Clutch Question. Why does this keep happening?

[Falcone]

I'm just wondering why this keeps happening. Using a hillard extreme duty on my slightly modded gx160. 26lb springs,billet stuff, gx390 carb.About 6k is all I take it to (bike is in my sig). The clutch is rated to 5k. Is it as simple as this. I know the hillards are pos's, but its strange. What they turn into after a short period of time

The clutch in the picture had maybe eight hours on it. Seven of them were on a tec H50 with the gouvernor (but the teeth were worn, but not horribly. Within an hour on the gx, this was the result. It happened on a high speed run too, that was fun. The engine is completly straight.

Clutch 2. No pic, took it back. About three hours. On a long ride with a buddy, my chain started slipping alot. Looked at the teeth, and they were like shark teeth, super jagged. Nursed it back home at low speeds and took the clutch back for a new one.

Now the new one is doing it. I'll try a new clutch out next, but has anyone else ever had this happen? This has only cost me one clutch, its not like I keep buying them. They are going to return my money next time, as my application is inproper for the clutch.

What should I try? I do alot of riding on crazy terrain with mud and rocks, lots of hills and I hit a few trees. Also do a little on roads at top speed because its fun racing cars. Any help would be appreciated. Cheers

 

[Harleys Papa]

How tight is your chain? What does your rear sprocket look like?

 

[buckeye]

I guess I am learning. My though was chaim too tight or wrong chain.

 

[Falcone]

Chain moves a little more than a half inch. Rear sproket looks the way it did when I bought it stock (used).

 

[ogygopsis]

Chain has to have too much play in it and is riding over the teeth on the clutch. The rash on the clutch housing also points to that conclusion. Been around clutches for more than sixty years and have never seen anything like this. Ogy

 

[Neck]

How old is you chain? Is it stretched to the point where the roller is catching the point of the tooth rather than settling down into the valley of the clutch sprocket?

 

[Falcone]

Chain has to have too much play in it and is riding over the teeth on the clutch. The rash on the clutch housing also points to that conclusion. Been around clutches for more than sixty years and have never seen anything like this. Ogy

That damage was from when it was mounted on the tec h50. The chain snapped (origional chain the db came with) and it wrapped around the sproket and jammed between the side cover and the clutch housing. It dead stopped the engine. From about 4k to a dead stop in under a second from the ccchhhiiinnngggg and sparks. I had to take the clutch off to get the chain off. It was something else, and the tec survived with only scuffing like the housing.

I watch the chain as I ride and it doesn't move side to side or up and down. The tensioner wheel is mounted an a door hinge that pivots where the DB one used to be. Its got a spring pulling back keeping nice tension on the chain. I can see the tensioner moving up and down with engine speed.

Nobody I have showed it too have seen this before either. I'm wondering what i'm doing wrong hahaha

How old is you chain? Is it stretched to the point where the roller is catching the point of the tooth rather than settling down into the valley of the clutch sprocket?

The chain on the clutch in the pic was an hour old. When the chain snapped on the H50 from being old and crappy, I swapped the gx160 and new chain on the DB. Put a new one on, then it just exploded into a couple pieces yesterday. Its from princess auto (HF equivelint for canuks) so its crap. Could the chain quality be causing this?

 

[george3]

engine shaft is bent or the rear sprocket is out of round goes up and down. that will do it. or your chain is a pos. three choises. pick one. lol, buy american

 

[graygoose420]

What chain do u have .is the clutch 40/41 chain or 35? Look like u used 35 chain on a 40/41 clutch . That's why the teeth on the clutch got Sharp.:shrug:

 

[george3]

Looks like it was a 12 tooth 35 clutch. hillard extreme duty? I wonder how their standard duty is?

 

[Oldsalt]

I'm with ogygopsis on this. Been to two County Fairs and three Mexican goat roapings and thought I'd seen it all, but couldn't believe my eyes when looking at the photos. However, you last post enlightened me as to what is happening.

It is not really possible to use a spring loaded tensioner on a chain drive that has reversing forces. If the spring loaded tensioner is on the bottom strand of chain all is well until you back off the throttle. In that condition the rear wheel is driving the engine, rather than vice versa, and the tight run of chain is not the top one. The tight run is on the bottom and simply overcomes the spring on the tensioner. When you back off the throttle there is no way that the chain will stay deeply in the teeth of the clutch sprocket.

So one option is to use a spring with a really high rate. I would not try that because you will be ruining more clutches until you find a spring strong enough and you will have added a lot of unnecessary strain on the drive system due to the gargantuan spring. IMHO you should make the 'roller' fixed and not spring loaded.

 

[george3]

I'm with ogygopsis on this. Been to two County Fairs and three Mexican goat roapings and thought I'd seen it all, but couldn't believe my eyes when looking at the photos. However, you last post enlightened me as to what is happening.

It is not really possible to use a spring loaded tensioner on a chain drive that has reversing forces. If the spring loaded tensioner is on the bottom strand of chain all is well until you back off the throttle. In that condition the rear wheel is driving the engine, rather than vice versa, and the tight run of chain is not the top one. The tight run is on the bottom and simply overcomes the spring on the tensioner. When you back off the throttle there is no way that the chain will stay deeply in the teeth of the clutch sprocket.

So one option is to use a spring with a really high rate. I would not try that because you will be ruining more clutches until you find a spring strong enough and you will have added a lot of unnecessary strain on the drive system due to the gargantuan spring. IMHO you should make the 'roller' fixed and not spring loaded.

well I guess we will ad 1 more option. to low of spring tension. Making the chain jump on the drive could be it. If the tensioner is on the bottom spring loaded toward the rear sprocket Like a motor cycle not reversed, and the angle parallel with the chain or close with decent tension not 300 lbs. but decent and the rear sprocket does not go up and down 1/4 out of round it should work great I have done this before and it works great. but he has something wrong or mickey moused. the chain is jumping the driver. or loose and tight or who knows the bike isn't here to see the truth, lol

 

[mmisterbungl]

You must be hearing an awful noise when riding if this is happening, shouldn't you? :shrug: Do you hear grinding, clinging, etc?

 

[Falcone]

engine shaft is bent or the rear sprocket is out of round goes up and down. that will do it. or your chain is a pos. three choises. pick one. lol, buy american

Engine shaft is straight. Its been torn down and inspected. Chain is a pos, its the 10ft china bulk crap. But would it have THIS much effect on the clutch sproket? And I will check the wheel sproket today. It is very possible i've bent it, I hit alot of stuff on trails. Thanks for the tip

What chain do u have .is the clutch 40/41 chain or 35? Look like u used 35 chain on a 40/41 clutch . That's why the teeth on the clutch got Sharp.:shrug:

Man, just because I modify Volvo's and race them, does not mean i'm that retarded:laugh: If this was the case though, it would totally explain it.

Looks like it was a 12 tooth 35 clutch. hillard extreme duty? I wonder how their standard duty is?

Bingo. I wouldn't touch a standard quality one now hahaha

I'm with ogygopsis on this. Been to two County Fairs and three Mexican goat roapings and thought I'd seen it all, but couldn't believe my eyes when looking at the photos. However, you last post enlightened me as to what is happening.

It is not really possible to use a spring loaded tensioner on a chain drive that has reversing forces. If the spring loaded tensioner is on the bottom strand of chain all is well until you back off the throttle. In that condition the rear wheel is driving the engine, rather than vice versa, and the tight run of chain is not the top one. The tight run is on the bottom and simply overcomes the spring on the tensioner. When you back off the throttle there is no way that the chain will stay deeply in the teeth of the clutch sprocket.

So one option is to use a spring with a really high rate. I would not try that because you will be ruining more clutches until you find a spring strong enough and you will have added a lot of unnecessary strain on the drive system due to the gargantuan spring. IMHO you should make the 'roller' fixed and not spring loaded.

Well sh!t. Thank you very much. I am using a door spring, the kind from the glassdoors with the hydraulic piston. It keeps it tight, but your right, when the throttle rapidly shuts after wot, the tensioner does move quite a bit, but the chain never "looks" loose. I'll cut up some flat stock and make a stationary tensioner/roller today.

I'll report back, but I thought this would work out great, its kind of like a motor cycle tensioner, and I use the same kind of thing on one of my volvo's for years to keep the serpentine belt on the crank and alternator since I took out power steering and a/c and use a short belt. I can't move my engine (well I could, but i'd need to lengthen the holes), so I wanted an automatic tensioner for when the crappy chain stretches. But i'll try a stationary one out, and maybe modify my holes

You must be hearing an awful noise when riding if this is happening, shouldn't you? :shrug: Do you hear grinding, clinging, etc?

Believe it or not, no. That is until the one in the pic rounded at fullspeed,it sounded like I dropped a few rods in a car.


I'll take a picture of the tensioner set-up, and the sprokets and chain alignment and post it up. Then i'll take it apart. Thanks again everyone for the help/tips. This is weird

 

[Oldsalt]

Look at the pic of the worn sprocket teeth. You'll note that the wear pattern is indicative of a chain going faster than the sprocket. The tallest 'peaks' on the worn-out sprocket would point the other way if the sprocket was going faster than the chain.

The belt tensioner [spring loaded] on your Volvo's serpentine belt should and does work because, as I mentioned earlier, there are no 'reversing forces'. Unless one wishes to believe the air conditioner and alternator are trying to drive the Volvo engine in the same manner that the rear wheel drives your minibike engine when you back off the throttle.

If a chain drive, with reversing forces, had low enough torque on the shafts a spring loaded tensioner would work, to keep the sprocket teeth engaged, as not much would be demanded of it. But it is in the same class of logic as powering a wrist watch with a diesel engine. Can be done, but it does not make any sense.

 

[george3]

Mx bikes use this method all the time. spring loded tentioner, with no problems but Like I said it has to be mounted correctly with decent tention, not on backwards or other problems with the drive system.