KymcoForum.com
General => General Discussion => Topic started by: hypophthalmus on July 13, 2017, 04:38:58 PM
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As discussed in another thread, my People 250's engine self-destructed at just over 19,000km (12,000ish miles). The timing got off somehow, and the piston collided with the valves, leaving the crankcase full of tiny metal fragments.
It's bothering me that I don't understand what happened. I maintained it religiously, and it seemed to be working great just prior.
It's making me not trust Kymco engines in general, to the point that if I do find a replacement engine, I might decide to sell it. Maybe they're all at the edge of mysterious and catastrophic failure?
On the other hand they're held in generally high regard and the forum isn't full of people with this problem.
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Your disaster has shown the rest of us to get familiar with the timing chain tensioner, how it works, how to set/adjust it and how often. That is no consulation to you and the work and expense to get your ride back but is of great value to all that you shared and were very quick to remove and tear-down your engine. I think this is an isolated incident since there are some really high mileage contributors to this forum. I bet De dee has not tensioned the timing chain on his 50000 mile DT300i yet!
Karl
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My 2006 People 250 has about 24K KM/15K miles with absolutely no engine issues. I own 6 other Kymcos with considerably less mileage, but also no engine issues. Based on my positive experiences and the experiences of other Kymco owners, I think your engine problem is an isolated incident. Then again, it wouldn't hurt for all of us to keep an eye on the timing chain tensioner.
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Unfortunately failures happen. Kymco is known for its high quality and I believe they perform rigorous tests to ensure reliable products. I feel bad for you cause you did nothing wrong to deserve this. Hopefully you can find a replacement engine and be back on the road. I would not give up on Kymco. They have a proven track record for reliability. Even competitors rely on Kymco's to manufacturer components used in their product offers. Those competitors are the most reliable PTW manufacturers on the planet. They are not about to have just any manufacturer make components for them.
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Timing chain tensioners are totally maintanance free - normally. There is nothing you can service or adjust. They should work reliably for the whole life of the engine.
Hypo just had bad luck with his tensioner. Somehow the spring in this tensioner must have suffered an early fatigue or cracked (material defect) and caused the chain to leap over a tooth or two on the sprocket of the camshaft due to tension deficit.
That´s why I do not baby my engines too much nor treat them religiously. Right from the start. Because only then a weak part can and most likely will be detected soon and preferably within the warranty period. :) ;)
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I was just about to say this about the tensioners. It sounds like on modern bikes, they're almost always automatic. They're pushed out by spring tension, but they can't retract like zip ties.
As far as I can tell, mine is normal in the regard. I suppose it's possible that the spring is weak (I don't have another one to compare it to) or it got stuck somehow.
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I do hope my posts helped someone though.
I did get some value out of it as well: I learned a lot about engines. And discovered that these engines are incredibly pleasant and easy to work on. It took my about three stress-free hours to get the head off, versus at least 3 very stressful days on my van.
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I don't know what kind of tensioner is on your bike but if you are interested in reading here's a post about my '03 Suzuki Burgman 650 which had a engine rattle clack noise at just off idle. The timing tensioner turned out to be the issue of a poor design/manufacture and how I resolved the problem through a modification. http://burgmanusa.com/forums/15-burgman-650/53149-engine-rattle-idle.html#post526929 (http://burgmanusa.com/forums/15-burgman-650/53149-engine-rattle-idle.html#post526929)
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You inspired me to open my tensioner up.
The design is different. Basically, a very long strip of metal acts as a spring, turning a threaded rod down a threaded hole. It can't be pushed straight back because of the threads.
It's well oiled, and mine seems to be working smoothly with the threads in good condition. As hard as I tried to push and jiggle it, I couldn't get it to slip.
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Sounds like the Honda tensioner. 'Magine that!
Karl
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I've been considering my options in case I do need to part out my bike. Although I'm definitely getting way ahead of myself since it's going to be a long time before I can actually afford anything...
In short, I need something that can reliably take 300ish mile round trips loaded with camping supplies. Windy mountain roads (occasionally rough gravel ones full of pot holes.) and fast (80mph) highways.
The 300cc Kymcos seem very compelling on paper. Do they really put out 29.5hp? That sounds incredible for it's size and weight.
Otherwise, the most compelling scooter is the Yamaha Majesty. Only slightly wore gas mile and larger. In terms of power, still favorable to what I had and I wouldn't be taxing the motor as much. Parts availability would be better (there's a only a Yamaha dealer I think where I'm trying to move to). I briefly saw one on Craigslist where I'm trying to move to for $500... I wish I hadn't.
Lastly, there's the Virago / VStar 250. I've always thought them to be very nice looking. Now I'm realizing that technically they have some compelling advantages. There'd be no worries about cooling failure since they're air cooled. It puts out a good deal of power while being light weight. Apparently fuel efficiencies in the 70's and 80's mpg isn't uncommon. And supposedly v twin engines sound nice (I'm a sucker for nice sounding things).
The obvious problem (and the reason I never went with it in the past) is the complete lack of storage. But maybe with enough bags it wouldn't be so bad? Also, I'd have to learn how to true and tension spoked wheels which has always sounded intimidating.
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First option that comes to mind in your price range, after reading your 'needs' list is a 6 to 10 year old Corolla.
Others will disagree, but I think you're asking a lot of a 300 cc scooter.
Stig
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First and foremost, it needs to have two wheels for a number of reasons. The Corollas don't perform well in that configuration, and are out of my price range anyways.
Is there a reason you're suggesting a car instead of a more capable bike?
The Majesty is actually 400cc. But the 300cc Kymcos put out almost as much power, and have a better power to weight ratio.
I'm open to larger engines if it's necessary for reliability and longevity. And there are a lot of tempting Silverwings around that can be had for not much money, if only the gas mileage weren't relatively terrible. Although I'd like to do as much as possible with as little as possible. I've never had a complaint with how the People 250 performed on those roads.
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I owned a 2013 Yamaha Majesty for all of one month until I had an accident caused by carelessness and inattentivness that totaled it and hurt me. I LOVED it. I had put less than 100 miles of 3,000 miles on it in 28 days. I bought it as a previously unsold unit with only 1/10 mile on it. But from what I've read on the Yamaha forum, they are nearly indestructible provided you change the air filters religiously. They get dirty easy and are fairly difficult to change. So many people neglect them. But the maintenance is low. And I've seen a few owners who report 70, 80,90 thousand semi trouble free miles. The biggest advantage I see vs the Downtown is legroom. The seat is adjustable. The thing has a HUGE amount of space under the seat. It held nearly as much as my Xciting 250 which had a top box on it. They did have fuel pump problems but I believe most were repaired under recall. It doesn't have an oil light nor does it have a power point. But I added my own power point. And the battery is fairly difficult to access. From what I've read, off the line power is low (1-20 mph) . But it was more than enough for me. It has a top speed of around 95 mph gps verified. I rode it to work 3-5 day/week 50 miles one way. I averaged around 50-55 mpg at highway speeds (60-65 mph) . It does NOT have abs. And I believe that it has a single disk front and rear. But it always stopped very well and under control (provided I actually applied the brakes. Lol) . I sat on a Honda Forza. It had somewhat less legroom.
Maybe, I'm just nostalgic because it was taken from me. But I loved it.
But if you do get a Majesty, you'll still want to remain in contact with THIS group of people. They are a lot less grumpy that those on the Majesty forum.
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One thing Forbes forgot to mention: a Majesty, in the flesh, is a gorgeous looking scooter!
(also, recent top 10 article rated Yamaha as #1 in quality)
Stig
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Ok first things first. Kymco motors are not running at the bitter edge of disaster.
Matter of fact the P250 is known for having miles piled on, ive seen them with 30,000 miles on them. The rap was they were a bit slow but sturdy.
Yep the 300s put out just under 30hp. They have one of the best weight to HP ratios of any 300 scoot.
That said with my 130lb butt on board 80mph/gps on the slab is doable but that's the upper end. I've run 1000 miles on I95 and lived to tell about it.
You need more than 300ccs.
AMAC
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AMAC .....you're a pistol!
".....bitter edge of disaster." Great stuff! Always a treat to read your posts.
Spot on ....and how do you spell erudite?
Stig
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AMAC .....you're a pistol!
".....bitter edge of disaster." Great stuff! Always a treat to read your posts.
Spot on ....and how do you spell erudite?
Stig
I cant spell, or type.
Everything voice rec. lazy crip !
AMAC
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I cant spell, or type.
Everything voice rec. lazy crip !
AMAC
[/quote]
A lazy guy doesn't ride a scooter from NJ to St Augustine, Florida!
That is hard work.
Stig
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Interesting that the 300 Kymcos are slower even with a better power/weight ratio. I guess I don't really understand the physics of it (drag being a bigger obstacle than weight, gearing, something else?). It sounds then like the Majesty wouldn't be pushed as far to its limits in terms of speed. I'm not sure how hills fits into this though.
People 250's may be sturdy, but for comparison there are bikes with reports of 200,000+ miles. They tend to be 650 and larger though. I don't know if that's because people don't put that kind of mileage on smaller bikes or if the smaller ones don't survive that long. If you do need a large enough engine for that kind of lifespan, I also don't know where that line is.
That's a compelling recommendation for the Majesty, and definitely respectable engine life reports. The only part that gives me pause is the air filters, since I intend to go on some gravel/dirt roads. It might be bad if they get dirty easily under normal circumstances.
Speaking of ABS, does anyone know if you typically need some sort of expensive computer controller to activate the ABS pumps on scooters when you're changing the brake fluid?
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Interesting that the 300 Kymcos are slower even with a better power/weight ratio. I guess I don't really understand the physics of it (drag being a bigger obstacle than weight, gearing, something else?). It sounds then like the Majesty wouldn't be pushed as far to its limits in terms of speed. I'm not sure how hills fits into this though.
People 250's may be sturdy, but for comparison there are bikes with reports of 200,000+ miles. They tend to be 650 and larger though. I don't know if that's because people don't put that kind of mileage on smaller bikes or if the smaller ones don't survive that long. If you do need a large enough engine for that kind of lifespan, I also don't know where that line is.
That's a compelling recommendation for the Majesty, and definitely respectable engine life reports. The only part that gives me pause is the air filters, since I intend to go on some gravel/dirt roads. It might be bad if they get dirty easily under normal circumstances.
Speaking of ABS, does anyone know if you typically need some sort of expensive computer controller to activate the ABS pumps on scooters when you're changing the brake fluid?
Not sure where the kymco 300s are s lower.
Slower than what? Other scoots or cycles.
Can't compare scooters to cycles.
AMAC
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I meant compared to the Majesty. The Majesty has an extra pound or two (roughly estimating the wet weight of the Downtown) per HP.
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Looking/thinking into the Silverwing more, the difference between that and the Majesty in terms of gas mileage isn't *that* big of a difference. Apparently if it's 2008 or later, it's actually the same, due to the addition of an O2 sensor.
It seems like the consensus is that the Silverwings should last into the hundreds of thousands of miles too. And while I don't strictly need it, I'm sure the extra speed would be nice.
Maybe it'll just come down to what's available at the time.
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Here's another possibility for your failure. Worn out timing chain guides. While it would be unusual for the guides to be worn enough to jump teeth with only 12,000 miles, it's not out the question. Here's why. The links on a timing chain and most all chains, for that matter, are stamped. If you pull the chain out of your broken motor and look at the edges of the links, the part that rides on the guides, with a magnifying glass, you will see what looks like a metal file. This is the results of a badly worn stamp press. Whenever I replace a timing chain, in any kind of engine, I first take it to the polishing wheels and polish the side that will contact the guides until it looks like chrome. Harley Davidson (sorry Tom to mention that dreaded name and I use it here only for illustration) has had a world of problems with their cam chain tensioners on their big twins for this very reason, resulting in class action. Perhaps your engine was built just before they replaced the stamp jigs. Anyways, I'm sorry your engine broke and I know Kymco makes quality bikes.
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Unfortunately I can't be sure of the condition of the guides, since I got one stuck/pressed between the head and the cylinder block. Evidently there's no way for the head to clear the frame without removing all of the studs, and I hadn't noticed the guide had gotten between the two went I went to push the head back on.
I don't see any obvious signs of wear from the chain. The top guide is bent out of shaped and a bit roughed up at a corner... but that could have easily been me. The bottom guide looks fine, as far as I can tell..
I'll definitely keep in mind that I should polish any new cam chains I install though.
When the chain was installed, I could move a link just a tiny bit up from the sprocket. Should that be possible if it's correctly tensioned?
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The simple answer is no you should not be able to move the chain on the sprocket if it is properly tensioned. However all chains have an acceptable deflection limit between sprockets. Can you tell if the chain is broken. The guides probably weren't the cause for the lost timing. The idea of polishing the links is a good practice regardless. You wouldn't notice how rough they were with out very close inspection. Those guides and/or tensioner shoes are usually made of nylon, nylatron or fiber and they don't last long if the link edges are scared up.
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The amount I could move it was very very little, but still there. So I guess the tension was in fact low?
The chain is still in tact.
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One thing Forbes forgot to mention: a Majesty, in the flesh, is a gorgeous looking scooter!
(also, recent top 10 article rated Yamaha as #1 in quality)
Stig
Yes, it was a beautiful scooter. I used to get compliments all the time.
Oh. I just LOVED the parking brake. I could park it ANYWHERE without fearing that it would roll off its stand.
Sent from my iPad using Tapatalk
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I'd like to put in a plug for the SW. First off, I bought my 2003 ABS for 1900 with 39k. I had no misgiving about buying a high mileage SW but in truth is not high mileage for this scooter. It can easily go over 100k and some have gotten over 200k. I expect this will be my last Maxiscooter and will out last me. I've owned now for 3 years and have had "0" issues. It truly is the Swiss Army knife of Maxiscooters. I wouldn't hesitate riding mine cross country. It's wonderful for 2up also and is smooth as silk even at 100mph. Perhaps if there was any issue it might be the weight for some as it tops out at 550. Having moved down from a Goldwing at #950 pounds, it feels like a flyweight to me. I get about 50mpg which I find acceptable as my Goldwing was about 30 and my present BW 250 gets about 60.
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A parking brake would have helped me recently. After I got my People 250 up into the Uhaul truck, I put it on the side stand so I could rest. It almost slid out.
The last time I was looking for a bike, I was reluctant to consider bikes with significant mileage. But at this point, I'm starting to see that kind of mileage as someone testing out the scooter for me to make sure it's mechanically sound.
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The last time I was looking for a bike, I was reluctant to consider bikes with significant mileage. But at this point, I'm starting to see that kind of mileage as someone testing out the scooter for me to make sure it's mechanically sound.
Depends on the bike and care it's had. Bought an older 85 Honda GL 1200 once with 100k and didn't bat an eye. Some bikes are historically noted for high mileage and are good buys like the SW.
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Yelp Dano I really miss that parking brake. The DT would 100% perfect if they had equipped it with a PB. Shore wish I'd kept my last SW. Oh well