Bonneville America Forums Forums Technical Forums General Tech Engine casing replaced?

To anyone that may have had their casing replaced due to starter failure - got some new info. I have noticed increased oil usage since the repair and I'm certain it is being blown out through the crankcase breather hose. After two 500 mile trips, I drained oil from the plugged hoses under the bike and had to add a pint of oil.

My bike just got it's 4 year service and the dealer called Triumph about the oil/breather problem. The new crankcases (which my replacement is) do not have the rotary breather and seal like the original. The oil goes through a labyrinth in the case and oil is supposed to drop through holes and not get blown through the breather hose. Triumph suggested running my oil level at the minimum line or below as the engine may be wanting to seek it's own level. In essence, at higher oil pressures, the oil I'm adding is getting blown out. I find this confusing as it apparently isn't a problem with the new model bikes. Triumph claims the bike will not be harmed in any way even a quart low, so a pint low should be fine.

Anyway, the plan is to try running a lower level and measure usage. If there still is noticeable usage, it might be drainage problem in the crankcase which can be modified. I was curious if anyone else had noticed oil getting in the drainage tube. I've pulled the drain plugs and checked a number of times over the years and they were oily, but no oil ran out. After my last trip a bunch of clean oil ran out.

This problem not only would explain my oil usage, but also why my right spark plug is sometimes oily while the left is fine. The breather tube attaches behind the right carb. Any buildup could blowback into the carb.

Now, if you can run the bike and do no harm with 1 less quart of oil, why do they not just say put 3 quarts in to begin with? That doesn't seem right.

There must be something else that was changed in the newer models to accomodate the new cases. I always put in four quarts at oil change time, which if anything is slightly overfull. I have no noticeable oil loss between changes, now at about ~10K miles.

I know the bike shouldn't be using oil. Mine never did before the casing change. What I'm looking for is anyone that has a earlier bike that had a casing change due to starter failure. I agree that Triumph's response is lacking. At my dealers request I will comply and see what the usage is running at the bottom of the oil range.

Personally I wouldn't run mine low on oil but instead put up with some loss and keep it topped off.

I'll try running it right at the bottom line for awhile so I can give feedback to my dealer as to usage. BUT, throwing out a pint every 500 miles is a bit much to put up with. If it's still showing significant loss, they may try a mod on the crankcase to make it easier for the oil to stay in the crankcase. My guess is that's what will happen. Then I could keep the oil level in the normal range.