Britbike forum
Posted By: JoejBSA TR7 leak - 03/23/21 1:45 am
Hello , purchased 1976 tiger this fall that seems to have been sitting for a while , currently have running and riding well BUT in is maiden spring voyage it seems to leak a constant amount of oil from what looks like right behind the drive sprocket. Otherwise bike is tight , could this be a wet sump issue? Or has anyone else experienced something similar?

Thanks for any and all help
Joseph
Posted By: desco Re: TR7 leak - 03/23/21 1:58 am
Triumph's rarely, if ever, have a wet sump problem. Sounds more like a gearbox seal or a seal behind the clutch. What's it smell like? Gearbox oil and engine oil don't smell the same.
Posted By: DMadigan Re: TR7 leak - 03/23/21 2:26 am
The primary chain adjuster plug is at the bottom rear of the primary case.
The breather is the right angle tube on the right side of the primary, over the gearbox.
Posted By: mondtster Re: TR7 leak - 03/23/21 5:22 am
There is both engine oil and gear oil in the area you’re describing the leak as coming from. First thing I’d do is figure out which fluid is leaking. Either probably requires a similar amount of work to cure.
Posted By: TR7RVMan Re: TR7 leak - 03/23/21 6:40 am
Hi joejBSA, Can you tell what kind of oil? Smell like gear box or motor oil?

Should you choose to diagnose, spray into front sprocket area with garden hose, spray nozzle attached. Let dry a day or two. If possible use a spare chain as this tends to rust chain. Look into area from below & from rear sprocket area looking forwards. Mirrors can be helpful. Make sure it's dry. Go on short road test like 3 blocks. See if you can see where oil is from. Extend road tests as needed.

There are 3 seals & the sprocket door gasket & its screws, plus splines of trans sprocket. Seal in sprocket door. Seal in tip of 5th gear snout near sprocket nut. Sprocket splines. Later sprocket/5th gear uses oring here. The sprocket seal itself. All can/will leak.

Unlikely motor is wet sumping. Road test bike at least 10-15 miles. Bring into garage, put on center stand. Remove primary oil filler plug. Using 1/4" dowel, rod or screwdriver, reach down behind chain & find bottom of primary case. Very easy to do. Oil will be about 1/2" on your makeshift "dip stick".
If motor sump is overfilling or the like, the primary oil will be too high. Way high like 1-2".

DO NOT put bike on center stand at all with motor running or it will add oil to primary very quickly. It just does.... Takes 10-20 miles to pump it back to frame. Of course this wouldn't normally matter. I put bike on side stand motor running often for quick restroom break. But.... you don't want to do that to test primary oil level.

The 2 small seals are the same part#. pretty easy to change. Pull seal from 5th gear using bent wire hook. Usually not tight. Sprocket seal can be a stinker. Very hard to pull. Tight going back in. Put sealant on sprocket splines, even if it has o-ring, they like to leak.

Several thousand miles ago I replace trans sprocket seal & the others. Factory had loctite on splines.... Worked good. I used silicon. Worked bad. Soon starting leaking from splines. I'd not thought it could pass that much oil by splines, but it sure did.

Don
Posted By: TinkererToo Re: TR7 leak - 03/23/21 9:14 am
'76 should have the groove in the mainshaft, and with the "O" ring and the lock washer fitted correctly (tangs facing outward) the splines SHOULD be sealed, as the ring sits at the base of the splines and is pressed up against the sprocket. That said, a little silicone can't hurt. Don's '73 is a different matter entirely.
Posted By: JoejBSA Re: TR7 leak - 03/23/21 3:28 pm
Don thanks for all this info , gives me some stuff to look at. One question I have is you had mentioned to not let bike run on the center stand or it will add oil quickly to primary ? I am guilty of starting and letting sit on center stand for a minute or two , also what makes it different from running on center stand as opposed to riding the bike in the straight upright position ?


Thanks again for all the info so far!
Posted By: TR7RVMan Re: TR7 leak - 03/24/21 12:59 am
Hi JoeBSA, I may have misspoke. It’s the side stand that raises primary oil.

Running on center stand is no problem.

Sorry if I caused confusion.
Don.
© Britbike forum