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SuzukiSavage.com
/cgi-bin/YaBB.pl General Category >> Rubber Side Down! >> After glow? /cgi-bin/YaBB.pl?num=1552607217 Message started by Zook on 03/14/19 at 16:46:41 |
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Title: After glow? Post by Zook on 03/14/19 at 16:46:41 Is this normal? |
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Title: Re: After glow? Post by Matchless G11 on 03/14/19 at 16:51:59 Well if that is a Harley muffler that has a catalyst in it, it might be normal. but the short answer is no. But it looks cool! ;) |
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Title: Re: After glow? Post by Zook on 03/14/19 at 17:43:28 It is a Harley Dyna muffler and The pipe is wrapped |
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Title: Re: After glow? Post by Ruttly on 03/14/19 at 20:15:47 Your carb is most likely LEAN. |
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Title: Re: After glow? Post by SpamyToo on 03/15/19 at 03:34:14 That wrap really holds the heat also. I melted a pipe with a similar combo you have there. https://photos.app.goo.gl/mEL4VbVr7BQtZmhc6 |
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Title: Re: After glow? Post by Dave on 03/15/19 at 04:00:14 On the group rides.....I have seen the inside of the Harley mufflers emitting a red glow. The higher the cruise speed....the brighter the glow. I am sure fuel mixture has some affect, and with or without catalyst likely has an affect as well. The Harley muffler has an inner pipe with holes and a plate blocking the middle...the exhaust flows out of the inner pipe into the outer chamber, then back through holes and into the inner pipe and out the back. The outer chrome housing has insulation inside that absorbs sound...and also keeps the inner pipe from dissipating much heat outward - so the inner pipe gets really hot. After a bunch of miles....the inner pipes get tired and they break and come loose - and the muffler needs to be replaced. Most of the members on this site will never ride their bikes long enough to wear a muffler out....some of the long term members like Serowbot and MMRanch have worn mufflers out. |
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Title: Re: After glow? Post by Matchless G11 on 03/15/19 at 04:04:33 17212425400 wrote:
Not a fan of wrap, It holds in heat, probably not good for air cooled engines. One of the paths for heat loss is the pipe, The hottest part of the bike is the exhaust valve, heat reflecting back will just keep it hotter. There might be some slight benefit in racing but racing is not about stop and go traffic and long life of a motor. And besides some wraps absorb moisture. Example, take some semi dry towels balled up out of a dryer and place them on a table leave them for hours. Later they will be still hot and wet in side the ball. Thus same effect with pipe wrap. Rotted out pipes. |
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Title: Re: After glow? Post by Zook on 03/15/19 at 13:59:11 I like the look of the wrap and this is not a long ride bike. I have a Vstrom for that. It’s not a ride in the rain bike either for that matter so I am not too worried a the wrap getting wet. |
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Title: Re: After glow? Post by youzguyz on 03/15/19 at 14:22:36 I've worn out a LOT of Harley mufflers. Thankfully, I usually get them free my my Harley riding buddies that just HAVE to change out the stock exhaust. Still got 3 spares... |
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Title: Re: After glow? Post by Ed L. on 03/17/19 at 11:13:26 Drill a 1/2 inch hole in the baffle, the pipe will run cooler, sound much better and the bike will love it. |
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Title: Re: After glow? Post by Zook on 03/29/19 at 13:34:34 I drilled the bafel with a 1/2 inch bit and an extension. I went for a 15 minute ride. It still glows bright red inside. It’s a little louder now. In fact that is about as loud as I would want it. Doesn’t seem to have made much difference. |
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Title: Re: After glow? Post by batman on 03/29/19 at 16:33:09 I tried drilling a half inch hole in one of my Dyna mufflers and lost the baffle completely in a few thousand miles, had to swap back to a stock dyna , I'm not tempted to try a hole again . |
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Title: Re: After glow? Post by batman on 03/30/19 at 11:22:58 Their is another thing to consider when using the stock header, it's already "wrapped ", that is to say the header is double walled , helping to retain exhaust gas temperature. Placing a cloth wrap over this may be driving temps over the top, and part of the reason your seeing the glow. Where it may prove a benefit to wrap larger custom headers (single layer headers with larger surface areas that cool the gases faster) I would avoid their use on a stock header. |
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Title: Re: After glow? Post by Zook on 03/30/19 at 14:33:55 Well I have another muffler, had to buy 2. So I guess if or when it goes I will slap on another one. Might as well see how long it lasts. |
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Title: Re: After glow? Post by batman on 03/30/19 at 20:20:47 Well HD Dyna mufflers (used) are reasonably priced, I would be more concerned about the what the wrap is doing to your header. The fact that you can't see it, negates the chance of telling you if it's bluing , which usually means the carb is running lean ,(or very rich) or if it's rusting. Running rich will carbon the motor ,foul your sparkplug ,and could lead to detonation,and wastes fuel , lean will make the motor run hot and could lead to burnt valves ,or cause other damage. |
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Title: Re: After glow? Post by DragBikeMike on 03/31/19 at 11:58:20 I have trouble getting a handle on this "lean runs hot" concept. Back in the day, when British twins were all the rage, blue pipes were commonplace. There was even a product, Blueaway, intended to address this common problem. The go-to explanation for the cause of the dreaded blues was "your mixture is too lean". I accepted that as gospel. I'm a little older now and tend to look into things a bit more. When I attended Airframe & Powerplant school, we were taught that exhaust gas temperature (EGT) was highest at the ideal stoichiometric air/fuel ratio, about 14:1. That lesson was reinforced when I was in the air force. I was a reciprocating engine mechanic. Our training manuals discussed adjusting fuel mixture using EGT and explained how EGT is highest at the ideal air/fuel ratio. But I also have real world experience with blued pipes, and a stuck valve or two, that seemed to be the result of lean mixtures. Every time I see a comment on this forum suggesting that someone's air/fuel ratio is lean because the header pipe is blue, I find myself digging around on the internet in search of an answer to this mystery. I pretty much always come up with the same answer. The EGT is hottest at stoichiometric, and gets cooler the further you move away from stoichiometric in either direction (lean or rich). So I figured I would share the best example I found. It's clear and easy to understand, and has a nice graph included. I'm not sayin that the blues aren't the result of a lean, or a rich, mixture. I'm sayin I don't fully understand the phenomenon. I figured I would share the info and see what shakes out of the bushes. This is a quote directly from the Aviation Stack Exchange: "Exhaust Gas Temperature (EGT) provides pilots a way of monitoring the fuel/air mixture in the engine. It uses the stoichiometric mixture (where Fuel and Air are perfectly balanced so that there is no unburned fuel and no unburned oxygen at the end of the combustion event) as a reference: At this mixture the EGT is at its hottest ("Peak EGT"). Making the mixture richer or leaner will reduce the EGT, and all other mixture settings are described in terms of "Degrees Rich of Peak" or "Degrees Lean of Peak"." This is a link to their site: https://aviation.stackexchange.com/questions/21466/what-appears-on-egt-gauge-if-the-mixture-is-rich-or-lean Sorry about the link not being active. If you want to go to the site, you have to copy and paste into your browser. I'm old and don't have the IT skills that you whippersnappers have. Finally, I have included a nice graph from Lycomming (aircraft engine manufacturer) that clearly shows the relationship between AFR and EGT. If you fish around on the web you can also find similar graphs from other manufacturers, like Continental, etc. I'm curious about your experience with AFR as it relates to your exhaust pipe, cylinder head temp (CHT), stuck exhaust valves, etc. Regarding the afterglow, I'm with MatchlessG11, my bet would be a catalyst. If that Dyna muffler has a catalyst the AFR achieved with a carburetor is most likely way too rich for the catalyst. Rich mixtures cause catalysts to run off-scale hot. Just a guess. I know I wouldn't want that goin on in my muffler. Get it fixed. |
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Title: Re: After glow? Post by justin_o_guy2 on 03/31/19 at 12:54:27 My new Guzzi made almost twenty minutes of Houston traffic before the pipes were blue in the radius leaving the heads. Makes sense that the E.G.T. would be highest at the exact mix of air and fuel that uses both up. The anomalies complicate things.. daggum reality, anyway. |
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Title: Re: After glow? Post by Dave on 04/01/19 at 03:58:23 I believe the biggest cause of blue pipes....is folks that are stopped in traffic and idling for extended periods - or even worse yet the folks that warm up their bike before they ride.....or start the bike up in the winter and run it to keep the battery charged and the fuel in the carb fresh. With no air moving on the outside of the pipes to cool them - the pipe gets hot enough for the bluing to occur in a very short period of time.....especially if you hold the throttle open a bit to help the engine warm up quickly. It could be that because lean mixtures burn exhaust valves and spark plug electrodes and can put holes in pistons - that folks believe the engine is running hotter. What really occurs is the oxygen left over after combustion still has the ability to help things "burn" - and the exhaust valves and spark plugs are the hottest parts of the engine and burn first (and the overly hot spark plug electrode can burn a hole in the piston). On two stroke bikes the lean mixture can starve the engine for lubricating oil and the piston/cylinder usually seizes. I start my bike and run it for about 30 seconds....then ride off slowly and avoid full throttle until the engine warms up, and I very seldom have to ride in traffic...........7 years and no bluing on my header. |
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Title: Re: After glow? Post by DragBikeMike on 04/01/19 at 13:21:42 That's an excellent observation Dave. Info like that sets my mind at ease. My concern over the blueing has never been asthetic. All the banter over dangerously lean air/fuel ratios gets to gnawing at me when I see my iridescent blue/gold head pipe. I've been throwin jets in hotrods for over 50 years and I know in my heart of hearts that I'm not running lean. My dyno time confirms that too. So maybe its not such a good idea to immediately start throwing bigger jets at a blue header pipe. Other checks are in order, like a quick look at the spark plug, an evaluation of throttle response for surging & backfire through the carb, a quick check of the idle mixture setting, a good listen for pinging/knocking under heavy load, checking for retarded ignition timing, etc. As far as heavy traffic goes, many of us have no choice. The roads and freeways on this little island can turn into a parking lot in no time flat. Sometimes you just gotta live with traffic. That's one of the reasons I ALWAYS try to run my mixture on the fat side. Of course, I also like as much power as I can muster so 12.5:1 thru 13:1 is usually my goal. |
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Title: Re: After glow? Post by ohiomoto on 04/02/19 at 07:42:31 73757A06040307370 wrote:
OMG...Someone on here who actually thinks about what's going on with their bike instead of just throwing a set of jets because everyone else on here says too. |
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Title: Re: After glow? Post by batman on 04/02/19 at 23:13:22 I 'm guilty of running on the fat side for a completely different reason, having a 95 (or older ) bike , comes with the chance of damage if to lean, from not being equipped with the starter anti-kick back gear. Running slightly rich , I never have anything more than a weak poof at shutdown ,thus little chance of blowing out the left side case or damage to the starter or it's gear train. |
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Title: Re: After glow? Post by Zook on 04/04/19 at 15:53:49 All very interesting. I pulled the plug on the air fuel mixture screw. I don’t know if I have termed that correctly. I opened it the suggested number of turns from this forum. Because it has been suggested on here that the bike is set up to run very lean. I wonder if I should just turn it back a half turn and see if this doesn’t ease up how hot that catalyst is getting. The catalyst is supposed to get hot if I understand correctly how they work. I just swonder how hot is too hot. |
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Title: Re: After glow? Post by Panhead on 04/04/19 at 17:47:03 Getting back to basics, I trust a spark plug inspection as a good indicator of fuel mixture. Yeah, I know that's old school, but it still holds true. |
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Title: Re: After glow? Post by justin_o_guy2 on 04/04/19 at 21:59:13 Old school ways with old school technology. Carbureted engines and spark plug clues are reasonable. That's not saying you ain't a dinosaur, |
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Title: Re: After glow? Post by batman on 04/04/19 at 22:37:28 I guess I'm guilty of suggesting larger jets if the pipe is bluing badly, but the Savage is known to be running lean from the factory, and in many cases, new owners are swapping to more open mufflers and cone filters, both of which will require an increase in fuel , and I almost always ask for details of how they intend to set up the motor, and their elevation. I do understand that pipes can also blue from running to rich as well as to lean, and reading the sparkplug is a good indication of proper jetting. |
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Title: Re: After glow? Post by DragBikeMike on 04/05/19 at 00:05:38 That's kinda what I was getting at when I posted my 3/31/19 comment. Where does this mixture vs pipe blueing tale come from? The folks at Lycomming, and Pratt & Whitney, and Continental, all aircraft engine manufacturers, certainly have deep corporate knowledge regarding the affect of air/fuel ratio on exhaust gas temperature. They have all sorts of graphs and operating instructions that state EGT is highest at stoichiometric. So if the mixture is lean, or if it is rich, the EGT is supposed to be lower. Why would a lean mixture, or a rich mixture, cause the pipe to blue? Seems to me, if you have your mixture spot on, the EGT will be highest, and that's where your pipe turns color. I sort of view my iridescent blue pipe as a badge of courage. It shows that for a brief moment in my motorcycle's life it actually had an air/fuel ratio that was perfect. |
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Title: Re: After glow? Post by justin_o_guy2 on 04/05/19 at 04:08:20 Stated clearly more than one time. I didn't have a blue pipe until I was sitting in the driveway, listening to the valves, at5,000 miles. Our double wall header gets way hot sitting still with a dude twisting the gas. |
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