Electric starter will not start cold engine | GTAMotorcycle.com

Electric starter will not start cold engine

janosdre

Well-known member
My son has a 2005 Yamaha TT R 90, it's a small bike with a four stroke engine. The electric starter will not start the engine when it is cold. It will start the engine after it's been running for a while and it has warmed up. I can started with Kickstarter easily. The electric starter does turn the engine. It has the power to start the engine multiple times so I'm sure it's not a battery issue. It has fresh oil and I just change the spark plugs. The carburetor was also recently cleaned.
Once it gets started the engine runs great.

Has anyone come across this issue before? Does anyone know what could be the issue here and how to fix it?


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Assuming it is a 12 volt system ... Connect the bike's battery to a big battery (e.g. a car battery with the car not running) with booster cables and then try it.

The battery in the bike might have enough storage capacity to start the (warm) engine multiple times, but it might not have enough cold cranking amps to start the cold engine. If it cranks and starts OK when in parallel with a big battery then possibly the battery has seen better days, or the charging system isn't fully charging it.

Check charging voltage with engine running (and the above booster cables disconnected). Should be 14.something. If it's less than 13.5 volts the alternator/voltage regulator etc is not fully charging the battery.

If it's cranking weakly no matter what, check for corroded battery terminals, corroded or loose ground strap, corroded or loose connections at the starter relay.
 
Thx, I'll give it a try.


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Just to clarify, does it crank like crazy but just won't fire? Or does it crank slow?
 
Valve adjustment possibly. If exhaust valve is too tight especially will make it hard to start
 
Hi. Thanks for all the good ideas and help. I was derailed by some other work on this bike a my bike. This bike had some issues with the Kickstarter too. The friction plates in the main clutch got glazed and the Kickstarter wouldn't turn the engine. It was almost running free when I kicked it. I rubbed the friction plates with a wire brush, so it starts, but I will need to replace the friction plates.

Yes, the choke and fuel valves are on.

I made a video of this issue. I will post it to YouTube and share the link.

Boosting it is a bit of a problem. The connectors are so tiny, I'm not even sure it can be boosted with a larger battery.

I hope the video will help.


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Hi

Here is the link to the YouTube video I made about this issue.

https://youtu.be/cP4yhffyQSQ

Also, a bit of history might help.
I bought this last year from a grown man who used it as a pit bike. He was a big guy. The bike already had this issue when I bought it.

After I got the bike home, I did some maintenance on it immediately. Cleaned the carbs, changed the oil, replaced the spark plugs and I replaced some other worn parts that should not affect the engine.


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Valve adjustment possibly. If exhaust valve is too tight especially will make it hard to start

Hi Taxinan62,

Which, valve are you talking about? The one in the engine on top of the cylinder or do these bikes have a valve in the exhaust system?


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It sounds to me to be cranking quite slowly on the electric start, I would definitely try the booster cable test and I think you will find it suddenly starts dramatically better - A lot of small engines, especially ones that have had rough lives & might be low on compression do need a fairly high cranking speed in order to fire. In addition,

The fact that the battery voltage is sagging during cranking can also exacerbate the issue on some bikes.

Yes, getting booster cables on some of the small terminals on motorcycles can be a pain, however there are usually several different options – either at the battery itself directly or the starter relay. Typically the battery itself is easiest.
 
It sounds to me to be cranking quite slowly on the electric start, I would definitely try the booster cable test and I think you will find it suddenly starts dramatically better - A lot of small engines, especially ones that have had rough lives & might be low on compression do need a fairly high cranking speed in order to fire. In addition,

The fact that the battery voltage is sagging during cranking can also exacerbate the issue on some bikes.

Yes, getting booster cables on some of the small terminals on motorcycles can be a pain, however there are usually several different options – either at the battery itself directly or the starter relay. Typically the battery itself is easiest.

Thanks. You beat me with your response. I will try to get my bike's battery on it somehow. Maybe directly to the starter as your suggesting.

I also put the battery on the charger again. It was drained now from all the trying.


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Cool. Thanks. I will have a look at it.


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Hi PrivatePilot,

The crank seems normal, not slow.

normal cranking can still mean too much juice say ..to a worn out starter (could just be dirty brushes?) and or other wiring issues = a weak spark

weak or strong cranking, +1 including starter connections
If it's cranking weakly no matter what, check for corroded battery terminals, corroded or loose ground strap, corroded or loose connections at the starter relay.
 
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Hi. Thanks for all the good ideas and help. I was derailed by some other work on this bike a my bike. This bike had some issues with the Kickstarter too. The friction plates in the main clutch got glazed and the Kickstarter wouldn't turn the engine. It was almost running free when I kicked it. I rubbed the friction plates with a wire brush, so it starts, but I will need to replace the friction plates.

fix asap pronto, otherwise good bet wont go far when the engine runs
 
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Hi. So here's where I am with this. I checked the valves and their good. Just to cover all my basis, I checked the spark plug. It turns out that most of the time there's no spark when I use the electric starter. The sparks are good when using the Kickstarter.

Any ideas?


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You keep ignoring the suggestions to try a boost...

From what I can gather the TTR90 uses a CDI based ignition system which typically requires a battery (at proper voltage) to function properly.

So, when you try to start with the electric start the battery voltage sags, the CDI doesn't function properly, and you get the exact symptom you explain - no spark, weak spark, occasional no spark.

When you use the kickstart, no battery drag from the electric starter, voltage doesn't sag, CDI works, engine starts.

So yes... try a boost and report back...like I said before, I think you'll find it magically starts like a dream with PROPER voltage at the battery under cranking.

I'd suggest just going and buying a new battery however that constitutes "throwing parts at it" which is an expensive diagnostic method. Testing it via the boost method first is a simple and cheap method to basically confirm the battery is weak.
 
You keep ignoring the suggestions to try a boost...

From what I can gather the TTR90 uses a CDI based ignition system which typically requires a battery (at proper voltage) to function properly.

So, when you try to start with the electric start the battery voltage sags, the CDI doesn't function properly, and you get the exact symptom you explain - no spark, weak spark, occasional no spark.

When you use the kickstart, no battery drag from the electric starter, voltage doesn't sag, CDI works, engine starts.

So yes... try a boost and report back...like I said before, I think you'll find it magically starts like a dream with PROPER voltage at the battery under cranking.

I'd suggest just going and buying a new battery however that constitutes "throwing parts at it" which is an expensive diagnostic method. Testing it via the boost method first is a simple and cheap method to basically confirm the battery is weak.

I'm going to have to figure out a way to do the. Thanks PrivatePilot.


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My Husaberg is hard to start cold with the electric start in fact KTM call it a restarter and suggests the electric start only be used on a warm engine. Maybe it is just the nature of the beast if a boost doesn't help you may have to kick start it when cold.

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