Hyosung GV250 slow electric start, bump-starts fine — starter clutch diagnosis
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Bike Model = : Gv250 2009
Hi everyone, I’m looking for a sanity check from people familiar with Hyosung engines before I open the left side of the motor.
The bike is a 2009 Hyosung Aquila GV250. The issue I’m chasing is a very slow electric start. When I press the starter button the engine cranks sluggishly and sounds labored, and if I hold the button too long the relay will buzz. However, the bike bump-starts easily and runs perfectly once started, with no misfires, stalling, or power issues.
I’ve gone through the electrical side very thoroughly. The battery is new and fully charged, and jumping the bike from a truck battery (engine off) made no difference at all. I tested the starter relay under load and measured about 0.1 V drop, so the relay appears healthy. Grounds were cleaned, tested, and even bypassed with jumper cables directly to the engine case with no improvement. I also powered the starter motor directly on the bike from the battery, bypassing the relay and wiring entirely, and it still cranked slowly.
With the starter removed, I bench-tested it and it spins very fast unloaded, which suggests the motor itself is good. The starter reduction gear spins freely by hand. I removed both spark plugs and rotated the engine via the rear wheel in gear; the engine turns smoothly with no signs of seizure or hydrolock. The spark plugs themselves look normal. Once the bike is bump-started, it runs exactly as it should. For what it’s worth, the pickup coil was replaced previously, but ignition clearly isn’t the issue since the bike runs fine when bump-started.
At this point, it seems like everything electrical and engine-side has been ruled out, and the problem only appears when the starter is trying to transmit torque to the crankshaft. Based on that, I’m strongly suspecting the starter clutch / sprag clutch behind the flywheel, possibly slipping or dragging under load.
Before I pull the flywheel, I wanted to ask those with more Hyosung experience: does this symptom set line up with starter clutch failure on the GV250? Is there anything else in the flywheel or starter drive system that could cause this behavior that I might be overlooking? And finally, are there any common tips or pitfalls I should know about before removing the flywheel (puller size, typical wear points, etc.)?
Thanks in advance for any insight! My first forum post..so glad I found this. I think I have the only GV250 in Hawaii haha.
Tobeychow
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I think I have the only GV250 in Hawaii haha.
Find hawaiians on social media and see if there is a biker community there and ask around, you will be surprised there could be one more. I am suspicious we have a member on here with a GD250 EXIV model but i could be wrong, if its true it could mean they have not posted in the forum for a long while.
In regards to your starter issue.
Replace the starter motor first, and crank on full throttle with a new relay. Test and report back ?
You can also carefully , extract the flywheel out of the bike and look at it , if it is under 10,000 miles old, I don’t expect issues with the flywheel system yet i hope not.
If in doubt, upload here what you see.
If you drain oil, replace it with Motul 7100 (very very good oil!) and get a fresh oil filter. Better to replace oil OFTEN as you like to keep the engine healthy as possible.
I change oil every 1,000 miles on my bikes. It is OCD / Crazy but i’d rather waste the oil than scream at engine replacements lol. The local recycle plant should take your old oils and they will re-use it for something else so you’re not killing the enviroment.
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I typically replace the oil/filter every 1000km or so (The bike is only 6000 km old). I’ll try that Motul 7100 and see how it is. Sometimes I can use my electric start for a few minutes after I’ve been riding for a while and the oil is hot. To be completely honest I’ve never opened the bike to that extent before, so I am a little nervous. I was going to order a flywheel puller, and I was trying to find the correct size gasket first before I do anything. Relay and starter are on the way so I will let you know how it goes next week!
Tobeychow
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I typically replace the oil/filter every 1000km or so (The bike is only 6000 km old). I’ll try that Motul 7100 and see how it is. Sometimes I can use my electric start for a few minutes after I’ve been riding for a while and the oil is hot. To be completely honest I’ve never opened the bike to that extent before, so I am a little nervous. I was going to order a flywheel puller, and I was trying to find the correct size gasket first before I do anything. Relay and starter are on the way so I will let you know how it goes next week!
Take your time, you got this!
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Unless you get a flywheel puller tool from the USA eBay (it should be there) then the other method (possibly) involves these 2 parts
Step 1 =
https://www.amazon.co.uk/FTVOGUE-Adjustable-Spanner-Flywheel-Motorcycle/dp/B09Y111WH6
That part can hold the drum tight so you can UNDO the nutStep 2 =
https://m.media-amazon.com/images/I/61yfS1yJ0wL._AC_UF894,1000_QL80_.jpgMeasure the diameter of your Hyosung flywheel center where the threads are with a venier caliper , as 250 will either be needing a 30mm or 35mm puller tool – i can’t remember myself correctly as i haven’t stripped a bike this winter
This should help you hopefully!
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Yes, because the woodruff key is needed to lock the rotor. You can feel how heavy it is don’t you!
So if it was missing or broken, you would also have “ROUGH” running as its not spinning properly which could eventually lead to a catastrophic failure.
Make sure the NUT is good otherwise get a new serrated nut that or metal-lock insert nut and use RED LOCTITE on the threads after replacing the woodruff key.
Any Hyosung 250 will have the same size or message local breakers for a much quicker acquisition of that part. Get a spare engine if you have to and its a good backup to have for the future 🙂
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Might have found my problem. Would a sheared off woodruff key cause this kind of starting problem?
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