Is running the engine without riding harmful?

Hey guys I'm after someone with a very scientific brain here as Google searches only tell me about environmental impacts.
Basically I was watching an interview yesterday with a brilliant engineer allen millyard, he's got something like six bikes and the interviewer asked if he charges the batteries or runs them, gets them warm once a week to keep them in good shape and he said no! just running the engine is the absolute worst thing you can do! He said engines produce a mild firm of sulphuric acid which fills up the engine and exhaust, he said if he starts a bike he then rides it 5 miles minimum as a rule, otherwise he leaves them and just opens the fuel tap every so often so the carbs don't dry out and to stop the needles blocking.
Anyway I remember my old pal dougie trying to tell me about acid produced by running engines and how 1 gallon of fuel burned made quite a lot of acid!
Anyway can anyone give me more specific detail on this, and the seriousness of it, I must admit I generally run my Z1000 for 15 mins 3 times a month then do a 50 mile ride at the end of the month! I've been doing this about 3 years!!! Thanks guys :laugh:

I never run my bike unless I'm going to ride it. The heat creates condensation which is damaging unless you are going to run the bike and burn it off. Mufflers in particular get a lot of water in them, which is why drain holes are added to help drain it off (only the drains tend to clog up with rust flakes so keep those clear if you can.) I've never heard about acid build up before. Acid is a byproduct of combustion, which is why motor oil has acid buffers in it as an offset. Anyway, no running for me. OEM's typically recommend putting the bike up during winter and not running it so that should tell you something.

Riding it is definitely the best way to go. Getting the engine to operating temperature and burning off moisture. 15 minutes doesn't sound like a lot, but I cringe sitting at a light for just 5 minutes with an air cooled engine. If idle and not moving is the only choice, be sure to run a fan on it.

Riding the bike once a week is the best way to keep everything up to snuff. However, I run my KZ650 engine for about 10 - 15 minutes once a week all winter long without actually riding the bike. That allows the engine oil, etc. to get hot, the cylinder walls to be coated with fresh oil, and the battery to stay charged. I've owned my KZ650 since 1977 and have done this for more than the past 35 years. My bike still runs great, has never been rebuilt, has the original exhaust, etc. Maybe this is not the very best way to keep the engine in tip-top shape, but it works fine for me. Below are a couple pictures of my bike. Ed

An idling engine runs rich. This leads to carbon buildup if it becomes excessive.

One of the byproducts of combustion is water vapour, which when mixed with another byproduct, SO2 , creates sulphuric acid.

Thanks for all the input guys just to be clear my warm up routine is usually choke for 30 seconds then switch it off while rolling the throttle on slightly, then I hold it at 1500rpm for 3 to 5 mins by then the engine tone has changed and it's cleaner and smoother sounding, I'll then Rev it between 5 and 6000 four times and see what the idles like, it's usually 900 odd at this point so I hold it at 1500 rpm for another 5 mins, afterwards the idles between 1000 and 1100 and it sounds like it would idle all day long so I leave it 2 or 3 mins then shut it off. Ideally I should just warm it up then go off for a ride but i can rarely get to my garage which is 20 miles away and when I'm there I have all kinds of little jobs to do on the bench and things to organise, the poor bike only gets attention in the last 30 mins before I go home!!

I have always been on the fence when it comes to starting the bike during the winter months but not being able to ride it for a longer period of time. So personally my routine is when I know it’s that time of year, I will fill the tank add a good marine grade fuel stabilize., Ride the bike for 5 to 10 miles to make sure that all the fuel stabilizer is mixed throughout the system Typically I will shut off the fuel cock about two blocks from the house and if it has not stalled by the time I get in the driveway I let it idle until it stumbles for the first time and I shut it down. Typically I will drain one fuel bowl to make sure that all of the gas is out of the hoses and filter. Plug in the battery tender, throw a cover over it, and go to bed dreaming and waiting for the next first warm spring day.

That sounds good it's funny because I've had conversations with people who rode zeds as their only transport all year round when the bikes were between 1 and 5 years old and I guess that's no different than buying say an mt-09 now and doing the same, but if you live in a country with four different seasons it would just seem a bit mad to put a classic Z through that now! I suppose it's the problem with things becoming valuable, especially if you earn a real basic wage like me! It's all too easy to jump in the diesel Jetta and only bring out the bike when it's nice!! :laugh: :laugh:

One gallon of combusted petrol produces over 1 gallon of water which also contains the exhaust byproducts which form a corrosive cocktail.
The main thing here, whether riding the bike or just giving it a mid winter clearout in the garage to run fresh fuel through the carbs to prevent gumming etc is to run the engine long enough and hot enough to evaporate any excess moisture in the exhaust AND the crankcases.
Short start - ups and low idling are the exhaust killer ( unless it's quality stainless ) and also not good for the engine internals and oil.
If the weather is too bad to ride and the bike needs to be run then once started and off choke get it HOT with plenty of revving and high idling .
Around 10 minutes from initial start up will do the trick.

I'd be more concerned with dry starts if left sit too long.
Steve

650ed wrote: Riding the bike once a week is the best way to keep everything up to snuff. However, I run my KZ650 engine for about 10 - 15 minutes once a week all winter long without actually riding the bike. That allows the engine oil, etc. to get hot, the cylinder walls to be coated with fresh oil, and the battery to stay charged. I've owned my KZ650 since 1977 and have done this for more than the past 35 years. My bike still runs great, has never been rebuilt, has the original exhaust, etc. Maybe this is not the very best way to keep the engine in tip-top shape, but it works fine for me. Below are a couple pictures of my bike. Ed

Nice bike, Ed.

I think the best theory is F&^% the battery. Or use a trickle charger. Run Sta-Bil through the carbs and drain the bowls after shutdown. Then don't start it until you're ready to ride the B%^$%.