Cam timing marks on Tenere

[luadraman]

Hi guys, had a bit of a major malfunction on my 34L requiring engine to be taken apart and back together again but having trouble sorting the timing. This is totally new to me and I'm pretty remote in Niger with a non-English speaking mechanic!

From what I can tell, at TDC I should be able to see timing marks on the cam sproket and flywheel through the access screw holes. The cam sproket mark is the dimple? I can't see anything else on it. The flywheel has me confused though - I can see a circle with a vertical line through it (possibly a little screw), the letter 'H', and then the letters 'IT'. Which should I be going for?

Also on another post I read the engine turns anti-clockwise, does this mean the flywheel spins anti-clockwise when the engine is running?

Thanks a mil guys.

[dblunn]

Hi there,
when looking through the little hole on the left hand engine cover (over the flywheel) and rotating the crank anti clockwise you will see the first mark which is the full advanced timing mark then a bit further on you see the idle advance timing mark (I think these corespond to 36 degrees and 12 degrees btdc) then you will see the mark which has a small T next to it and this signifes Top Dead Centre. You can confirm this by puting a (softish) rod down the spark plug hole and feeling for the highest point of the piston travel.

Clean the two bolts and the threaded holes of the cam shft with a degreaser (like carby cleaner or laquer thinners)

Now up the top end you put the cam shaft in with the lobes facing down (ie TDC on compression stroke, all valves closed). Now fit the top cam sprocket so that:

1. the left (front of bike) side is tight and the rear or rhs is slack (this is taken up by the tensioner.

2. the two lines on the sprocket are level with the top surface of the head (there will be one of the two bolt holes lining up with the one on the cam shft), there are two possible ways of doing this and both will work fine but to be a purist the half with the dimple up will serve as an indication that you are on the comression stroke (just in case you didn't notice the position of the lobes).

If the lines on the spocket don't line up drop the sprocket and move it to the next position on the chain. Depending on the wear on the cam chain they may not line up perfectly but the sprocket only moves in increments of chain links so there is only one best fit.

Put some strong thread locking loctite (something like 277) on the bolt thread and do the first one up finger tight. Rotate the crank 360 degrees so you can get at the second hole and do the same but torque this one up then rotate the crank again and torque the first one up. Depending on the book I have seen between 10 and 22 Nm torque for these bolts, I split the difference and used 15Nm.

You can also put a little grease on the bearing surfaces of the cam before you put it in. Make sure the mating surfaces are clean and oil free before you apply some 3-bond gasket goop.

Hope this helps, Dave

[luadraman]

Thanks, that helps loads - nice clear explanation. My Niger mechanic had it back together by the time I saw the reply though! Runs perfect except for some popping in decceleration, don't know if that's the timing slightly off or something else... I know how to set it next time though. Which leaves me one question - what the hell is that little screw-out view hole in the cylinder head for? The dimple at that point corresponds to what???

[chucky55]

This is to allow the install/removal of the rocker shaft in the rocker cover.

Cheers from Oz

[Dick]

Hey Luadraman

Have you got a blog or website ??

I feel the need to see a few pictures of an old 34L (King of Bikes incidentally) being fixed up in a remote part of Niger in a back street garage by some bush mechanic for 20 quid, with the engine in a million bits, just before the bloke puts it all back together and it runs sweet as a nut.

Just how adventure motorcyling should be. Happy days I bet

Cheers

Dick

[luadraman]

@ Dick Here's my poor engine in the hands of two butchers:

I watched in agony as they tried to get the flywheel off with a screwdriver and hammer. When one guy was sent to get the proper tool he returned with a second bigger screwdriver so they could both go at it. Getting it back together was another barrel of laughs. Two days of head scratching, taking apart and putting back together again? I eventually went off to have a drink to calm myself and returned to find they had set fire to the bike! I put the lot on a truck the next day and got out of there!


P.S. Here's a pic of the flywheel and those timing marks for any future searchers (note the dents from bush mechanics), I'll up a pic of the camshaft next time I'm looking at it - hopefully not anytime soon.

[bacardi23]

oh dear god! I can't stop laughing with that "proper tool" lol

I'm sorry for your engine...

hope you get it fixed soon!


Vando