Britbike forum Forums British Motorcycle specific Brands Triumph bulletin board Primary Case removal

Trying to get the primary cover off my 1970 TR6....removed the 2 domed nuts and the 8 allen key bolts and whilst there is the smallest hint of movement it seems pretty reluctant to come off. The manual appears to show it simply comes off but is there something else I need to loosen (clutch related) that is holding it on from the inside perhaps?
Cheers, Steve

No there's nothing more, it should come right off. No dowels either, but heavy tightening of the domed nuts sometimes distort the covers badly, so the holes may grip around the studs.
Or someone may have used some tough sealer on it, working around it with a mallet should help.

I was thinking you had to slack off the chain adjuster.

No you don't, it has nothing to do with the cover at all.

Whatever you do, don't try to lever it off.
Possibly a hot air gun might help loosen any sealant

Yes, it absolutely does. The primary chain tensioner hollow nut must be backed off and separated from the tensioner before the cover will come off.

Hi Mark Z, Interesting.... What motor do you have? I find on the unit 650s I've worked on the primary adjuster is in the crank case side of primary, so the cover comes off without having to disturb the chain or adjuster in any way.

Steve, As was suggested sounds like your gasket is holding tight, as well as possibly the stud holes. Heating with heat gun or hair dryer is a good idea. You might remove the clutch adjuster plug & put a hook in the hole & pull on the cover while tapping with plastic or rubber hammer. Don't bend the cover or break it. Also you might try very gently prying between rear motor mount side plate & cover while pulling with hook. Also you could remove the timing inspection cover & pull there with hook. The front end might not be stuck so tight.

Problem is the cover is thin & weak with no good way to hit or pry on it. So go easy & take your time. Covers are not cheap. I'll often grease the gasket on motor side to keep it from sticking so bad.

Going back on I got a bunch of bolts & cut the heads & put a screw driver slot in them. I screw them in leaving about 3/16" of shaft exposed. Then grease inside ( or both sides if you prefer) of gasket. Hang gasket on the screw stubs. The offer up cover. Remove stubs one at a time & install real screw, but not quite tight . After all real screws are in final tighten the screws & nuts. Fast & easy guarantees gasket stays properly positioned.
Don

"The hollow nut" would be the tensioner nut that goes on the spoke? It sits in the case itself, not in the cover...
It will need to be backed off to remove the primary chain and sprockets, you may possibly confuse with that?
I'm removing primary covers quite often, so I'm not saying my opinion, I'm stating the facts... I'm wrong with alarming frequency, as on the Norton Forum last night, but not this time...

Interesting method, I might try it next time. Thanks for the tip Don.

Thanks Don, Mark and others - success! After a lot of gentle hammer tapping there was a tiny gap and I could get a razor blade to gently cut through the seal and it then came off easily. Strangely no gasket so presumably previously the mechanic simply used a bond of some sort which then caused the problem.

Good advice to grease motor side when it goes back on, cheers

Steve

I've only ever use a three bond type sealant on the primary, when it's time for removal i brush a little paint thinner along the join.

Rod

Thanks Rod, interesting and useful info

Steve

I guess it's academic at this point, but I stand corrected on my statements about the chain tensioner. My experience with Triumph primary covers is based on a T140 and a TR5T, so I ASSumed that all Triumph unit twins were the same.

Steve, suggest using a gasket and cementing it only to the cover. Then the cover can come off again without disturbing or damaging the gasket. As long as the mating surface of the case is in good condition (i.e., no gouges), it won't leak. (Yeh grease on the motor side.)

Not to be a pain in the butt my friend, but the T140 primary cover isn't any different in that respect, and the same goes for every C series primary I've worked on. If the TR5T is different I couldn't say, as I've never worked on one, but I really don't think so.

No problem; persistence is a virtue. The T140 is long gone, but the TR5T is still in my garage. I just went down and took a look, and the tensioner "nut" is in the cover. I just had the cover off to change the clutch trap door oil seal, and somehow I knew that that nut had to come out to get the cover off. I chalked that up to the T140, which is the only other Triumph of which I've had that cover off. It was ten years ago, but I remember puzzling over why the cover wouldn't come off until I figured out what was going on. And I remember making that "special tool" to get the nut out of the cover, which I saved, and which worked for the TR5T as well.