Triumphrat

Ratbike · 12-25-2007

(Sorry, I also posted this in another forum)

Hi all! I'm restoring a '69 TR6 bobber, and I've got a problem that's got me stumped. I've rebuilt the entire clutch, pushrod, plates and all. I can have the bike on the jack, and put it into and out of gear static all day. When I crank the engine and I put it into gear (with a tiny bit of grinding, nothing like what it was before I tore down the clutch) it's in gear, and bogs down the engine of course. After it's bogged down I can then take it out of gear no prob. This happens everytime I try to actually get her moving under her own power. I've tinkered with the clutch cable tension till I'm blue in the face. Is there anything I might be missing that I should look at? There's no one in my area to ask, so I'm learning as I go here. Any suggestions you might have, I'd appreciate it. Thanks!

6t · 12-25-2007

I think that sticking clutch plates may be your problem, new plates or not.
The last Meriden Bonneville I had was a 750 5 speed OIF. The clutch plates were always sticking. I had to rock it back and forth in gear before staring in order to free up the clutch plates. I replaced the plates with a new Barnett clutch assy, still had to rock it to free them up. Occaisionaly I would get pissed off, start the bike and jam it into gear. It felt good at the time but doing that may break off a tooth on the 1st gear. The 1st and 2nd gear are on the same cluster. I know that as I replaced two of them!
Good luck.

RonD · 12-26-2007

1- make shure youre clutch basket is not grooved.
2-the tangs in your plates are a nice sliding fit
3-make shure your plates are dead flat and clean
4-adjust your clutch pressure plate to lift dead sqare
5-most important make shure you have the thing adjusted so that there is plenty of lift when you pull your cluch in, it might be just free going through the gears stationary, but it should free up fairley early in the clutch lever travel ,and go realy loose when the clutch lever is fully engaged, and i suspect this is your problem your not opening the clearance up far enough with your pushrod lever adjustment..

Mecchanica · 12-26-2007

First, was this behavior present BEFORE you rebuilt the clutch? If so, has it improved or gotten worse?
Second, what happens if you try to ride it, that is accelerate with the bike off the jack?

Ratbike · 12-26-2007

Wow. What a response! Thanks to all for your help. I'm pretty new at this, so bear with me, and I'll try to answer all questions in this post. I bought this bike off an old gent who was no longer able to ride. When I got to his place, we fired it up, and he wanted to take it around his yard one final time. He struggled to get it into gear, which sounded like an out of control coffee grinder, and it would never move more than a few yards before she gave up the ghost and died. It also was burning oil like mad, and the brakes were shot. I knew it would be a full on restoration project. (My first attempt at one) I tore down the engine with the help of my trusty Haynes manual, and replaced the rings, various gaskets, adjusted the valves, rebuilt the brakes, did some wiring, had the right head welded as there was a crack at the exhaust attach point, new pipes, etc.

Once I did all that, I took apart the clutch. The clutch drum had obvious wear from the plates contacting it. From the looks of it, I don't think the clutch had seen the light of day since the factory. I filed down the wear in the clutch drum evenly, and made sure it was still in tolerances, per the manual. I ordered new plates, and a new pushrod. I checked the plates on a glass pane to make sure they were true, and went through several push rods before I got one that was the correct length. All the bearings were ok, so I then reassembled the whole shebang. The plates fit the clutch drum fine. I adjusted the clutch plate as best I could. I don't have a lot of custom tools, so if you have a trick to make sure it's completely level and true other than the Mark 1, Mod 0 Eyeball, I'd love to hear it. I'm on a somewhat limited budget here. LOL Like I said, I'm just starting in all of this. It's been a lot of fun till now. Now I'm just stumped.

So, after reassembly, the clutch moves through all the gears static just fine, which it would not do prior to me tearing the clutch down. It will go into gear with a very slight grinding of the gears, (and I do mean very slight) after I start her (third kick every time, yeah, I'm proud!) but with the clutch lever fully depressed, it [u]is in gear[u] and thus bogs the engine down. Once she's shut down, she is in 1st gear till I put it back into neutral. I suppose it is possible that the plates are just sticking, but wouldn't you think they would break loose after 2 or 3 attempts to engage the gears? I don't know. Mecchanica, I haven't actually tried to ride her yet. I may attempt that this Friday, if the weather holds out here. If there is any other info that I can give to you gents to help figure out this mystery, I'll be happy to provide it! Again, thanks for all the input so far. I'm really impressed with this site. (And whoever moved my thread, thanks for putting it in the right place.)

Mecchanica · 12-26-2007

As the engine bogs, does it try to push the bike forward, as it would do with the plates partially engaging? If so, then the problem is either a clutch adjustment problem or a problem with the gearbox, perhaps some seized bearings or bushings.
If it bogs and doesn't try to push the bike, then it could be the engine binding up....but that would happen regardless of the clutch or gearbox. So, with a fan on the fins, run the engine as you did in the first test, but don't engage the gears. If it can run for four or five minutes without bogging, then the problem isn't the engine.
Potential sources of binding are the rod bearings....but if they bind even once, they don't usually loosen....or the pistons sticking in the bores. These will often loosen when they cool, especially if the seizure was less than total.

Ratbike · 12-26-2007

It does try to move the bike forward when I put it in gear. Also, the engine idles/revs just fine. I've got short shots on it. It's obnoxious loud. Perhaps it is just a clutch plate adjustment. There wasn't any suggestion on how far out the clutch plate should move after installing it in my manual. It moves a little less than 3/8" I'm guessing. I've got the cover back on it now. Also, my attempt at making sure the clutch plate was level was to count the exposed threads on the mounting bolts, and look at it as I actuated the clutch. I'm sure there's a better way to do it, I just don't know what it is.

Mecchanica · 12-26-2007

First, pull the primary cover.
To get the plate to lift evenly, adjust the rod first....slack the cable all the way, loosen the locknut and with a socket, hold the nut to keep it from turning while you use a screwdriver THROUGH the square hole in the socket to turn in the screw until it bottoms on the rod and just lifts the plate. Back off and then LIGHTLY bottom the screw. Back the screw out 3/4 of a revolution if you have the stock steel pressure plate, half a revolution if you have one of the MAP alloy plates with the coarse thread adjuster. Tighten the lock nut while holding the screw with a screwdriver.
Adjust the cable to have a little slack, so that the lever can "bounce" just a little.
Now straddle the bike, pull the clutch lever, and slowly kick it over. Watch the plate. If it wobbles, then screw down on the nut closest to the high point, a little at a time. If you have to, then loosen the nuts opposite the high spot by a little.
Might as well adjust the primary chain as long are you are in that far.
Have someone sit on the bike to load the rear chain. Check the rear chain tension. Should have about 5/8" total up and down movement with ten pounds of force. When that is done, with the assistant sill sitting on the bike, adjust the primary chain to get 3/8" total up and down with ten pounds of force.
Button it up and add a third of a quart of whatever oil you are using in the engine to the primary case.
I suggest 10-30 Synthetic motor oil, "non-energy conserving". The energy conserving types have phosphates and sulfides which are not good for the clutch when they become imbedded in the surfaces, and you don't need any more problems with that.
Most people overlook the surface finish of the plain plates. I strongly suggest that you sandblast them with medium coarse garnet. They should be rough enough to catch your thumbnail. If your clutch both drags with the lever in, and slips even with fairly strong spring pressure, then almost certainly you have too-smooth plain plates.

#####...WUPS, Yours is a 69 so it doesn't share the engine oil. For the earlier bikes, the best oil for the primary is the synthetic ATF....atf is designed for lubing gears and chains, is non-foaming, thermally stable, and to operate hydraulic systems and wet clutches. #####

Ratbike · 12-26-2007

Thanks M! I'll get on that this weekend. I'll let you know how it goes.

OzBloke · 12-26-2007

Ratbike,

To check for clutch pressure plate running true during disengagement, the simplest/cheapest method is what you've been doing. With primary cover off, gearbox in neutral, clutch lever half-actuated and just starting to move the pressure plate, use the kickstart level to rotate clutch, and look for wobble as the outer (domed) plate rotates. If you see a "hump" screw the closet spring/nut in a bit. Keep doing this till the plate rotate without perceiveable "wobble" with your calibrated eyeball. Better yet, get a mate to do the looking while you do the clutch lever and kick starter thing.

Hope this helps.