R45 Timing marks

[mrfandangle]

HI all.After some help please. Changed from points to electronic ignition on my 1980 R45. Much to my embarrassment I have never had to time an engine before..........Problem I have is this.

I cannot find/see any timing marks that tie up with the manual. (the S for retarded/Z for advanced) when adjusting the timing using a strobe light.

In the BMW manual and Haynes it shows the letters as being upright, I think I can see the S but its at 90degs to what is suggested in the manual i.e laying flat but this could be wishful thinking........

Fortunately I marked the bean can before I took it off so I have a datum to work from I think unless the timing needs to be different with the electronic ignition?

There is a couple of white marks on the flywheel but they are quite close together but again do not appear to correspond with anything.

The bike starts and idles nicely but does seem a bit flatter than before, again could just be my over sensitivity and thinking something is wrong.

Many thanks

Glen

 

[mikeyboy]

R45/65 bikes have a different flywheel from the bigger bikes,the marks are quite difficult to see,
Take a plug out and get it to tdc,hopefully you will be able to see the marks which are a bit further forward on the flywheel,and can highlight them with paint.
I have a 65 flywheel at the workshop which I could photograph if you need.
But not till Monday

 

[mrfandangle]

Hi Mikeyboy.
Thank you for the reply. I have now done as you have suggested. One of the White paint marks corresponds to TDC. Do I use this for tickover timing or full advanced 3500rpm?

 

[mikeyboy]

I’d need to check the actual spec for a 45 but iirc timing should be 6deg btcd,so there should be another mark just in front of tdc mark,plus another for full advance at 32deg btdc .
So unless you have a posh fully adjustable timing light ,you will need to find the other marks.
If the marks have just been painted on its highly possible that the flywheel has been fitted in the wrong position.

 

[mikeyboy]

If it turns out the flywheel is on wrong,you could just set the timing by ear,
Get the bike to idle nicely then advance the bean can till the idle increases as high as it will go,
Road test the bike and retard the timing if it pinks under load.
Not ideal but will save removing the gearbox

 

[mrfandangle]

I’d need to check the actual spec for a 45 but iirc timing should be 6deg btcd,so there should be another mark just in front of tdc mark,plus another for full advance at 32deg btdc .
So unless you have a posh fully adjustable timing light ,you will need to find the other marks.
If the marks have just been painted on its highly possible that the flywheel has been fitted in the wrong position.

This is what I was thinking in regards to the flywheel.

The paint marks are in the timing window with the can in the same position as when it had points,using the timing light, at tickover.

I have had a good look at the flywheel when turning it over by hand and cannot see anything at all really in regards to timing marks, only the painted marks.

They are are quite close together and near a machined depression (very shallow blind hole) in the flywheel.

Its a Boyer Bransden ignition I have fitted.

Your memory serves you well It is 6deg bTDC

Thanks for your support so far

 

[mrfandangle]

I could use a timing disk as long as I know how many degrees full advance is??

 

[mikeyboy]

6deg plus 26 deg advance
32deg

 

[mrfandangle]

Many thanks Mikeyboy. Disk on order and white paint at the ready.