T20 stick feedback

[cclingma]

I just got my my old Briggs opposed twin runing and put the belt to the T20 on for a chance to turn my freshened up transmission for the first time. I just wanted to see the output sprockets turn with no chains or load on them. Question comes when I shift into forward and push both sticks forward a little to watch the T20 work. Seems I get a little thump thump vibration from the trans back into the stick that I can feel as I press forward. Should I be worried?

[jpswift1]

Something isn't right.....there shouldn't be a "thump, thump, thump" vibration felt in the sticks. Something tells me there is a piece in there that worked its way loose or out of position.

[cclingma]

I should have added that I only feel it on the drivers side stick. Sounds like I may have to open the T20 up ..... Again.

[jpswift1]

It sucks having to open it up again, but you'll probably be happy you did down the road. The pin that holds the bands in may have come loose, it could be a bearing, it could be an issue with something binding up that fell out of place. Let us know what you see, because I'm interested to know what it could be.

[cclingma]

I could use some more T20 education. It seems that the stick is really only kind of wiggling forward and back when the rpms increase. It doesn't matter whether I'm in forward, reverse, or neutral. I'm curious what all even turns in neutral. It feels like what I would expect if one of the drums was a tad out of round. Is that even something that happens? Seems those drums were nice heavy material???

[cclingma]

Sorry to keep beating this to death but thought I'd share a possibility for anyone else that may find this post while researching similar problems. I've been scouring this forum and found a post where someone else had shaky laterals and it ended up being a broken tab on one of those washers with the retaining tab. Still waiting for an opportunity to open mine up.

[cclingma]

So I opened the T20 back up and found the medium sized thrust/fiber washer damaged on the input/left side. I say medium sized because of it's diameter as it's actually thicker than any of the others I believe. I replaced it with one of the originals and put the trans back together. Spun it with a drill and all looked good. Put it back in the machine and it was silky smooth....at first. Now it's right back to shaking the driver side lateral.

I'm stuck! The damage to the washer I removed would suggest that it popped out if the recessed ring that holds it in place. Since I'm right back where I was I can only imagine that washer is eaten up again.

Any ideas would be greatly appreciated!

[Mike]

Could it be a bent shaft?

[cclingma]

You know Mike I certainly can't say I've done anything to rule out a bent shaft. I'm going to have to open it up again for sure no matter what. I did have a very good conversation with a fella from Recreatives when I called to order more thrust washers. He was concerned that something has worn allowing the medium sized thrust washer to slip out. The fact that it runs smooth for a little while makes it seem that the washer is in place to begin with and pops out after a few minutes of running. This man gave me a lot of good info. Turns out that the recessed ring cut in the drum to hold the medium sized thrust washer should be about .045". Less will allow the washer to work out. He also said to measure how much end play exist between the planitary drum and the center plate surface that the planitary drum rides against. This measurement should be in the .025" ball park. If the end play is more than .040" to .045" you have a situation that will allow that medium thrust washer to jump out and do what mine is doing. He had ideas as to what could cause this excessive end play that included worn center plate, damaged/worn recessed grove that holds the thrust washer in place, and of course missing thrust washers. He also offered a few ideas of ways to shim to correct this problem if it is in fact a wear issue.

[jpswift1]

The folks at Recreatives are VERY helpful. If it does happen to be a bent main input shaft I have an extra one for sale.

[micmac]

I had a pulse in one of my Laterals on my Max IV. I rebuilt the entire unit bearings seals etc. Thought it was the main input shaft that was bent. Instead it turned out to be the secondary clutch was wobbling slightly on the shaft. The mounting hole on the secondary was egged slightly causing the problem. Replaced the secondary and it went away. Not saying that's the problem but you might want to check it before you open up the T- 20 again.

[cclingma]

I appreciate all the ideas here guys. I'm looking for a opportunity to look this thing over again.

JPswift-I'll keep you in mind on the shaft.

Micmac-Was your secondary loose enough on the shaft that you could feel play by just trying to rock the clutch side to side?

Thanks

[micmac]

No that is just normal on some T-20s I have two one has the play you describe the other doesn't. I spoke to Don about this and as long as it's not excessive its ok.