Help...EVO Cutting out momentarily
Thread Starter
|
2nd Gear
Joined: Jun 2011
Posts: 6
Likes: 0
From: Hollister, Florida
Help...EVO Cutting out momentarily
Ive got a 88 FXSTC that is constantly cutting out as I go thru the gears or just maintaining speed, it sometimes responds to cycling the ign. switch (which is new again) but usually it is just a momentary pop. When it does this the tach also fall like it lost all power but bounces right back. Its almost like a primary ign. hot wire is brushing up against ground but I cant find anything bare or chafed. When I put a test light on the Ign posts it never even flickers so I think its downstream from the switch, do tachs or triggers or relays give problems like this? or is it just a connection that Im missing?
any advice will be appreciated.........OCG
P.S. if its relevant, the bike will idle all day without missing a lick!
posted this in the electrical/EFI forum too
1340-SE cam/clutch, SS super-E, mallory coil
any advice will be appreciated.........OCG
P.S. if its relevant, the bike will idle all day without missing a lick!
posted this in the electrical/EFI forum too
1340-SE cam/clutch, SS super-E, mallory coil
Outstanding HDF Member
Joined: Mar 2010
Posts: 2,877
Likes: 2
From: Hallsville, Tx.
Ive got a 88 FXSTC that is constantly cutting out as I go thru the gears or just maintaining speed, it sometimes responds to cycling the ign. switch (which is new again) but usually it is just a momentary pop. When it does this the tach also fall like it lost all power but bounces right back. Its almost like a primary ign. hot wire is brushing up against ground but I cant find anything bare or chafed. When I put a test light on the Ign posts it never even flickers so I think its downstream from the switch, do tachs or triggers or relays give problems like this? or is it just a connection that Im missing?
any advice will be appreciated.........OCG
P.S. if its relevant, the bike will idle all day without missing a lick!
posted this in the electrical/EFI forum too
1340-SE cam/clutch, SS super-E, mallory coil
any advice will be appreciated.........OCG
P.S. if its relevant, the bike will idle all day without missing a lick!
posted this in the electrical/EFI forum too
1340-SE cam/clutch, SS super-E, mallory coil
Thread Starter
|
2nd Gear
Joined: Jun 2011
Posts: 6
Likes: 0
From: Hollister, Florida
grounds good, just wire brushed and re-tighten and tried again, also checked the two what look like auto-reset breakers under the ign. swch. with test light and it never flickered when the power cuts out, pulling and twisting all visible wires and harnesses have no effect eithergetting ready to open up the tach and look for problems there and unhook it to try again....OCG
Outstanding HDF Member
Joined: Oct 2010
Posts: 2,706
Likes: 14
From: Near Frankenmuth, MI
Do you have your repair manual?
Check your cam sensor and wiring. These can wear and rub off insulation and fail intermittently. The wiring harness run through a small hole in the case in a hot spot of the engine. If original the cam sensor is open to the air, epoxy potted components. The new cam sensor is a solid state looking device.
It could also be a prelude to the ignition module failing. Might even be a failing ignition coil. Or the power supply lead to either one has a short. The circuit breaker just for ignition sometimes fails intermittently when heated up from current drain, often because the components it supplies are going bad or shorting.
Both issues will cause the tach to drop to zero.
Check your cam sensor and wiring. These can wear and rub off insulation and fail intermittently. The wiring harness run through a small hole in the case in a hot spot of the engine. If original the cam sensor is open to the air, epoxy potted components. The new cam sensor is a solid state looking device.
It could also be a prelude to the ignition module failing. Might even be a failing ignition coil. Or the power supply lead to either one has a short. The circuit breaker just for ignition sometimes fails intermittently when heated up from current drain, often because the components it supplies are going bad or shorting.
Both issues will cause the tach to drop to zero.
Last edited by JohnnyC; Jun 11, 2011 at 11:33 AM.
Seasoned HDF Member
Joined: Nov 2009
Posts: 15,705
Likes: 22,718
From: Farmington ,MS
Good place to start...put a toggle switch in it so you can run it for a while, to make sure that is the problem. Your post says you have a Mallory coil...they like Accel went through periods of putting out quality products and total crap...depending on who owned the name at the time. Do you still have the stock ignition? Lots of "cone" ignitions go out a little at a time giving the symptoms you describe.
Trending Topics
Road Warrior
Joined: Apr 2007
Posts: 1,952
Likes: 15
From: Senoia, Ga., by way of Miami, Fl..
grounds good, just wire brushed and re-tighten and tried again, also checked the two what look like auto-reset breakers under the ign. swch. with test light and it never flickered when the power cuts out, pulling and twisting all visible wires and harnesses have no effect eithergetting ready to open up the tach and look for problems there and unhook it to try again....OCG
When mine did the same thing, I finally found it by pulling on the sensor wires at the cam cone. The insulation was good and holding the broken wire together, most of the time.. Did you try tuging on those? do it while idling, sure sounds familliar..
HD Forum Stories
The Best of Harley-Davidson for Lifelong Riders
10 Worst Harley-Davidson Motorcycles Ever
Pouria Savadkouei
Killer Custom's Jail Break Is The Breakout That Refused to Blend In
Verdad Gallardo
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?
Verdad Gallardo
Harley-Davidson Reveals Super Cool Cafe Racer Concept
Verdad Gallardo
Engraved Rebellion: Inside Bundnerbike's Glam Rock II
Verdad Gallardo
10 Motorcycles You Should Never Buy
Joe Kucinski
10 Things Harley-Davidson Needs to Fix in 2026
Verdad Gallardo
Southpaw Super Glide: A Left-Hand-Drive 1979 Harley FXE Built to Fit the Rider
Verdad Gallardo
The Best and Worst Harley-Davidson Moves of 2025
Verdad Gallardo
Thread
Thread Starter
Forum
Replies
Last Post
Oldcraneguy
Ignition/Tuner/ECM/Fuel Injection
1
Jun 12, 2011 08:00 PM
