Hi all,
Did all Mk3 Commandos suffer from incorrectly hardened camshafts from the factory. How long did they last before they had to be replaced?
Should I assume that any Mk3 that hasn't had a replacement camshaft is going to need one?
Thanks,
Richard
Most Mk3s are still running…
- Log in to post comments
I disagree on this, i have a…
I disagree on this, i have a box with four of the original Mk3 cams all with worn lobe/s. One came out of Mitzi and the rest from clients Mk3 engines. Mileage on these engines varied but all failed before 50k, one failed at approx 6k. Another at 16k. Interestingly the engines didn't make any unusual noise that pointed towards cam failure. I found the failed cam on that 6k engine when starting to service the bike for the owner, turning the engine over when checking the valve clearances, i noticed one rocker wasn't moving as much as the others. Service abruptly ended and told the client that his cam was knackered. What does that mean he asked? 'An engine strip and spending money' i said.
On any commando it will be wise for a potential buyer to remove the rocker covers and turn the engine over while observing how much the rockers move, They should all move an equal amount, any that don't is indicating a worn cam. If the seller refuses to allow you to do this, walk away.
- Log in to post comments
Mk3 Cams
"Back in the day", an awful lot of Mk3s lost a cam lobe at under 12,000 miles. I'd say more did than didn't. A lot of the 1980s replacements weren't much better either.
They can run quite well at normal road speeds with most of a lobe (often drive-side exhaust) missing and of course there is no extra mechanical noise. If you're allowed to remove the magnetic drain plug though, there will usually be a "Christmas tree" on it after a run. All that metal has to go somewhere.
There have been magazine articles in the past suggesting that a cam failing will be marked by a frequent need to adjust the tappets but this is of course incorrect as the tappet clearance is set on the base circle. As Peter states, a visual comparison of rocker movements gives the clearest indication. There is usually one lobe far worse than the others.
If looking at a Mk3 with low mileage and no sign that it's ever been apart, I'd be budgeting for a look inside the gearbox and a replacement layshaft bearing too.
That said, all these things are fixable and the Commando is straightforward to work on. If you've had the fun of putting a bevel Ducati back together again then you'll enjoy working on the Commando.
- Log in to post comments
Hmmm, Just been researching…
Hmmm,
Just been researching what's involved to fit a replacement camshaft on a Mk3. That's more involved than I thought.
R
- Log in to post comments
Most Mk3s are still running the factory fitted camshaft. There were some soft cams and some sub-standard after-market replacements. Ashley Cutler has some information on this subject - something to talk to him about if you decide to look at his bike.
Build quality was variable throughout the Commando's lifetime but any that are in regular use today should be ok.