Hard Starting Jims 120 - Harley Forum

phil · #1 07-04-2009, 12:54 AM

Hi there looking for a bit of help. I am running a Jims 120 in my Fatboy, runs great however cold starts are a problem. If motor does not fire on first revolution after popping the compression releases then it will not turn until release buttons pushed down again. This may need to be repeated 6 - 8 times before starting. In the middle of this there is the inevitable backfire that I am sure will break my starter pinion one time. When hot it only needs to turn once to fire most times. Battery is connected to a battery tender recently not having any effect and holds good voltage so I guess that is not the problem. I have had differing stories re heavy duty starters. If connected to another battery for starting it is great, but not really practical. Appreciate your comments knowledgeable ones.

frisco-rigid · #2 07-04-2009, 05:33 AM

Hi Phil

Lil Suction Cups 127" did the same thing with the 2.7Kw starter but it prob wouldn't matter if it was a 3 or more.. Once the C'R's close,, the starters have a very diff time spinning the motor..
Here's a couple tricks..

Remove the C-R's and you'll see 2 Compression Relief holes on opposit sides of the hex head..
I think their size is about .118 +-.. Not quite 1/8"..
Very carefully drill 1 or 2 more holes into and thru the Hex head.. I sugg 2 in each..
Be careful to NOT drill into the shaft.. A wee contact that just nicks the shaft is No big deal at all.. I nicked each one, just try to nick them as little as poss..
I drilled 2 more holes in each C-R.. That did the trick..

Blow them out and re-install.. Remember a wee bit of NeverSeize on the threads cuz you're screwing into Aluminum..
It will allow more comp to escape giving more spin to the motor but don't worry,, they close up tighter than a Bulls Ass in Fly Season once the motor starts..

Also this..
When starting Dis-engage the clutch..
There is No reason in the world for the starter to have to spin the clutch pack/hub and main-shaft.. Especially when cold and the tranny fluid is thicker too..
That saves a wee wear & tear on the starter and a wee bit of Batt juice too..

BTW,, I have Kick-only on my 120"..
I must leave the C-R's closed cuz I need that comp to kick-start..

That Starting back-fire could be from too much "idle" advance kicking back.. And I've always adjusted in a wee Rich Idle A/F mix for starting..

Have a ball

cpooser1 · #3 07-05-2009, 06:49 PM

I have a Jims 131" and the only time I have a problem is when the compression releases are acting up. I tried cleaning them, but that was a short term fix. I just replace them now. I did wear out my stock starter, so I installed a Screamin Eagle and a high amp battery and it really starts nice now. You can also gear it down. I haven't bothered to do that yet, as I don't think I need to. I will try drilling more holes in a set of CR's and see how that works. It seems like a goo idea.
Chris

phil · #4 07-06-2009, 01:52 AM

Thanks for the comments guys. The dis engage clutch comment is interesting. I still feel that there is too much juice getting lost between the battery and starter. I feel that I need to follow this through before I touch the CRV's.

cpooser1 · #5 07-06-2009, 10:25 AM

Phil,
Frisco is right. When I had the stock battery and my stock starter was starting to show signs of weakness, the disengaged clutch made the diiference. Even with all of the new stuff, I still disengage the clutch.
You may have sticking CR's, and new ones may solve your problem. If they are sticking they just don't close fast enough. I bought some CR's, a little different than Jims, but they work great. They are on Ebay for $21.99 auction # 370185250137. I had to modify a socket to install them, but I bought 2 sets to try and I will definitely be buying more of them.
Chris

frisco-rigid · #6 07-06-2009, 02:22 PM

CPoos

I didn't think there would be a reason to post again here until you said this--

"You may have sticking CR's, and new ones may solve your problem. If they are sticking they just don't close fast enough."

Uh, Well, closing tooo fast and soon is Phil's problem..
Drilling the extra "compression relief" holes will enable the CR's to remain open longer and give a wee more time for the motor to start..

I bet you typo'd something there huh, cuz you understood that in your first post..

Have a ball

cpooser1 · #7 07-06-2009, 08:18 PM

Frisco,
I didn't. I am serious. When my CR's start sticking, I have a much harder time starting my engine. I like your idea of more holes and will try that soon.
Chris