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05-18-2015, 04:00 PM | #1 |
Join Date: Jan 2013
Location: Germany
Posts: 231
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Exhaust gas recirculation
Hi,
I closed the Exhaust gas recirculation coming out of the cylinder and closed the spot where the exhaust gas goes back into the carburettor. Everything fine. Engine started right up... but, there were "clack clack clack" noises as if the valves needed adjustment. So I put everything back the way it was. Started up, engine came on normal. The clack clack noises were gone. Question: why would closing the Exhaust gas recirculation cause the engine to do clack clack noises? I wanted to try this to see if there would be any gain in power. Since the engine was making these noises though, I didn't go for a test ride.
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My CB : http://www.youtube.com/watch?v=ZbZ8q-grmOQ 2012 Skyteam V-Raptor 250 2011 Yamaha Tenere XT 660Z abs 1996 Kawasaki Vulcan 800 Classic 1989 Kawasaki GPZ 500 |
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05-18-2015, 04:41 PM | #2 |
Join Date: Nov 2011
Location: Sofia, Bulgaria
Posts: 436
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I closed mine too, but haven't noticed anything different in the sound. But I also put a straight (a.k.a. loud) exhaust.
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10-29-2016, 04:05 AM | #3 |
so far I haven't noticed unwanted side effects on bike's performance after taking all that stuff away
it simply goes better and faster in terms of average speed and 0 to 100 i just received a Highway Hawk Megaton black exhaust terminal but before I can try fitting it i'll probably need a DB killer and some noise reducting foam............the damn thing is almost EMPTY inside and will sound like a Harley............i like some extra masculine noise but don't want police biting my ass every time I ride around.................. |
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05-19-2015, 12:40 AM | #4 |
Join Date: Mar 2009
Location: Sardis, BC, Canada
Posts: 25,977
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TBR, please show us a pic of the parts you disconnected and then reconnected.
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Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer |
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05-19-2015, 03:45 AM | #5 |
Join Date: Jan 2013
Location: Germany
Posts: 231
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I will post a picture this evening. Krasi, did you notice any gain in power?
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My CB : http://www.youtube.com/watch?v=ZbZ8q-grmOQ 2012 Skyteam V-Raptor 250 2011 Yamaha Tenere XT 660Z abs 1996 Kawasaki Vulcan 800 Classic 1989 Kawasaki GPZ 500 |
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05-19-2015, 04:36 AM | #6 |
Join Date: Jan 2012
Location: ChCh , NZ
Posts: 2,265
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sound like the motor is pinking...
closing off the exhaust in to the inlet there is now more space for air "O2" to be sucked in so now the motor is running leaner... dumb ass idea... you wouldn't run to well if yer had to eat yer own crap so why would a motor... SO....... Are you sure its not a "AIS" (Air Injection System) , which makes a lot more sence that exhaust gases going back into the motor. My Yamaha XT660R has one... it lets air into the exhaust to burn unburnt fuel that enters the pipe... clean air / low exhaust exmissions etc... Dose the motor pop/bang on a trailing/closed throttle out the exhaust pipe as the unburnt fuel in the pipe is burnt.. on the XT closeing it off gives no more power... .
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05-19-2015, 06:46 AM | #7 |
Join Date: Jan 2013
Location: Germany
Posts: 231
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Maybe I didn't seal the intake on the carberrator properly and it was sucking in some extra air... Or maybe I just Need bigger jets then? Krasi, did you Change your jets?
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My CB : http://www.youtube.com/watch?v=ZbZ8q-grmOQ 2012 Skyteam V-Raptor 250 2011 Yamaha Tenere XT 660Z abs 1996 Kawasaki Vulcan 800 Classic 1989 Kawasaki GPZ 500 |
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05-19-2015, 11:35 AM | #8 |
Join Date: Mar 2009
Location: Sardis, BC, Canada
Posts: 25,977
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An air injection system makes much more sense; I think I was short on sleep when I responded last night.
Perhaps the port in the head is just not sealed properly. Do you have a catalytic converter in the exhaust? If so, the air injection is there to benefit the cat.
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Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer |
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05-19-2015, 12:41 PM | #9 |
Join Date: May 2015
Location: Cambridge, England
Posts: 140
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I believe removing parts that you have will kill the cat in the exhaust - you will also have to change the exhaust or cut the existing one open and remove the cat and close it up. I believe I have seen a Highway Hawk silencer fitted which is cat-free. I found it as a youtube video when I watched one of yours, so it is out there somewhere.
This may be a vacuum operated "Air Pump" that puts air in the exhaust after the exhaust valve. It dilutes the exhaust gas mixture and introduces O2. The O2 causes the unburned hydrocarbons in the exhaust to continue burning and reduce pollutants, necessary to meet Euro exhaust restrictions. See this article from Turner University which may be applicable. Exhaust Gas Valve I have seen pictures of similar 250cc engines, some with a little plate oval blocking off a hole in the right hand side of the cylinder and other pictures showing a pipe connected there and disappearing behind the engine into a unit near the starter motor. Is this what you removed? Video of the Highway Hawk silencer . . . Jeff
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05-19-2015, 12:48 PM | #10 |
Join Date: May 2015
Location: Cambridge, England
Posts: 140
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__________________
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05-19-2015, 01:08 PM | #11 |
Join Date: May 2015
Location: Cambridge, England
Posts: 140
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Here is a video of Overlanders modded Raptor - about 3.5 minutes in you will see the exhaust and the oval blanking plate near the exhaust pipe header. It would need rejetting, I would think . . .
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05-19-2015, 01:52 PM | #12 |
Join Date: Nov 2011
Location: Sofia, Bulgaria
Posts: 436
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I didn't rejet, only raised the needle as much as I could. It must be running slightly lean though, as during deceleration it pops from time to time. Which reminds me to take a look at the plug colour just in case.
I think there is a slight power gain, mainly in terms of faster revving. But I could be mistaken due to the higher noise from the open can exhaust. How did you "plug" the port in the cylinder? I was lazy to bother with gasket cutting, so I just applied a fair amount of black sealant on the aluminium plate I made (black is the fastest colour, right?) |
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05-19-2015, 04:36 PM | #13 |
Join Date: May 2015
Location: Cambridge, England
Posts: 140
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Only if you put some go-faster lines in the sealant, at least .5mm deep and 5mm apart and horizontal to the ground. Many make the mistake of putting vertical lines in and it has the opposite effect and you lose any speed benefit.
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- - - - - - - - - - - - - - - - - - - - - - - Riding bikes for over 40 years Honda C50 / SS50 / CB125 / CB250 Velocettes (various) Piaggio's / Honda's / Yamaha's Raptor . . . . the List Goes On . . . . |
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05-21-2015, 06:04 AM | #14 |
Join Date: Jan 2013
Location: Germany
Posts: 231
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Where the two red circles are, is the places I closed. Doing this deactivates that pump or whatever that is in the green circle. This bike has the cat in the pipe where the heat shield is.
(thats not my bike on the Picture. I didn't get to take a pic of mine) I cut a peace of 3mm sheet metal and use the original gasket to Close the Output. The Input nob I closed using a Little rubber cap I found in the garage in a junk box. It was slighly too big, but I used a Little round clamp I put over it. But maybe it still wasn't tight enough and the intake was still pulling air.. Maybe if I put some racing stripes on the front Fender the bike will be faster? The flames on the tank didn't help though.
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My CB : http://www.youtube.com/watch?v=ZbZ8q-grmOQ 2012 Skyteam V-Raptor 250 2011 Yamaha Tenere XT 660Z abs 1996 Kawasaki Vulcan 800 Classic 1989 Kawasaki GPZ 500 |
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05-21-2015, 07:16 AM | #15 | |
Join Date: May 2015
Location: Cambridge, England
Posts: 140
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Quote:
I generally find "go faster" stripes only work if you are under the age of 25. Is the clack-clack sound definately coming from the engine? Using the old fashioned method of holding a short piece of wood against the engine and your ear (short piece of broom handle) can you pin-point more accuratly where the sound is loudest? If you cut 35cm off the end of the house broom, it is fun watching the next user wondering why their arms no longer work with the broom. You just have to keep a straight face . . . . Jeff
__________________
- - - - - - - - - - - - - - - - - - - - - - - Riding bikes for over 40 years Honda C50 / SS50 / CB125 / CB250 Velocettes (various) Piaggio's / Honda's / Yamaha's Raptor . . . . the List Goes On . . . . |
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