Jump to content

Number of cranks?


Trebor

Recommended Posts

How many times should I expect my engine ('98 1100) to turn over when starting cold? Holding the throttle advance open, of course. After I did my valve adjust, running at cold is much smoother, but it still takes 6-7 turns to get started.

 

thanks

Link to comment

6-8 rotations at cold start is normal. This begins to pressure up the lubricatio system and prepares for firing after several trip of both pistons to TDC on the compression stroke. You're fine. Hot starts occur much quicker.

Link to comment

When cold, I have found that my 99 11RT starts fastest if I hold the starter for about 1 revolution; let go; wait for the engine to stop turning; then push the starter again. On the second try it starts instantly. When hot/warm it starts instantly on the first try.

Link to comment
Pete Darby

I do what Green RT does with my RTP. Turn it over once for a second. let up than it starts right up on the second push. Probably three or four seconds if I try to force a cold start on the first push confused.gif.

Link to comment
ShovelStrokeEd

Not really unusual. The mixture created by the injector pulse is likely to be a bit lean on the first couple of revs as the droplets will tend to fall out of suspension and there is no heat in the combustion chamber or ports to help them vaporize. Liquid gasoline doesn't burn, gas vapors do. Coupla cranks and evaporation will have provided sufficient gasoline vapor in the chamber for it to ignite. There is no delay built into the process except that already mentioned.

 

Yo

Link to comment
How many times should I expect my engine ('98 1100) to turn over when starting cold?

 

There seem to be two "normal" methods for an R1100 cold start: (1) press and hold the starter for 6 to 8 revs, (2) Engage the starter for 1 or 2 revs, stop & wait a second or so, engage the starter again for 1 rev.

Link to comment
Not really unusual. The mixture created by the injector pulse is likely to be a bit lean on the first couple of revs as the droplets will tend to fall out of suspension and there is no heat in the combustion chamber or ports to help them vaporize. Liquid gasoline doesn't burn, gas vapors do. Coupla cranks and evaporation will have provided sufficient gasoline vapor in the chamber for it to ignite. There is no delay built into the process except that already mentioned.

 

Yo

 

Ed is always right. Also, we are beginning to see some of the combustibility issues regarding ethanol. Ethanol oxygenated fuels tend not to ignite as well cold as the good (bad actually...MTBE is poisonous), old MTBE oxygenated fuels (an RVP issue).

 

The continuous cranking for 5,6,7 or 8 turns does no harm. In fact, I prefer this to an immediate fire up so as to get some oil pressure before infernal combustion takes place...a good thing.

 

Also, even this AM in the Houston warmth (it was about 72 F. when I started the bike) the engine stumbled and stopped on the first fast idle detenet. Another press of the starter and all was in harmony. A well tuned bike will fire without problems whether hot or cold. The number of turns is temperature related only....no cause for concern.

Link to comment

When cold, I have found that my 99 11RT starts fastest if I hold the starter for about 1 revolution; let go; wait for the engine to stop turning; then push the starter again. On the second try it starts instantly. When hot/warm it starts instantly on the first try.

 

Is that because of the fuel injector has a sec. or 2 to prime the cylinder?

 

i'll have to try that one. cool.gif

 

well, I guess I should of read the rest of the posts dopeslap.gif Ed pretty much summed it up!

 

Link to comment

Is that because of the fuel injector has a sec. or 2 to prime the cylinder?

 

Don't think so. My FI'ed K75 always starts with the first crankover, everytime, hot or cold so injected bikes can be made to start easily. On the R11xx's, I suspect that the fuel injection computer's cold start enrichment program setting is just set too lean for environmental reasons. The start-stop-start procedure probably is just a way of fooling the computer into injecting a bit more fuel into the TB's.

Link to comment
ShovelStrokeEd

BTW, it is important that you wait a few seconds after turning the key. At least long enough for the fuel pump to stop. The purpose of the pump first starting is to pressurize the fuel rails, after which, it will not start again till it receives a pulse train from the Hall effect sensors. Going immediatly to the starter button after turning on the key will defeat this and could lead to extended cranking interval. There is no fuel pressure sensor, the pump is just told to run for a couple of seconds and then shut off.

Link to comment
Joe Frickin' Friday
There is no fuel pressure sensor, the pump is just told to run for a couple of seconds and then shut off.

 

Here's the weird thing:

 

1. Turn the key on; pump runs for a second or so.

2. Turn key off, then on again; this time, the pump only runs for a fraction of a second.

 

Does the Mo have a timer that's paying attention to how long since the last key-on event?

Link to comment

Thanks, all. I generally spend the time when the fuel is pumping making sure everything is buttoned down and my head is on straight (with the exception of a side-stand mishap wink.gif). I assumed that a fuel injected bike would start like an auto, but I'm glad to know that TADT.

 

cheers.

Link to comment

Archived

This topic is now archived and is closed to further replies.

×
×
  • Create New...