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2 stroke wet clutch sticks every day - plates look ok?

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Hi folks, this is my first post here. I have a 2006 Gilera SMT (like a Derbi Senda) which is a little 50cc, 2 stroke, 6 speed Spanish/Italian bike.

I got it used a year ago, so I don't know the first 10 years of its history. I can't remember for sure if this problem was already present sporadically when I bought the bike, or if it started after the bike sat several months - but I know for sure that after it sat several months, it has been an issue ever since.

The bike has a wet clutch, and the clutch sticks. A lot. It used to be that it'd stick first thing in the morning if I hadn't ridden it in a few days. Now, every morning it's stuck. Through trial and error I figured out that by putting it into first and rolling the bike forward and backward eventually I can get it to let go. Once it does, it shifts and runs just fine for the session. Then sometimes on my return from work it's a tiny bit sticky, and sometimes not. The way it's stuck in the morning, I can't even start it without unsticking it first, the bike just lurches forward when I kick it over.

I first read and did some checking on the clutch cable, tried adjusting it a little bit, but it seemed to be where it should be, and tightening it up a bit didn't help.

I changed the oil to make sure that it was the correct kind. The manual asked for 80w90 GL4 gear oil, which is what I used. (It's conventional oil which is all I have available here in West Africa.) The oil change didn't help anything.

So, I moved on to assuming the clutch plates might be original (16,000 miles) and need to be changed. That didn't totally make sense, since they never slip (and how good do they need to be to contain 50cc's worth of power, lol), but I figured it might have been stored for a long time improperly or something.

I opened it up today, and although this is my first experience with a bike clutch, it all looks pretty good to me.

What do you guys think? Where else should I be looking?

Image920668906260722041.jpg

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That's not uncommon. My trials bike does it if it sits for a few days. Oil does make a big difference, and regular gear oil like you're using is usually the worst. I found Maxima MTL Light is good in my bike, but probably not available there. Can you get regular ATF transmission fluid? That usually works well and most of the time makes the sticking stop. Otherwise, just do what you are doing, just rock it some before you start the engine. A higher gear is usually better but might not matter on a 50.

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Normal for a clutch to stick when cold, especially with the heavy gear oil recommended for that engine. As long as doesn't drag or slip once warmed up then all is good. Are you starting the engine in gear? Try starting it in neutral. 

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Also, look at your clutch basket and inner hub for notching. The tabs of the plates moving when you operate the clutch lever tends to wear little notches in the basket and hub.  While the engine is running, notching will hold the plates together even when you pull the clutch lever.

Is it still shifting smoothly while you ride?  Notching will also make shifting more rough.

 

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Your clutch looks OK but it's hard to tell from a photo. I have noticed sticking clutches on several of my vehicles. I'm talking about cars, trucks, tractors, motorcycles and 4 wheelers. If these sit for a month or more I will disengage the clutch with duct tape, rope, blocks, etc so that the plates are not under the constant compressive force of the clutch springs. This has never failed me. Once I forgot and it took a tow from my tractor to get my truck's clutch to break loose. Of course, inspect your clutch for defects or warpage in the clutch basket and plates.

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I have found from decades of owning 2 strokes that ATF Type F works great, is cheap, available almost everywhere, and changes clutches from sticking to not, plus shifts better, and less grabby. Just change the ATF more often than gear oil.  Might want to soak the fiber plates in the fluid for a day or two prior to install if their already out of the bike.

Edited by mrdsee

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Steel clutch disks are stamped out on a press so that one side is sharp and the other is dull, rounded. The sharp ends all go in the disengagement direction where you are doing the work with your hand. The clutch springs are not as strong as your hand. It makes for smoother engagement.

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Thanks for the input, all. I got it put back together, everything's still working the same, but now that I know to unstick it in 2nd instead of 1st (waaay easier and less reefing on the sprockets/chain) and that it's not a sign of something else breaking, I'm fine going forward.

Thanks a lot!

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:ride:Use a ziptie or piece of wire to hold lever pulled in when starting first thing so it warms up the oil and lubes up the clutch, hope that helps ya,...been doing that on every bike I ever had and never had a sticking problem, just my 2cts,:cheers:

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