BMW R1200R R1150R/T F800 K1200R R1100R/T R1250R RnineT Message Board

Hi, can someone put me right and the reasons why? In my manual it says to ride the bike immediately after start up and not to warm it up first? Is this correct? I thought it would better to get the oil round before putting it under load???

Regards

You Do want to let it warm up some but not alot. Start the engine and let it run maybe 20 to 30 seconds---enough to where the oil pressure is up and you know it's circulating.(easy to tell---the engine stops knocking!) An air cooled engine warms up pretty quickly as there is no coolant to carry off the heat. I start mine and let it run just enough to let the engine smooth out and then drop it in gear and pull off. I run the bike fairly gently till I know it's at operating temp or pretty close to it.
It doesn't take long for the engine to get really hot when there is no air flow around the cylinders. Also since the R is fuel injected you don't have the cold running driveability issues you have with conventional carbs.

Just start it, let it idle for 10 or 15 seconds and go (gently at first!)



wayne

I once lived right next door to a Harley owner. He would get up on Saturday morning for his weekly ride and start his bike in the driveway at about 6AM. At about 6:30 he would go out again and do something to it...It had been running the whole time...and then go back inside for a while, as it continued to run.
One morning I walked over and asked him why he let it run so long sitting still like that. His answer was simple: "Let'n it warm up."
I found out later its the carburator that need the warm up. If you start the Roadster up and let it "warm up" like that, pretty soon you can roast marshmellows on the headers.

Boxer--

I have a co-worker who had a carburated Sportster. He had to warm his up for a good 10 minutes (or so he thought) before he could get it to move. I would kid him about it because we would start our bikes at the shop at the same time and I would be across town and home before he could get out of the parking lot. He now has another HD but it's fuel injected.

Many of my co-workers ride HD's and so many of them think they need to sit and let them warm up for such a long time. Hate to think what they're doing to their engines.

Long enough to put your gloves on is about right.

Thanks guys, I like the remark "you know when its ready when the knocking stops"

In my manual it says to ride the bike immediately after start up and not to warm it up first? Is this correct?

Yes, it is!!

Your engine oil is pressure fed/squirted everywhere inside the motor about 5 seconds after the red oil pressure light goes out. In really really cold weather, maybe 10 seconds.


Those H-D riders warming up their engines (a HALF HOUR???!!!!) are allowing an EPA too leanly jetted carburetor to slowly wear out the engine. With an extended warmup, the rear cylinder to crankcase joint will eventually show oil weepage and can get warped, requiring re-machining. The worst part is that a cold idling engine, with a slower warmup, generates much more blowby condensates. This is because the cylinder air pressures at idle are barely high enough to pneumatically seat the rings. Tech articles describe how cylinder gas pressure pushes the ring to the lower surface of the piston's ring land and also pushes on the ID of the ring, expanding it tighter against the cylinder walls. The piston ring's spring tension is not enough to seal the gas pressure in. The gas pressure behind it is many times that force. The fix for the Mikuni carb is one size larger pilot jet and uncovered access to the idle mixture screw . . . 1 hour tops.

For our OilHeads . . . Start it up, wait at most the time enough for helmet and gloves on, then GO!



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riceburner wrote:Long enough to put your gloves on is about right.

That is exactly what I do.

Wait a minute.....did i just read that CycleRob was giving advice to HD riders on how to improve the lean condition on their bikes via adjustments to their Mikuni. I think I need a drink......barkeep......

Al, The 2 best modifications H-D ever did was the changeover to Electronic Ignition and the Mikuni CV (Constant Velocity) carb. They were too many years behind the Japanese bikes in getting a clue on the genuine cost/performance merits of both systems. Those 2 upgrades (EI & CV carb) instantly made them start immediately and run much better than before with the stovepipe POS they called a carburetor.

The EPA standards made them jet the Mikuni's Idle/LightCruise circuit so lean that many of them idle roughly, falsely mimicking the idle of performance camshafts. What's really happening is the front cylinder runs 95% of the time and because of the uneven 405/315 degree firing interval the rear cylinder ignites the too lean idle mixture about 40% of the time. I heard one 2 days ago in the grocery store parking lot and it sounded like it was running on 1 cylinder . . . . like a really wacked out carb synch . . . . . but they only have 1 carb.

On most H-D's you cannot adjust the pilot screw rich enough to eliminate the idle misfires and part throttle cruise flatness/hesitation, but a larger pilot jet fixes that. No more 5 minute idle warm-ups.

I've worked on CV carbs since they came out on my new 1971 CL-450 Honda. I was immediately fascinated with the vacuum operated slide piston design and how it perfectly metered the fuel at any throttle opening, no matter how fast the throttle was opened. I eventually learned the fine points of how the 3 circuits (pilot jet, slide needle & main jet) overlap, so I could make very subtle small changes to dial in perfect driveability without going too rich. That's the important part. Too rich, besides being wasteful, shows up as sluggish running when it's hot-n-humid out. Riding off with a cold engine conveys the info needed, revealing all the weak points, to make only the right changes. My 1150R is my 1st EFI bike and I can honestly say I've never missed those old carburetors.

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CycleRob wrote:

In my manual it says to ride the bike immediately after start up and not to warm it up first? Is this correct?

Yes, it is!!

Your engine oil is pressure fed/squirted everywhere inside the motor about 5 seconds after the red oil pressure light goes out. In really really cold weather, maybe 10 seconds.


Those H-D riders warming up their engines (a HALF HOUR???!!!!) are allowing an EPA too leanly jetted carburetor to slowly wear out the engine. With an extended warmup, the rear cylinder to crankcase joint will eventually show oil weepage and can get warped, requiring re-machining. The worst part is that a cold idling engine, with a slower warmup, generates much more blowby condensates. This is because the cylinder air pressures at idle are barely high enough to pneumatically seat the rings. Tech articles describe how cylinder gas pressure pushes the ring to the lower surface of the piston's ring land and also pushes on the ID of the ring, expanding it tighter against the cylinder walls. The piston ring's spring tension is not enough to seal the gas pressure in. The gas pressure behind it is many times that force. The fix for the Mikuni carb is one size larger pilot jet and uncovered access to the idle mixture screw . . . 1 hour tops.

For our OilHeads . . . Start it up, wait at most the time enough for helmet and gloves on, then GO!
.

I find the HD warmup ritual interesting because the riders I have observed believe in at least a 15 minute warmup. I was talking to one of these guys the other night while he warmed up and noticed evidence of oil leakage around the rear cylinder base. I knew that the base gasket oil leaks were common on the Evo engines, but this guy seemed to think it was just a gasket change. Whatever we think about the reliability of our Beemers, the HD owners never cease to amaze me with the amount of fairly serious maintenance they're always doing.