Hard cold start

[64Herald]

I need some ideas as to why... If I don't start the bike for a few weeks or longer it takes a lot of cranking to start. The battery does it well but it just cranks and cranks till it goes boom then runs great. If I start it offen it's no problem. Any ideas? I was thinking maybe the fuel pump is not sarting up right away.

 

[Gothlander]

I am starting to think it maybe the oil draining back to the sump that is causing some cold start problems. Maybe check the oil is in the tank before trying to start the bike.

 

[64Herald]

please tell me more. The oil tank to low sentting off a sensor?

 

[warp9.9]

I am starting to think it maybe the oil draining back to the sump that is causing some cold start problems. Maybe check the oil is in the tank before trying to start the bike.

I do not think that matter Goth as the sump area is so big if all the oil was down below it would not even reach the crank or clutch bascket gear. The high pressure oil pump drives the scavenger pump and the water pump via the chan drive coming down from the basket. The sensor only measure pressure on the engine side.

 

[HellFire]

My opinion on why they are hard to start cold is that there are multiple issues causing it. First the fuel injection line pressure has bled off and has to be built back up. Second, cold engines have close tolerances and everything gets tight. The oil has had the chance to leave the surfaces of the bearings and nothing is floating on an oil film, start ups are when most engine wear occurs. Then there are those HUGE pistons, just think about the surface area and diameter of those piston rings, that's alot of drag against the cylinder walls after the oil has had a chance to run off. It's not a high compression motor, but that's still an awful lot of air to move and compress. Finally there is that little tiny battery, even with a high CCA aftermarket battery it is still limited by it's size.

You can get an idea of how hard it is to crank over an engine this size by putting the bike in gear and trying to push it, try a high gear to get some extra leverage from gear reduction and it's still tough to turn it over yourself. I cycle the key a few times prior to starting it after it's been sitting with the idea that I'm building up fuel pressure. I haven't put any gauges on the fuel rail to verify the theory, so I might just be fooling myself.... but it seems to help. The Odyssey PC625 battery also delivers higher voltages and CCA's and that seems to spin the engine faster and longer than the stock battery. The odyssey is a little exotic and requires extra TLC and it's own charger, so it's not for everyone. There are other batteries out there and some are new technology even better than the PC625, but that stock lead acid motorcycle battery will probably let you down unless the bike is sheltered from the cold and doesn't sit too long between startups.

Basically it's just the nature of the beast and all you can do about it is to keep a good battery in it, check and clean electrical connections, start it often and use some sort of charger made for whatever battery you are using.

Have any of you guys put a set of fuel pressure gauges on one and cycled the key? I'd be interested in knowing for sure if that method actually does any good.

 

[kmrmike]

I had a similar problem with my Vulcan; it would crank & crank & crank...and would not start. I jump it with a car battery and it would crank right up without doing anything else. It seems while cranking over the engine would bring the battery voltage down enough that the ECU would not work. I had planned to install a small gel battery on a relay system to isolate and opereate the ECU while in the cranking position only but then the R3T came along and never did it. Only thing I can offer to help is keep it on a battery tender if possible. Also those lithium ion batteries I've been reading about seem promising...but expensive!

 

[atomsplitter]

Eliminate one problem at a time to find the culprit. Check your oil level before starting. If all the oil is in the sump use a heat gun to warm the sump (I do that on my tractor that sits outdoors year round, she's a real turd to start at 20 degrees). Warm oil will take less energy to move it, leaving more energy for the ECU. If that doesn't solve it, move to the next thing, put a battery tender on it with a start cycle (50 amps or more). Keep doing one thing and see if the behavior changes, you'll find the reason eventually.

Of course you could just ride it every day and that should take of it too.

 

[64Herald]

i shot a little either under the seat and it started right up. now it's starting to sound like fuel. shouldn't the fuel pump prime the sysytem just by turning on the key?

 

[Kmutt]

Yes it should but as stated previously the lines are probably bleeding down. So turn the key to the ON position let the fuel pump do its thing then shut off the key and repeat. I would think only a couple of times should "prime" the lines ( I say prime loosely because it shouldnt need much priming) and then try to start.

Good luck!!

mutt

 

[64Herald]

today I was going for a ride. I turned the key on waited turned it off. I did this 3 times and on the last try I cranked it over It started right up. So whats going on? The pump doesn't stay on long enough to prime the system?