KymcoForum.com
Scooters - 125 to 300 => Downtown 300 => Topic started by: mousejunks on September 30, 2023, 01:03:03 PM
-
Downtown 350 with 30,000km.
Riding on the street in heavy traffic. Moved off from stationary and the bike started shaking/stumbling on acceleration to 40km/h. Idle speed dropped to 1400 rpm. Above 40km/h, no issues with acceleration or vibration as if it was normal.
The other issue that suddenly appeared was the bike would move forward on idle. Pulled over and noticed that the rear wheel would spin fast and could only be stopped by holding the brake.
I strongly suspect that one of the clutch pad springs broke and the pad is now engaging with the clutch bell, causing the transmission to be engaged with the rear wheel all the time.
-
Mouse yes, I think you're on the right track.
Take off CVT housing and have a look at your clutch.
NOT very likely but possible, a part of your belt got seperated and stucks somewhere.
All symptoms hint towards this clutch.
-
yes, I think you both nailed it...a rear wheel always moving means the clutch is somehow always engaged. Tear it apart and see what you find! (and then be sure to let us know!)
-
But Mouse, couldn't this scoot simply be afraid and started shakin'?😉
-
But Mouse, couldn't this scoot simply be afraid and started shakin'?😉
Yes it was afraid to go to work. ;)
-
Just an update - this is what is looked and sounded like before taking it to the mechanic. Why mechanic? It would be the first trip in the scooter's lifetime and it'll be good to know what they want they plan to do with it.
https://youtu.be/syxdOiRECzU (https://youtu.be/syxdOiRECzU)
-
Mouse, sounds like belt and/or clutch to me. Maybe front pulley/rollers too...
Would be interesting what they find on there.
.
-
I had similar issue when I put chinese 15g 20x12 sliders. Clutch was engaging on idle rpm's. When I swapped sliders for 15 g 20x12 rollers problem was gone :o
-
Interesting what Ericson says.
Had the same issue with original TechPülley "gliders", after I polished the CVTs ramps and the pressure plate it ran normal again
-
My $ on flipped Dr P's....(which aren't in there)...so more $ on the clutch. Spring broke or pad came loose?
Easy to spot and fix once belt cover removed.
Stig
-
I had similar issue when I put chinese 15g 20x12 sliders. Clutch was engaging on idle rpm's. When I swapped sliders for 15 g 20x12 rollers problem was gone :o
All stock rollers for me because they work. Never used sliders for this bike.
-
Update:
Mechanic says a roller shattered and caused lots of damage to the CVT. According to them, looks like most of the CVT parts will have to be replaced, including the belt, clutch and pulleys as they are all damaged. I'm very shocked this has happened.
I'm thinking if this is done it will be $$$, but I won't have to do any major CVT maintenance for a long time - at least for the next 20,000km. I normally do maintenance myself this is not maintenance but a significant repair job.
Thoughts?
-
Not sure what the replacement interval for roller weights is on your scooter. At 30,000km, were they ever replaced or at least inspected?
That said, never heard of a CVT weight shattering!
Stig
-
Not sure what the replacement interval for roller weights is on your scooter. At 30,000km, were they ever replaced or at least inspected?
That said, never heard of a CVT weight shattering!
Stig
A roller shattering is shocking news and unheard of. Will have to go to the mechanic to confirm.
Yes they were replaced at 20,000km, along with the drive belt. There is no interval in the manual, only inspection and replace if necessary, which they were.
-
Sorry to read that, Mouse!
Since a CVT consists of a lot of parts, I would not take the mechanics statement as granted.
Front pulleys? What happened to them? Clutch, completely disintegrated? Belt, okay, should be.
Demand documentation of all this .
All complete CVT inclusive clutch and belt should not be more than €500,- for your scoot, plus two hours of labour.
Do they charge you for diagnostics too?
-
Sorry to read that, Mouse!
Since a CVT consists of a lot of parts, I would not take the mechanics statement as granted.
Front pulleys? What happened to them? Clutch, completely disintegrated? Belt, okay, should be.
Demand documentation of all this .
All complete CVT inclusive clutch and belt should not be more than €500,- for your scoot, plus two hours of labour.
Do they charge you for diagnostics too?
They said a roller broke open which caused much damage so the pulleys, belt and clutch have to be replaced. I didn't get any more information than that so I will ask for information tomorrow.
Diagnostics will be included in the final price, no idea about the final value, but it will be much higher than 500 EUR.
-
At those prices for all those parts on a 7 yr old 350 scooter - I'd pay them for their one hour of inspection, then I'd bring it home.
I'd do my own parts replacement ....as needed after inspecting.
A shattered weight might not have grenaded the entire CVT!....not every single part!?
But it is your dime, of course.
Good luck!
Stig
-
What Stig said....
Firstly there is very little opportunity for roller pieces to escape their area to the outside, as I recall. May be as dust but that's ir. A broken clutch shoe spring definitely but not a whole clutch. Even spring pieces won't go that far unless very small, again, not spring failure mode.
-
Mouse, I personally have an aversion against such general judgments done by dealership.
CVT, clutch and belt replacement is not really rocketscience, if you obey certain things and have some tools and handiness at ready.
Some things to repair is out of laymans reach, but this can be done by you.
-
What Stig said....
Firstly there is very little opportunity for roller pieces to escape their area to the outside, as I recall. May be as dust but that's ir. A broken clutch shoe spring definitely but not a whole clutch. Even spring pieces won't go that far unless very small, again, not spring failure mode.
Mouse, I personally have an aversion against such general judgments done by dealership.
CVT, clutch and belt replacement is not really rocketscience, if you obey certain things and have some tools and handiness at ready.
Some things to repair is out of laymans reach, but this can be done by you.
I would mostly agree. I am relying on the mechanic's opinion at this point, still have no idea what the physical damage actually looks like.
Will update you all soon.
-
Update:
Mechanic wants $3000 just for the 2x front pulleys, ramp plate 2x rear pulleys, sliders, rollers and belt plus 5 hours total for labor. Not including the clutch shoes or springs which is surprisingly undamaged.
Ummm...
-
I would gladly to this job for you for 3000 USD with shipping myself from Europe and back + parts + labor included ;D
Seriously - get the parts and do it yourself - it's a one hour job replacing all drive train with new parts. I'd get new clutch assembly as dissassembling the cluch without special tool is tricky and takes time so don't bother and buy whole clutch assembly and that will give you almost plug and play experience.
-
I would gladly to this job for you for 3000 USD with shipping myself from Europe and back + parts + labor included ;D
Seriously - get the parts and do it yourself - it's a one hour job replacing all drive train with new parts. I'd get new clutch assembly as dissassembling the cluch without special tool is tricky and takes time so don't bother and buy whole clutch assembly and that will give you almost plug and play experience.
They wanted 5 hours labour. Well...
I wanted the experience of being ripped off by a mechanic - because I have never taken a bike to a mechanic in my life. Some dream do come true :P
Parts have been ordered and will be fitted soon.
-
They wanted 5 hours labour. Well...
I wanted the experience of being ripped off by a mechanic - because I have never taken a bike to a mechanic in my life. Some dream do come true :P
Parts have been ordered and will be fitted soon.
You’ll have your reasons I’m sure, but when in a similar position 7 months ago with my 4 year-old X-Town I cut my losses and traded it in, as was, for the DTX360. Had mine just been bust CVT parts I’d have had a go at it!
-
You’ll have your reasons I’m sure, but when in a similar position 7 months ago with my 4 year-old X-Town I cut my losses and traded it in, as was, for the DTX360. Had mine just been bust CVT parts I’d have had a go at it!
I actually do remember your posts about the X-town with the transmission failure. Did you ever find out what it was - the CVT and/or the reduction gears? I think you were right in trading it in.
-
It was the Variator nut coming loose and the fan destroying the internals Mouse, crucially including stripping the splines on the drive shaft necessitating an engine split to replace it. Beyond my home mechanic skills.
I have to say, much as I liked the X-Town, the DTX360 is proving to be a worthy replacement.
-
It was the Variator nut coming loose and the fan destroying the internals Mouse, crucially including stripping the splines on the drive shaft necessitating an engine split to replace it. Beyond my home mechanic skills.
I have to say, much as I liked the X-Town, the DTX360 is proving to be a worthy replacement.
WoooWee!
If that ain't a warning to properly torque those 2 CVT nuts!!
CVT parts are one price...but, destroying the splines is a horror phone call from the mechanic!
Yeah, "sorta tight" is not good enough!...
Good reminder.
Stig
-
Update:
Mechanic wants $3000 just for the 2x front pulleys, ramp plate 2x rear pulleys, sliders, rollers and belt plus 5 hours total for labor. Not including the clutch shoes or springs which is surprisingly undamaged.
Ummm...
I think he is Politely telling you to Go away.
Do they have any good used parts on eBay where you live? Taken from a crashed scooter.
Do buy a new belt though.
Stig
-
It was the Variator nut coming loose and the fan destroying the internals Mouse, crucially including stripping the splines on the drive shaft necessitating an engine split to replace it. Beyond my home mechanic skills.
I have to say, much as I liked the X-Town, the DTX360 is proving to be a worthy replacement.
This actually happened to me in my previous bike, the DT300i. But it was eventually nearing 80,000km so I decided that was the end.
-
I think he is Politely telling you to Go away.
Do they have any good used parts on eBay where you live? Taken from a crashed scooter.
Do buy a new belt though.
Stig
Parts are already ordered for DIY.
It was the Variator nut coming loose and the fan destroying the internals Mouse, crucially including stripping the splines on the drive shaft necessitating an engine split to replace it. Beyond my home mechanic skills.
I have to say, much as I liked the X-Town, the DTX360 is proving to be a worthy replacement.
I think the DTX360 is a cool bike, a decent evolution of the DT350.
-
WoooWee!
If that ain't a warning to properly torque those 2 CVT nuts!!
CVT parts are one price...but, destroying the splines is a horror phone call from the mechanic!
Yeah, "sorta tight" is not good enough!...
Good reminder.
Stig
Too true Stig. Some of the guys on here thought I might clean the splines up sufficiently (by picking out the molten aluminium*), but I wasn't brave enough...
* Yes, that IS spelt correctly ;)
-
Woooouw, you guys over there must be rich😉.
I get in line too, to come to fix it together with Ericson, would bring tools.
Yes, like written, splines properly cleaned, new CVT plus nuts, belt and clutch and deal done.
-
WoooWee!
If that ain't a warning to properly torque those 2 CVT nuts!!
CVT parts are one price...but, destroying the splines is a horror phone call from the mechanic!
Yeah, "sorta tight" is not good enough!...
Good reminder.
Stig
@Stig, this outer front pulley/ pulleys being made from relative soft aluminium/dural, I learned lately at a discussion with an middleaged scooter dealer/ mechanic, is actually a safety feature.
To safe your crankshaft/motor/rear gear from destructive force by a blocked CVT (which as a possibility is taken into consideration by KYMCO engineers) you have a pretty inexpensive (compared to a whole motor) piece, which gives in, in case, and is easy to replace.
-
Here are aftermath photos. 1 broken roller with a flat spot and also a flat spot on the ramp plate. Pulley wear surfaces seem fine with slight grooves, clutch has a bit of glazing and bell has a bit of discolouring from overheating. Belt is good but will be replaced. Otherwise a bit of a clean/sand and it can be put back.
-
Photo 2 of the roller
-
can someone walk me through the process of how a broken roller would cause the clutch to be always engaged? Clutch engagement is RPM dependent...I can see how a broken roller may help open up the front pulley..maybe change the belt position a bit..but why would this engage the clutch? (still on 1st cup of coffee this morning..)
-
Mouse, yes, roller got stuck, chafed off its coat, disintegrated, jumped out, blocked the transmission, rest we know.
Check carefully before asambling, splines, treads (with new nuts).
If the rear pulley and clutch is visually good and not demaged, take it again. Slight grooves (under 0.5mm) don't matter.
Clutch bell: measure carefully its "roundness" with a caliper. Preferable a digital. Inner diameter is 160mm (tolerance 0.3mm)
Torque front pulley nut 135nm
Torque rear pulley (clutch) 80nm
If you have clutch and rear pulley out,mount the belt already out on you bench between pulleys (as deep as possible), makes it easier to mount front pulley assy correctely.
When you mount all this, before you put the belt on its front pulley, let the motor run and watch the crankshaft whether its running without tumbling.
And this all for a little bit under €3.000,-😊
-
can someone walk me through the process of how a broken roller would cause the clutch to be always engaged? Clutch engagement is RPM dependent...I can see how a broken roller may help open up the front pulley..maybe change the belt position a bit..but why would this engage the clutch? (still on 1st cup of coffee this morning..)
My theory:
Like written above, broken pieces were between belt and front pulley, tensioned belt, clutch engaged.
Maybe also a little bit too small (diameter) rollers.
1/2 mm would make a difference after some yrs.
-
can someone walk me through the process of how a broken roller would cause the clutch to be always engaged? Clutch engagement is RPM dependent...I can see how a broken roller may help open up the front pulley..maybe change the belt position a bit..but why would this engage the clutch? (still on 1st cup of coffee this morning..)
I'm thinking the roller with the flat spot jammed the variator and wouldn't roll back, so the belt was stuck riding in the highest position. This would cause a high ratio and the rear pulley to spin faster, fast enough to engage the clutch and cause the rear wheel to spin at idle.
Photo 3 below of the pulleys and clutch assembly.
-
Photo 4: the splines on the front shaft. They look intact. Same condition as the rear.
-
Photo 5: close-up of the clutch shoes on the clutch assembly. A bit of glazing.
-
Photo 6: close up of the flat spot on the ramp plate.
-
Does not look that bad! New rollers or gliders, sliders too, a rampplate, belt, new nuts and off you go.
If this ramp plate is still straight, I would polish it, brake and smooth the edges and let it be.
Watch for deadplay front pulley/splines.
-
Does not look that bad! New rollers or gliders, sliders too, a rampplate, belt, new nuts and off you go.
If this ramp plate is still straight, I would polish it, brake and smooth the edges and let it be.
Watch for deadplay front pulley/splines.
It's good news for me - the parts to be replaced are relatively inexpensive and the repair job is pretty straightforward. I will complete it when all the parts arrive.
-
Mouse, this ramp plate looks at 2nd view overall a little bit rough to me, IF you get a new one, compare, IF NOT, do a thorough smoothing and polishing on that. Though the inner ingranation looks too rounded to me.
Breaking edges too.
Dr. P or TechPülley gliders/squares in right dimension might be an idea too, to avoid such an event.
-
Mouse, this ramp plate looks at 2nd view overall a little bit rough to me, IF you get a new one, compare, IF NOT, do a thorough smoothing and polishing on that. Though the inner ingranation looks too rounded to me.
Breaking edges too.
Dr. P or TechPülley gliders/squares in right dimension might be an idea too, to avoid such an event.
Already ordered a new ramp plate. That flat spot from the roller in the pic isn't going to buff out.
-
So from the repair/service manual, the causes of rear wheel spin on idle or loss of power (from the CVT/transmisiion) are:
Engine starts but motorcycle won't move
• Worn drive belt
• Broken ramp plate
• Worn or damaged clutch lining
• Broken driven face spring
Engine stalls or motorcycle creeps
• Broken clutch weight spring
Lack of power
• Worn drive belt
• Weak driven face spring
• Worn weight roller
• Faulty driven face
For me, a worn weight roller was correct!
-
Mousejunks, sorry this happened to you but thank you for walking the rest of us through your discovery process. It's very interesting and satisfying to follow these issues through to conclusion. Hope you're back riding, soon!
-
I wonder what brand of rollers your shop installed which grenaded after 10,000km?
This is a first for me - a roller failure!
Stig
-
I wonder what brand of rollers your shop installed which grenaded after 10,000km?
This is a first for me - a roller failure!
Stig
Rollers were genuine Kymco from Taiwan.
On closer inspection, grime build-up in the roller grooves of the variator might have caused the rollers to become stuck. The flat spot developed on the plastic shell first and then eroded through to the metal.
Unknown why the grime was so oily, there were no leaks in the CVT seals. Possibly 3 years of wet weather and road grime.
-
All CVT parts finally arrived installed. Works perfectly and no more transmission issues. Nuts torqued to 100Nm and 60Nm as per the service manual.
-
Congrats👍
....🥂
-
Hey Mouse,
Glad to see you're up and running again. I am curious as to whether or not you ascertained the need for all new parts from your "mechanic" or upon your final inspection persuade you? I can't imagine such a new bike as yours needing a new face plate unless it really got damaged or gouged badly. All I did with mine was to clean it out good with solvent and buff the roller valleys and it was good as new.
The reason I inquire is that I had 2 rollers go to Crap City on me once and all I did was replace all the rollers, and being that they had over 50000 miles on them I should have done that replacement miles earlier but failed to use proper judgement. Not ever having owned or had problems with rollers it was a learning experience.
Just out of curiosity how were able to squeeze the belt back onto the clutch assy before looping over variator plate? I usually have to beat it into the clutch plates using deadblow and a cut down to size 2x4.
Again kudos on the finished job!
-
Hey Mouse,
Glad to see you're up and running again. I am curious as to whether or not you ascertained the need for all new parts from your "mechanic" or upon your final inspection persuade you? I can't imagine such a new bike as yours needing a new face plate unless it really got damaged or gouged badly. All I did with mine was to clean it out good with solvent and buff the roller valleys and it was good as new.
The reason I inquire is that I had 2 rollers go to Crap City on me once and all I did was replace all the rollers, and being that they had over 50000 miles on them I should have done that replacement miles earlier but failed to use proper judgement. Not ever having owned or had problems with rollers it was a learning experience.
Just out of curiosity how were able to squeeze the belt back onto the clutch assy before looping over variator plate? I usually have to beat it into the clutch plates using deadblow and a cut down to size 2x4.
Again kudos on the finished job!
The mechanic wanted to replace nearly all the parts in the CVT - I said no and took the bike back.
The only parts that were replaced were the ramp plate, sliders and rollers. The ramp plate was gouged by the flat spot on the roller.
Funnily enough my previous Kymco had 80,000km and the pulleys, ramp plate and clutch were never replaced. They were fine.
For the clutch, you have to squeeze the pulley very hard with two hands. It can be done.
-
For the clutch, you have to squeeze the pulley very hard with two hands. It can be done.
If you can't squeeze the clutch with hands try to rotate it 45 degrees. Once I was trying to squeeze it so hard that my fingers hurt for next two days but I just could do it. Then I rotetet clutch 45 degrees and it was much easier to squeeze.