FJRF011: Fast Starter Syndrome

Yamaha FJR Motorcycle Forum

Help Support Yamaha FJR Motorcycle Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Ignacio

Intramural Culture Warrior
Staff member
Joined
Jun 28, 2005
Messages
9,382
Reaction score
2,687
Location
Tri-Cities, WA
We've talked about a few times on this forum, but it's been fairly sporadic. But, after it's happened three times to me personally and observations on the forum--I think it's time to assign an issue number to this phenomenon and see if we can isolate the issue.

Issue Shorthand Name: "Fast Starter Syndrome"

Symptoms: (some or all)

  • Bike won't start
  • Bike has sat for a period of time (perhaps days or weeks)
  • Hit the starter and in the first 1/2 a second it just doesn't sound quite right.....and after a couple seconds not a hint the bike firing.
  • Starter seems a slightly higher pitch.
  • Starter seems to spin a little faster than usual.
  • You have to crank and crank it until it finally sputters and lights up.
Cause: Unknown

Hypothesis/Speculation of Cause:

  • This may be caused by marginally leaky fuel injectors allowing fuel from the pressurized fuel rail to slowly dribble into the combustion chambers. This could explain the hard starting unless WOT (flooded) and the faster than normal turn over (fuel washes oil off cylinder walls resulting in compression loss. (FredW)
  • Possible piston ring freezing into place or rusting. (Warchild & Ignacio)
  • Increased incidence with E-10 blends..possible rusting or gunking of pistons (Ignacio) or valves (
  • Winter blend vs. summer blend of fuel? (e.g.)A bike last used in September may not start well in cold January (Ignacio)
  • Temperature, humidity, and/or weather?
  • Letting bike sit after a short ride or "garage warm-up"? (gumba)
Resolution: Unknown at this time

  • Possible use of fuel additive like SeaFoam or other stabilizer
Workaround:

  • With a full battery and confirmed fuel in the tank press the starter and DO NOT LET GO. Alternate slowly between no throttle and full throttle....or perhaps no throttle to 1/3 throttle.
  • Engine will eventually light--probaly cough and sputter. Don't let up on the starter. Recycle the throttle again noting if some position seems a sweet spot.
  • If the battery goes dead...recharge and try again. Or consider a high amp charger.
Other Observations:

  • Ignacio has had it happen 3 times over the life of his '05 with 135,000 miles. The last time he noted that he could smell fuel from the exhaust and had both fuel and spark the first time it happened removing the plugs.
  • Ignacio hasn't found a temperature correlation. First and second time were in the 60-80 degree range and third time was in the 40's.
  • Ignacio has found it happens more often on season shoulders (e.g. Fall when it cools down and/or Spring when it warms up...possibly exacerbated by change in seasonal fuel formulations)

ADMIN NOTE: Subsequent posts may merged into the first thread and removed to keep the thread clean and on point. Constructive criticism and observations encouraged.

 
Last edited by a moderator:
3 whole times in 135,000 miles? Wow. That must be a record Chicken Little.

Hugs & Kisses, babe.

:fuck:

 
I'm not sure how good an idea the "DO NOT LET GO" is, as mongo current goes through the starter windings, and it's really really hard to get to it when it needs replacing.

I understand the reasoning, though.

Loss of compression sounds like a reasonable hypothesis as to the cause, with the symptom being faster cranking, but rings aren't the only place compression could be lost. Valves not seating seems a possibility, but how that would fix itself after sputtering for a while is beyond my simple understanding. Loose in its guide so it doesn't seat, sounds really bad. Sticking open, sounds really bad, too, and really bad if it's sticking far enough out to meet a piston. Rings, on the other hand, would recover with some oil pressure, but it shouldn't take that long, I wouldn't think (again considering my limited understanding of what actually makes these things work.)

 
Had the same syndrome after a couple of weeks away from bike, an 06 with 30,000 miles (hey, I bought it used with 1700 miles). Usually run a bit of Startron in tank, but not frequently. I definitely felt I had lost compression as I had the faster starter and engine spin with no attempts to fire the mixture. Even though I felt it was for pure motherhood, since I had put new irridium plugs in less than a 1000 miles prior, I decided to pull them and look at them. Thought maybe I had left one loose. They were tight, but they were dark/ dry carboned. I cleaned them, closed the plug gap to .028 and re installed. Bike fired by the second or third spin, but emitted some rich exhaust. Susequent ride, all was well, and since then.

I have no idea what happened really, but I speculate that something is causing the mixture to go rich. I believe this is fouling the plugs, and may even be placing enough deposit on the valves to cause low compression on subsequent restart.

I have a mechanic aquaintenance who says he has seen a hard carbon deposit on valves running on E10, even if the unit has low mileage. It is his theory that the deposit goes on wet, runs to the vavle face on sitting, and bakes to a very hard surface that is very difficult to remove. On the few units encountered to date (none FJR's), he has simply replaced the valves.

I plan to use more Seafoam and/ or Startron and see what happens. And of course await the day when the science of all this Ethanol insanity dawns upon my congressmen --- NOT!!

 
I've had it happen twice on my bike. WFO throttle seemed to remedy the situation.

 
Only happened once to me in 70K miles. Incident was a spring startup maybe 40K miles ago. WOT ultimately fixed it but required a jump from a car battery as initial bike only battery power was exhausted before she sputtered to life.

 
It happened to me three times on my first bike...not all in the same year. Each time after a layoff...once in the summer after a heat spell where I stayed off the bike and family vacation, once in a rainy fall before Hooterville, and once at the beginning of the riding season.

Charged up the battery, came back to it the next day WFO (wide fooking open), once pulled the plugs before Hooterville.

Haven't had it happen on my second FJR yet. We'll see come this spring...

 
I've experienced this phenomenon twice in 90k miles. Both times I had come home from a multi-day ride and parked the FJR for a week or more. The first time I don't remember the weather, but the second time it happened I had been riding in heavy rain all day and put in in the garage wet.

 
Why do I get the impression that this can all be traced back to garage warm-ups and short-hops?

 
Hypothesis: This may be caused by marginally leaky fuel injectors allowing fuel from the pressurized fuel rail to slowly dribble into the combustion chambers. This could explain the hard starting unless WOT (flooded) and the faster than normal turn over (fuel washes oil off cylinder walls resulting in compression loss.

On my Mazda RX-7 this was a well known symptom that would occur if one started the car and didn't allow it to warm up enough. The amount of fuel from just a single cold start, if left on the rotor walls, was enough to cause loss of compression.

 
Last edited by a moderator:
Fred, I do believe that was what was speculated about my bike (fuel washing walls of combustion chambers causing loss of compression). First time it happened, I didn't get her fired up right away. I brought bike to dealer a few days later, who said my starter was going bad. They told me that another known battery was tried in case mine sucked & did not make any difference on the "really slowwww engine turn".

I say "funny, it was just spinning it's ass off the other day".

I went & gathered her up sweating what the problem was since they didn't figure it out.

Further investigtion was done by S76 (Bob), who checked my valve clearances since I thought I may of bent valves by the way it just turned normally for a revolution & then spun. He said valves didn't appear bent. He squirted a bit of, I think it was silicone into each cylinder, put the plugs back in & did WFO throttle & bike sputtered & started blowing black smoke all over my friend, Jay who was sitting down in back of the bike.

Speculation was that flooding caused oil to be rinsed off of chamber walls... hence loss of compression. Once the gas dissipated, there was no lubrication for the pistons... hence the slowwww turning bike experienced by dealer.

I'm no mechanic by a hugely long stretch... but think this is what I was told.

The second time it happened I was aware of the issue & I was more adamant about getting her started.

 
Last edited by a moderator:
Hypothesis: This may be caused by marginally leaky fuel injectors allowing fuel from the pressurized fuel rail to slowly dribble into the combustion chambers. This could explain the hard starting unless WOT (flooded) and the faster than normal turn over (fuel washes oil off cylinder walls resulting in compression loss.
That's a good hypothesis....and makes me glad I started this thread up. I'll add it to the top and appreciate the wider feedback than I would have guessed. I think this happens a bit more than any of us might have thought.

I'm also contemplating a poll, but haven't done one yet on this thread because I want a bit more discussion first....but I can see one shaping up. ;)

Thanks FJR Forum! Once again the depth of knowledge in this place is the reason this forum rocks!

Ig

 
An obvious and simple (and fun) solution: don't let the bike sit around gathering dust ;)

Iggy, feel free to zap this post.

 
Why do I get the impression that this can all be traced back to garage warm-ups and short-hops?
Very valid point, especially with E10. I can't recall where I saw it, but someone posted some pictures of some pretty gummed up valve stems, and someone else had posted up pictures of the engine side of the TB butterflies. Don't know if it was here or not. But E10 is apparently a big problem in marine and lawn equipment engines. Not so much up here where I am, but down thar in the corn belt..... and I don't want to think about E15.

So, maybe a valve or two is sticking upon first spin-over? I guess one of the only ways we're gonna know is if someone feels like doing a teardown for a look-see. Meanwhile, let's keep banging heads to see if it's something else.

 
A possible/likely answer is a leaky check valve (back flow prevention) at the fuel pump. If the check valve allows the fuel rail pressure to drop over time the brief fuel pump operation at key 'on' may not be long enough to fully pressurize the fuel rail. If the fuel pressure is low the fuel may not atomize properly and/or may not be emitted in proper quantity at start-up. If this happens more of the fuel ends up coating the cylinder wall and flooding can occur.

It's been suggested before that one should cycle the fuel pump a few times before cranking the engine if the bike has been sitting unused for a long time. This ensures that the fuel rail is pressurized properly before cranking.

 
If valves were sticking open, why would holding the throttle open and cranking for a long time make it start?
You're right it probably shouldn't... By some of the descriptions it sounded like one or two cylinders were firing, so holding open the throttle might help get those going a bit stronger, then as the valves cycle and loosen up......... maybe?? Same deal if it was water...

 
Well since my condition may or may not be related to this, today after putting in 1 oz per gallon of Seafoam, doing several wheelies to make sure the SeaFoam was properly mixed in the gas, today I had no Problems with starting either Cold or Hot.

Should this be related to Carbon Deposits, I would try the Yamaha Ring Free to see if this would help, since it is more focused on the Ring/Deposit issues.

Hopefully I won't need it and think the wheelies broke some things free.

 
If valves were sticking open, why would holding the throttle open and cranking for a long time make it start?
Two different issues being discussed here.

Wide-open throttle starts a flooded engine, said flooding caused by starting and shutting off cold. Doesn't have to sit very long for the next start effort to be a non-firing bike.

What Iggy posted about is a non-start from what is apparently a lack of compression (fast spinning starter) which may lead to flooding as it's cranked. His fired up finally as he cycled from closed to quarter or third throttle. Only happens after sitting for a while, with conditions at the previous stop (warm or cold) pretty much irrelevant.

This is different from the flooded condition caused by shuttong off cold in most Gen-IIs.

 
Top