1991 FXR 80" EVO. This bike has had a very slow starter turnover (struggles to turn over) since I bought it. It managed to start all summer. Thought it might have hi-comp, but don't know (haven't had it apart yet.) Ever since the colder weather set in, the motor might turn over once and thats it. Then it acts like the battery is dead (solenoid clicking). Installed new battery & 1.4 KW starter. Won't turn over!! Put 12V directly to starter post & ground to case. Starter & drive work properly, but won't turn over motor. Tried several batteries, no luck. Engine runs great as always when push start. Warmed bike up with heater, helps some but wont crank-over. Could the compression be holding this motor from turning over???? Turns over fine with plugs out, install plugs, wont turn over. HELP!!!

 

Thanks for the quiz.I think in the 90's Harley made some running changes to address this.What they did was change the gear ratio's between the pinion and the ring gear on the clutch shell and 1 other gear that escapes me,which made it easier to turn over motor.Normally,we would do 3 voltage drop tests to find the drop/extra resistance thats stopping our current from spinning the starter.From what your telling me the system is operating OK,its just not strong enough to overcome compression.That is throwing me.However,I would like to verify 1 or 2 things before we have to start worrying.Can you get a meter and a friend to hit starter for you?This wont take long,Bob

 

Bob, Thanks for a reply. I have not taken any "Voltage Drop tests" but only insured that full voltage got to the starter eliminating the bike wiring & starter relay. Yes, I do have meters, but am almost to the point that I suspect all is ok in the elec. dept., but something is marginal in the engine cam timing or something, like the valves are not opening at the right time. Like I said, the motor has very strong low end power like the cam may been advance when installed???? but maybe too much??? Nothing has been changed with the engine lately to cause this, just the colder temps. Just about ready to pull the engine down to see just what I have, as I know its pumped up some.
Never seen this in my 40yrs. exp. Any & all input is appreciated.

Lakebum

 

Yes,this is pretty unique to me also. As bike runs good,dont think its a motor[compression,timing], issue.When you say you put 12V to starter,do you mean you jumped it from external Battery?Lets say switch and relay circuits are good.1 more test will rule out a suspicion of starting system.Its nice to have a friend,but you maybe able to do this alone.
Meter on VDC,one lead[either one] to Battery + term and other to terminal on solenoid where short[2-3"] cable comes from starter.Hit starter button and observe meter.Should read 1 or less.This isnt easy to do with just 2 hands.This would [for me]eliminate all 3 starter circuits.I know its a hassle,let me know what you think,thanks,Bob...when you say you know its pumped,I will assume you dont have compression gauge or you would have stated PSI numbers,so did previous owner have any headwork done you know of?About the only other mechanical issue I can think of is a sticking jackshaft....Bob

 

The last test I made was a 12v connection directly to pos starter post from an external battery with plenty of juice & cca. Then applied 12v to solenoid post to activate, totally eliminating all other wiring including batt cables. I'm interested to try the voltage drop test next, however I'm really starting to think mechanical. Starter drive does not stick or bind. Did a comp check but due to the gauge I used and getting the motor to turn over, I'm not sure of accuracy but was in the 140-150 range.

 

Yes,I see,that helps then.I understand your thinking,but I must say this test is imperative in my view as we havent determined if were actually getting 11-12V down to solenoid using only the bikes system.That PSI is consistent with a stock evo motor,which suggests a new starter should be able to handle it.Can you tell if it has the stock cam?Adjustable pushrods would indicate a performance one as would the sound of course.Am trying to figure if we have an early closing intake....but I dont think thats a big factor either way.Could you check out that test?It would ease my mind considerably,thanks,Bob

 

Starter cables? remenber there are 3 on an FXR. Measure starter volage the starter using the starter for ground. Bruce

 

Very interesting topic, it almost sounds like you have a bent or out of adjustment push rod or something of that nature, maybe on one cylinder only. Like Bob said, completely eliminate the starter voltage issue or non-issue and let us know what you find out. It just doesn't make sense that the motor runs good and push starts easily and turns over easily with the plugs out so it has to be compression/valve train related somehow or the weak voltage to the starter, but you said it was cold weather related as well. Keep us informed to what you find. Good luck.

 

I would take a compression test of both cylinders and see where it comes in at. This may answer many questions here.

Bob is onto something here also. I had a 90 FXR that had a similar lazy cranking to it also. Don't rule out the battery cables themselves here either. You can upgrade them easily with welding cables with soldered ends on them to match the length of the origionals and they pass much more amps than stock. Check these out, they work well and have solved many cranking problems with big motors also .. HERE

Don't forget to ground the ignition coil and open the throttle wide when you do the compression test.

 

Still haven't had the chance to check that voltage drop at solenoid wire to starter. Will do asap!! One thing that I have noticed is that during these cranking over attempts, I am now seeing cylinder base gaskets are seeping oil. This is new as they have always been completely dry before now. Could my breather gear have gone out of wack or something? I know this can affect crankase pressure, but will this cause turning over problems?? As far as the valves/pushrods, etc. I'm getting ready to pull the cam cover, breather gear, cam & pushrods to take a look, right after I check this last voltage drop thing. Thanks for the input guys!!