Mrfikser,

bike is full stock, except it has been "X-ied" in the beginnings and I've put a round 72 A/C with ditto air filter, that's all.

Exhaust full stock, no punching, no "gronking".

Very recently, the CPS and both injectors have been changed, as the exhaust and admission gaskets on the heads.

No engine "idiot light" lighting up.

46 k miles on the odo, 80% of the time riding on the highway at 75-80 MPH, commuting a daily 100 miles round trip to my work, 200 days a year, bike gets a motor oil change (half syn-half dino oil) every 2,500 miles and gets the appropriate maintenance each 5000 miles, what I call the "small" maintenance each 5,000 miles and the "big" maintenance each 10,000, each time done by my indy, who is known to be competent, except for now it seems, he knows a lot about older carbbed and pointed Shovels, Ironheads and other 1340 Evo's, but now, the guy's telling me that he is lost...

I know the coil hasn't been changed, this is why I'm following this way for now.

Thanks for the help, anyway!

 

OK guys,

new coil and HT wires put on today, with new plugs, got them on loan from my indy, trouble remains, rear cylinder still not working!

Symptoms:

- rear exhaust pipe getting hot, not as the front one which works good.
- injector apparently delivering fuel, plug is wet when I tried to start the engine.
- rear plug gives spark.
- no engine light lighting up, everything's fine for the system.

The indy is inclined to a mechanical problem inside the cylinder, bad rings, piston holed or a valve which doesn't open or close as it should do.

I'll grab on monday a compression tester at work, and compare the pressions in both cylinders, I also will pull out the rear rocker cover off, to have a look at the valves, rockers and pushrods, who knows if a lifter went bad, even if I have no rocking noise inside the engine...

Or maybe the cams?

 

And not one "mechanic" has checked for injector pulse?

For ****s sake, if it was mechanical, a simple leak down or compression test would eliminate that possibility. If you want to see if the injector is firing, you can get a "Noid light" and put it on the injectors and physically watch.

With the aftermarket 02 sensor foolers, I'd be unplugging that **** and trying it out.

Disconnect the battery, and let the ECM clear. See if that helps. The ECM might be seeing an input it doesn't like. That's why the bike needs to have the scan tool hooked up and properly diagnosed. Your "mechanic" is running out of ammo in his parts gun.

 

Good point, I didn't know that, being a dinosaur educated when bikes were fitted wih points and carbs.

My 1972 Beemer R 75/5 is tuned and maintened by myself, it runs like a champ, there is no stinkin' ECM nor a friggin' EFI nor a bloody CPS, just points and 2 carbs, and it gets me everywhere while using 3/4 of the gasoline I need to feed the Sportster, at the same speed and on the same roads...

Talking about progress, huh?

 

Remember that's where a lot of started.
It's pointless going on how things used to be, because it's not going to be like that again, ever.
Go buy a new BMW, and it won't be anything like the one you got now.

 

You're right, it seems the latest Beemers, oilheads as waterheads, show a lot of problems...

 

Wow. Something that makes 2/3 the power only uses 3/4 of the fuel? That's amazing! Wait, no, that's still technically less efficient in terms of brake specific fuel consumption.

You might as well complain about the lack of "progress" by Aston Martin since a Vantage uses more fuel than a Reliant Robin.

Look, I love the old BMWs as much as the next guy (actually, given that this is a very Harley-centric forum, probably a lot more than the next guy), but it's just not a valid comparison to take a 750cc machine and talk about its fuel consumption compared to a 1,200cc machine.

 

Maybe not, but I see a valid comparison when riding to my work at 75 MPH with the H-D or with the airhead, same job, same distance, same speed, the Beemer being less shaky than the Sportster (read: more comfy), and yet the fuel consumption is different, and that's a fact.

Now, I've been to my indy today, you know, the lost one, to loan a replacement coil and wires, as told above.

He told me he had to repair the wiring harness, where the wires meet the injectors, they were "eaten up" just as a mouse would have eaten the plastic around the cables.

I've found this harness with P/N 70167-08 on Fleabay, would this eventually be an option to solve my problem?
http://www.ebay.fr/itm/Harley-Davids...-/360765614122

 

You're still not getting it. Just the same speed isn't enough for a comparison. A Reliant Robin gets better mileage at the same speed than an Aston Martin Vantage, but that's not because the Vantage is somehow a step backwards.

The R75/5 has a smaller engine and makes less power. It should be absolutely no surprise that it gets better mileage. The Sportster also weighs an extra 100 pounds more than an R75/5. They're very different bikes and expecting a bike that makes 50% more power, has a 60% larger engine, and weighs 20% more to get the same fuel mileage as the R75/5 is just absurd.

And comparing a boxer engine (which is perfectly balanced inherently) with a shared crankpin 45-degree vee engine (which is inherently unbalanced in a big way) in terms of smoothness is likewise absurd. It's like complaining that the old British singles thump a lot. That's the nature of the bike. It's something that you know going into it. Might as well complain about a lack of weather protection compared to a car.

If the problem is, in fact, with that section of the wiring harness and the part from eBay is in good shape then yes, that could solve the issue.

 

Yes, I do, but we both know we are even stubborn, in a certain way...

Let's compare what's comparable then: I'm pretty sure a 2004-2006 rubber mount Sportster 1200 with a carb properly adjusted consums less than a newer EFI one, riding both & together in the same road conditions...

Is that OK for you, then?