Thanks for the replies guys, but most of you are missing the point. We have been discussing hard start issues with 103" motors on here for months. Many of us have had the same experience. Bike starts fine when cold. Bike is unpredictable on how it will start when warm or hot. Sometimes fires up with no issues, but the key is that some of us have been experiencing a starting problem "somtimes" when hot. Some of us have problems that it seems like the motor is actually trying to turn backwards and even blowing smoke out the breather when trying to start. This is along with the starter and motor making horrible grinding sounds when trying to start, but only somtimes.

The most common solution everyone comes back with is "add compression releases". I knew this wasn't the cure for this problem since I have compression releases and they don't solve this problem.

I was convinced it was a start-up timing issue, but after working on that, I knew it wasn't the cure either.

Now after at least 25 starts in various conditions, I am convinced it is a start up, cranking fuel issue.

It makes no sense to me that pushing the starter button before the engine light goes out it the answer, but it is working for me after several trials.

If you don't have this problem, I am not trying to convince you that you do. If you do have this problem, I am trying to share what I have learned in the last 4,000 miles of dealing with it.

It was only because of someone's comments on here that I tried hitting the starter immediatly after turning the ignition on that I tried it. I was only hoping to help others with this same problem.

BTW, I bought the bike with the street legal 103" kit in it. After riding it 8,000 miles, I added the higher compression pistons, 103+ heads and compression releases. The starting issues have been the same before and after the compression release install.

My main goal in this thread was to help those who had a 103" build without compression releases to look for the easy fix before they paid the labor to take the heads off to install the compression releases.

Dennis

 

Sorry dude, a misunderstanding. But in your first thread you didnt mention having comp. releases or am i missing some thing? Ive heard there being issues with the electronic comp. releases not the manuals. Give DALTON a PM im sure he can come up with some answers to your issue, WHAT DO YOU HAVE TO LOSE

 

Does your bike have manual or automatic compression releases? HD has had earlier problems with the electronic CR's and recently changed vendors. Maybe as said earlier, this is something for you to check?

Early on you posted I Quote:
"I would really be pissed if I had done like some have and went to the extra expense of compression releases when all that was really needed was a little more cranking fuel."

I think when you made this statement most of us reading and responding believed you didn't go to the extra expense of adding CR's.

Good Luck.
I have done some of my own cyl. pressure tests and with my CR's open I only run around 110-120PSI cylinder pressure, whereas when closed I am 185 PSI, so they do bleed off a lot of starting piston pressure making cranking easier and the motor spins faster. Mine really snort when engaged. You know they are working. I just wished my builder had recommended them to begin with when I did the Stage II.

 

I've got an 07 FLHP. HD did the cop bike auto compression release update that added compression releases to the heads for free. I've not had a single hard starting issue with my bike (07 FLHP has 103" motor stock)

 

Maybe I'm off base, but starting the bike right away when hot instead of waiting for the light to go out might mean LESS fuel is in the cylinders. I'm not sure why that would work, but I'm looking forward to giving it a try, if we ever get Spring here.

I also mentioned once before that I found it easier to start hot if the bike was in Neutral, rather than in gear with the clutch pulled in. I assumed the clutch added some drag which somehow made the hard start / backfire problem worse.

 

When you turn on the key the ecm turns on the injector for a certain pulse width (measured in milliseconds). Waiting for the check engine light to go out lets the fuel dissipate. Increasing pulse width (cranking fuel table) allows more fuel so there is still some after waiting for the light. Quote from SERT manual "engines that are hard starting usually require more fuel".

 

I haven't had issues yet with my new 103 but I do have to hold the starter but a little longer, maybe a second. Great info rochkes, thanks I'll try it!

 

My compression releases are manual. I wanted automatics, but my builder recommended I stay away from them because they aren't known for their reliability.

I can understand where I caused the confusion when I said I would'be been pissed if I would've went throught he expense of compression releases and it not worked.

I was referring to several other people on here that have been participating in 103" hard starting issue threads that have did a top end tear down to add compression releases and it didn't help at all.

I admit that I truly don't understand the fuel system on my bike. I don't know for sure when the fuel starts dumping into the cyclinders. Is it when the switch comes on or when the starter starts cranking?

Lonewolf's quote from the sert manual seems to answer and veryify what I stumbled across by blind luck and it was verified by my tuner.

Dennis

 

THANK YOU!!!! That does help me understand what is going on alot better.



Dennis

 

Wow! This solved my hard start problem. I have a big motor (see below) with CR's and it has always been hard start when it gets hot. Thanks Dennis.

Steve