or suffer the inevitable results. May just make some noise up top, may fail your entire top end. My Classic has 34,000 miles and I am taking the decomp off this winter. Seems its more of a detriment than it is any gain. __________________ My $1200 Vulcan, to start from.
	0

12-24-2020, 10:06 AM	#10
Kawi_addict Join Date: Mar 2019 Location: K.c. Missouri Posts: 128	Yep exactly. Get rid of it if you're in there already. Idk my 1600 has em or not but if it does. The system is staying put until something breaks. I'll take it off when she breaks but that'll be around 200,000,000 miles from now bc you know kawi POWER!!!! LOL __________________ Love team green owned almost all of them from atvs to baggers and even a lawn mower My dog is my co pilot
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12-24-2020, 10:53 AM	#11
mick56 Sr. Member Join Date: Nov 2013 Location: The Newforest, England Posts: 4,664	You might not know that the spring has come off. I never heard any sounds that caused concern. But as Kawi addict said, his engine was fucked by it. A bit like the POG on the early bikes. Roll the dice i guess. Merry Christmas anyway. __________________ when this you see, remember me, and bear me in your mind, let all the world say what they may, speak of me as you find.
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