Is it okay to operate a 6 speed 2008 Electra Glide at 100 kph (10-20 kph over the speed limit here) or should I use 5th to ensure the engine isn`t lugging? If I should be using 5th at those speeds, what could happen if I use 6th - would it cause pre-ignition or detonation due to carboning up the engine or.....? I believe the engine turns 2150 rpm at that speed in 6th, and maybe 2500 rpm when in 5th, which I would think would be harder on fuel and is spinning the motor faster than necessary (so it`ll wear out that much sooner). I`ve been told two different things by four different Harley service departments. One pair of dealers says anything over 2000 rpm is fine, which implies 6th is okay at 100 kph, but the other pair say only use 6th for 120 kph up, as you can damage your engine if you don`t. The latter appear correct if my just cracked/broken piston and scratched cylinder ruining my upcoming mega trip are any indication, and he says it`s due to pre-ignition caused by using 6th at 100 kph and/or bad fuel. I`m not sure what to think because I used premium or boosted regular all the time, and got pinging on premium, worst in Yellowstone but had a mild tinkling sound off and on much of the trip and it`s a stone stock bike. I`m having a new piston and matched cylinder sent by next Thursday, eating into my trip duration, however I`m very concerned the same thing will happen even if I do run 5th from now on....because I`m quite sure I had pinging even in 5th, which I tried one time to avoid the pinging to no effect.

If I still get pinging in 5th while running premium, I`ll have to sell the Harley I hate to say, as I loved it while it ran for the one and only 20,000 km trip I took it on, where it ran perfectly but for burning 1.5 L of oil per oil change and the pinging. Really not a hitch, smooth and 45 mpg CDN, through to parking it for winter. But I`m extremely disillusioned and frustrated with them now, paying a LOT of money only to have this happen, which I`d expect out of a used 2 stroke snowmobile, not a huge low powered/stressed low revving 4 stroke roadbike with a mere 29,000 km. In the bike`s defence I didn`t winterize, though put new plugs, clean filter and fresh treated gas in while troubleshooting, but I don`t believe that would crack a piston (just cause poor idling/starting/running). The bike would only start and idle without the air filter on, but had 10 psi in the lead cylinder, and I actually drove it a ways without the filter just to get it shipped to a dealer so it ran but blows all kinds of mist out the breather tubes due to the cracked piston apparently. The valves are all okay, as is the rear cylinder which has good compression and they peered in with a camera and it was okay, so I`m lucky there I guess. It ran, started and idled perfectly with the filter on last fall, but wouldn`t start without WOT in the spring and when I finally opened the throttle there was a scary grinding/clunking sound and it roared to life but wouldn`t idle without throttle, but I chaulked the sound up to running WOT for a second on 1 cylinder, though now I know that must have been what broke the piston and scored the cylinder. I feel silly now of course, but its like a new bike, I thought it was impossible merely starting it would break the piston, since you`d think it would break under load. For the record no, I didn`t keep it WOT for any length of time at all, it was only to get it to fire a couple times and I released it. I do it on snowmobiles all the time, and it shouldn`t break the piston. Besides, it wasn`t starting with no throttle after much cranking.

Thanks in advance.

 

Deleted because accidentally posted the same thing twice

 

Sorry - accidentally posted twice. I saw after posting that I should introduce myself in the New Member section so just did. I appreciate any advice, especially since it`s free, so thought that`s the least I could do.

 

You can edit the second post and delete it.

In answer to your question, the addition of a 6th gear by Harley was done to help them get the bike through current noise emissions regulations, by reducing engine revs at the road speeds the tests are done at. It is not there for our benefit! Harley will probably tell you it is fine to run at very low revs, but to some it is not being very sympathetic to the engine!

On my old five-speed bike top gear gives just over 22mph per 1,000rpm, so 60mph for me is 2,700rpm. I am quite happy running my bike at speeds up to 90mph, where roads allow, which is just over 4,000rpm. IMHO that is not excessive an engine speed, bearing in min the engine is designed to run at over 5,000rpm.

So your bike is not going to suffer any harm running at 60mph in fifth. It is going to have an easy time and fuel consumption shouldn't suffer, whereas riding at very low engine speeds is more likely to hurt both the engine and your pocket.

 

You certainly seem to have been unlucky with your bike, I've had nothing like that level of problems with any of mine. The worst I've had is having a lifter go at 12,000 miles on the Dyna so I can only report good experiences.

I would not recommend going into 6th until around 70mph at least and preferably 75mph (120kph). The engine just feels horrible doing that, I also feel its a poor gear to use for any kind of acceleration as it's so tall a gear. I think you'd get less pinging keeping the revs up but it might be sensible to fit an aftermarket system like a PC V to enable the tune to be tailored to your specific bike. Fuel consumption tends to be best with the RPM over 2500 I think (although I've not done any tests). Running the bike between 2500 and 4000 is better for it than running it at 2000 to 3500.

 

Thanks (I deleted as best I could without seeing any `delete` button above).

And here I thought Harley was giving us extra value! I also thought the intent was to improve fuel economy, assuming fewer revolutions per minute only logically would burn less fuel in a given distance, not to mention the engine would last that much longer given there are fewer revolutions for a given mileage. I never thought turning higher, like 2500 rpm or more in 5th, would be hard on the engine. I just didn`t think 2150 in the provided 6th gear would destroy it! Especially when it appeared to be loping along quite smoothly/contently. The stereotype of Harley`s is that they`re low revving torquey tractors and many people purposely lug them to get that galloping exhaust note. I prefer the calmer less frenetic feel and sound at 2150 rpm than 2500 rpm on the highway, despite losing the throttle response if you want to suddenly pass for which I sometimes geared down to 5th for if I was in a hurry but otherwise accepted the slower acceleration to eliminate the need to wake my foot up from its relaxing vacation to down and then upshift from its comfy perch on the highway pegs. Anyway, I don`t consider 2100-2200 rpm `very low speeds` but to be safe I still won`t do that anymore.

Maybe it won`t hurt fuel mileage to run at 2500 rpm plus in 5th, not that at this point I care about fuel mileage like I used to. I just want a bike that won`t cost my $2000 in repair bills for cruising at rpm`s I didn`t consider to be lugging since they were a couple hundred rpm over the 2000 rpm most people say lugging starts when on flatish roads. At this point worrying about fuel mileage is petty compared to destroying engine parts. So even if it burns more fuel, I don`t care, but it would be a bonus if I can have my cake (mileage stays close) and eat it (runs better, performance AND reliability wise) too. Frankly they do sound pretty good at 2500 rpm too, and is probably something I`d get used to, which is hard when you`ve gotten used to the calmness of 2150 rpm. True though Harley`s have always run at this speed, before the advent of 6th for emissions reasons and/or maintaining 2500 rpm at higher 70-75 mph speeds, so why change something that worked so well for so many decades? I just wish I hadn`t had to learn the hard $$$ way, but two dealers said 2000 rpm is fine and two said it`s not, so it`s hard for a new rider to know who to believe, especially when you assume those that said its hard on it didn`t mean something this dramatic could happen and so quickly (first trip).

 

Yes that`s the speed (120 kph) I heard a couple mechanics suggest should be when you snick it into 6th. But two others said lugging starts at 2000 rpm and not to worry so I didn`t. I just didn`t know who to believe so chose who I WANTED to believe. That being those who felt running it at the calmer 2150 rpm like I preferred for what I thought was better fuel economy and longer engine life would pose no problem whatsoever.

It`s interesting that fuel economy would be better at higher revs, but hopefully that`s true or it`s at least close or the same, since that`s where`I`m running it from now on whiel cruising. Though I never felt the engine felt anything close to `horrible`while down at 2150 rpm, but maybe that`s a subjective thing and I`m not very mechanically sensitive! So rule of them from now on will be 2500-4000 rpm, and I bet I`ll have more fun riding it now too, kind of like a win-win situation.

 

....if I have to replace a 96 ci piston/cylinder anyway, does anyone think now with the engine apart would be a good time to:

a) Add an oil cooler to keep temps down which may have contributed to detonation which may have led to pre-ignition which cracked the one piston? Also should I run synthetic oil to keep the engine cooler yet? Actually that would only prevent oil breakdown, not cool the engine though one dealer told me the latter.

b) Add a Screamin Eagle 103 ci or 105 ci kit? Would that cause me even more reliability grief than the stock 96 ci? I realize it`d add even more labour, for the second cylinder/piston plus a cam change and whatever else (clutch upgrade?). I heard the 103 or 105 is better reliability wise than the 110.

 

See below youtube video on detonation vs pre-ignition, the latter of which the dealer owner/mechanic belives caused the failure. After watching this video I think both cylinders were detonating, starting at about the 50 second mark before which they`re only talking about spark plugs, which made it run very hot which caused pre-ignition, which broke the piston in the lead cylinder. I had to watch it a few times to understand fully but got it now. The key is to carefully watch and rewind and rewatch the slow motion operation of the detonating and pre-ignition conditions, showing the intake, compression, power and exhaust strokes. That is air/fuel mixture INTAKE (intake valve open as piston drops), COMPRESSION (intake and exhaust valves closed as piston rises), POWER (both valves still closed as spark plug fires to ignite the compressed air/fuel mixture to drive the piston down), and EXHAUST (exhaust valve opens as piston rises to expel products of combustion). Detonation is when the entire compressed mixture is so hot that it all explodes simultaneously, vs in a controlled manner originating at the igniting spark plug radiating outwards, in all portions of the combustion chamber which is like hitting the piston top with a sledge hammer repeatedly. Pre-ignition is when hot spots due to extreme heat from detonation, like a piece of carbon from some carbon deposit presumably left due to lugging the engine or running too few rpm for the gear you`re in, or a glowing red spark plug electrode/ground ignites the compressing mixture from that `corner`of the combustion chamber before the piston has reached the top to be ignited at the center by the spark plug. This can cause grave structural damage to the engine`s components such as pistons as I found out. If detonation is caused by excessive heat and/or octane, and I`m already running premium fuel, maybe I should try to lower engine temps by installing an oil cooler. Because if I fix the detonation you`d think I`d fix the pre-ignition. Maybe running it in 5th would prevent carboning up which may prevent pre-ignition despite detonation but I don`t want to take that chance. I did try running it in 5th and kept hearing pinging, but that may have been detonation and not pre-ignition. But if I don`t do ANYthing but run it in 5th I`ll still keep getting detonation, if not pre-ignition, which is still not good if its like hitting the piston with a hammer! Besides, it`ll still heat up the spark plug tip if not any carbon so would still pre-ignite the mixture and break my new piston (or the old one in the rear cylinder that lucked out the last time). Frustrating to even have to think about this on any bike let alone a `new`one with EFI and low mileage.

http://www.youtube.com/watch?v=ZWKRw0HmBLE&feature=related

 

There's many ways to tackle ping. Oil cooler is good, a programmable tuner is good too and some people have tried Xieds which are meant to richen the fuel slightly to allow cooler running - these are not too expensive I believe. Those with genuine knowledge should be able to help you out here.