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View Full Version : Here's a video explaining why the Transmission "CLUNK" occurs!



DrDavo
06-12-2019, 09:31 AM
While visiting my Can Am Dealer parts counter I was told that the #1 question ask of the mechanics is "Why does my Spyder go CLUNK when I put it in gear?"

Anyone who owns a Spyder may be asking themselves the same question:

I was going to do a video with a part from a Spyder Tranny but the deal says they can't find the part I was going to use for the video so here is the next best option. If you did not know this, the Spyder transmission is a sequential shift type transmission much like a F1 formula racing car, in fact they look very similar inside.

There is a video out there from Driver61, who is a formula race driver, and he does a great job with the insides of the gearbox.

Once you look at this video you'll have a better idea of how your Spyder transmission is built and I'll explain why it goes CLUNK when you go from neutral to reverse or neutral to 1st gear!

https://youtu.be/XQOhuN-HHfY

So here is why it goes CLUNK!

Anytime the motor is running, with the transmission in neutral, and the clutch is disengaged such as it is anytime you are starting out first thing each trip, here is what is going on.

Even though the clutch is "open" meaning the friction plates and the clutch disc are not held tight together, the oil in the wet clutch system still allows some friction between the two clutch members and so with the tranny in neutral the "Lay shaft" will rotate! The "Lay shaft" is the engine input shaft and the output shaft is the one with the belt drive gear on it. So basically the input shaft can freewheel!

So when you put it in 1st or reverse, this input shaft, the "lay shaft" has to come to a quick stop because the engagement dogs on the gear you just engaged has now "grabbed" ahold of the required gear and so the spinning input shaft and the associated clutch disk now come to an abrupt stop and so you get this very solid "CLUNK" and all of that is NORMAL.

The same thing happens if you go from neutral to reverse but if you have noticed, it does not happen when you come out of reverse to 1st if you don't pause in neutral. That is because you have the input shaft stopped and therefore no need to "arrest" its free spinning movement again.

This shift clunk is normal for this type of tranny design and also the reason for the rear sprocket (Pulley) to be mounted in rubber shock mounts. It helps cushion the sock of bringing the input shaft to an abrupt halt!

I think if you'll take the time to watch the F1 transmission video you'll have a whole new appreciation for the Spyder transmission design.

Granted the shift dogs in the Spyder tranny are a different design from that of the F1 tranny but both will handle the input power they need to handle and give years of service.

So stop worrying over the "CLUNK", it is just part of how this design works!

I hope this helps,

Dave C.

Bob Denman
06-12-2019, 09:58 AM
Just tell folks that "Clunk happens", and they can't to a thing to change it... :opps:

Chupaca
06-12-2019, 10:04 AM
Like motorcycles (other brands) don't do it....:roflblack: We all tell them it is normal unless you can drop the RPM's it is gonna do it to various degrees....:thumbup:

stebrock
06-12-2019, 12:40 PM
Dave C.
Thanks for the info. Good post!
Rick

Spyder Insyder
06-12-2019, 12:52 PM
Like motorcycles (other brands) don't do it....:roflblack: We all tell them it is normal unless you can drop the RPM's it is gonna do it to various degrees....:thumbup:

My H-D Road King....... now that's a clunk!

Gwolf
06-12-2019, 01:12 PM
Every motorcycle I ever owned clunked when they were dropped in gear from Neutral. That is starting from a 1962 Honda Super 90 all the way to the Spyder I have now. My old Sportster with the Barnett Scorpion Clutch would almost jump the front tire off the ground when it was dropped in first. Worse when they are cold, but still a nice solid clunk even after they are warmed up. Seems perfectly normal to me. It has always been that way.

Lew L
06-12-2019, 02:01 PM
My :spyder2: " clunks" but not too bad.

The poor old, slow V-Max used to clunk but I found the secret----------- Work the clutch lever 8 or 10 times before putting the old thing in gear----- NO clunk.

Lew L

DrDavo
06-12-2019, 02:17 PM
My H-D Road King....... now that's a clunk!

The larger the diameter of the wet clutch pack the heavier the "clunk" may be when you shift into gear! It just means there is more mass rotating that has to be stopped. My old Honda Goldwing "clunked" as well.

I made the post so Spyder owners who want to be at ease could see how a sequential shift transmission is actually made. If it works for F1 race cars then it should work, and does, for our Spyders.

I should note that the engagement dogs of the Spyder gear sets are quite large and you are not going to break one just by shifting into gear.

Ride on,

Dave C.