Me and a buddy went to Eureka Springs on Friday and it was hot hot hot. No problems with any of the hot starts. I've been riding every day since and still no problems!

 

Back to the same ol $h1t. Missing, coughing, backfires, and etc. Any new advise out there? I've heard compensator in a couple places now...

 

Doubt the compensator has anything to do with it ... the compensator is a means of 'spring loading' the sprocket on the motor's output shaft (drive shaft) so as to make the ride feel less abrupt when taking off and when shifting gears ... it will 'give' a little when releasing the clutch and make the drive feel smoother ...

When you are starting the motor, the jackshaft extends the pinion gear to engage with the ring gear on the clutch basket ... then the starter motor drives the motor to turn over via the primary drive and the motor 'hits' and power then comes from the motor ...

When the starter drives the motor, it should not matter whether the compensator allows the motor to lag momentarily ... the electronic sensors that detect the crank position and the other inputs are what signal the ECM to inject fuel and the ignition coil to send a pulse to the spark plugs ...

* * *

Not sure where to go with it ... just thinking through the compensator angle ...

Maybe the Idle Air Contol (IAC) ... sometime some carbon can foul the IAC port ...

When the EFI motor is started, the butterfly throttle plate is closed and the IAC allows air to pass from the A/C side to the intake manifold side ... the IAC program senses the head temp and allows the appropriate quantity of air to pass through based on temp ... if there is an obstruction or if there was a problem with the IAC itself ... could cause problems with starting ...

Another possibility is that there is a manifold leak ... and therefore, the motor is running lean ...

Good luck ... post up if you find the solution ....

R/
'Chop

 

All good ideas, but... I have the ability to, and have changed, the starting fuel ratio's manually with my tuning program and for a while it fixed the problem. By manually adjusting and dumping more fuel in at certain (hotter) temperatures, I have eliminated any lean conditions that may have existed.

A leaking manifold, which is getting worse, could explain it...

 

A leaking manifold will cause a lot of problems.

 

My first thought was the IAC, but when you said you had a leaking manifold that's something you need to get fixed before you do anything else.

 

My 07 SB had this grinding sound issue / difficult starting. I had trouble replicating at dealer so they pushed back and wouldn't replace the starter. Finally one week after my warranty expired I was able to replicate the issue at the dealer. After much back and forth, getting HD local service rep involved (who tried to blame my stage 1 upgrades) the dealer agreed to replace the starter but I had to agree to pay half.

Since then the grinding has never reoccurred but when hot I do have some issues with difficult starting. It seems that when hot and starting it acts like the battery charge is low at times and get the motor to turn over is sluggish even though I always keep the battery on a tender. The battery is the original HD Battery. This only happens when hot.

Since the original battery is almost 5 years old I purchased a new battery (AGM from Advanced Auto Parts / 270 CCA) last weekend. I haven't been able to put serious miles on the bike to see if the issue has improved.

 

My 07 Street bob also starts hard when hot and grinds on occassion. Dealer just shruged and said they do that sometimes. Bullsh!t!! I was going to replace starter but don't want to spend money if its not the issue. Also just noticed an odd squeak at certain rpm's. It occurs when bike is sitting idle and reved up and when in motion. Sounds like its coming from primary, but not sure.(Sorry to hijack thread). Just wonder if compensator could be reason for both issues.

 

We addressed the compensator earlier in the thread. I don't know if you saw that or not... As far as the dealer, I sometimes just put my boot in peoples a$$es too. Seems to be a huge problem for the SB's...

 

Same problem on my 2007 FXDC. When hot like after stopping for gas, it will sometimes grind like on a car when its already running and you turn the key to start again.

If I drop it into gear and try to roll it back and forth and then put back into neutral and then hit start, usually no problems and will start right up. Not sure if there is a mechanical reason or just randomly works.