BMWMCCWA

Hi guysI'm new and have just got a '76 R90/6 wich has not been used for the last 20 years Lovely condition as its been out of the elements. However, it wont start as I've not got any sparks & try as I might I cannot time the motor statically.

The floats are obviously old but are at the correct height and the petrol enters the carbs. The bowls are clean & the airways have been blown through
The spark plugs have been changd twice & are new. The plug wires are intact Zero, ohms whem tested but are old. The contacts have been cleeaned & set at 35mm. The condenser is origional but should not affect starting. The coils are the 6volt in parallel(?) & origional.
When I put the light from the condenser to earth & turn the motor clockwise
a. There are no sparks.
b. It seems that I cannot get the light to go out or even flicker when the middle 111 with the S is in line with the timing mark on the crancase
Also Im thinking very seriously of installing an electronic ignition so can you pls advise me?
Im obviously doing something wrong and will appreciate any advice or help

Cheers
10morris

hi /6s if it has the old spark plug leeds with the steel tops sometimes they were bad for stuffing up.Coils i used 2 6 volt VW beetle coils they worked in my 90s ok.They are alot cheaper than bmw ones.First i would check the kill switch and ignition switch and conections sounds it might be corrosion in a connector or a bad earth somewhere having sat for so long.I am no sparke but had a bit to do with the old 6s and 7s.hope you work it out Goldie

Hi 10morris - I'm no R bike expert, but herding electrons is my business... Sounds like you've covered the basic tune, but something more fundamental is wrong. Now you get to check everything... you'll probably need to find at least a test lamp or voltmeter (best) to get anywhere, though I'm sure some of the older guys may have better hints as to what's more likely to fail. Here, from easy to harder, are some things to check:
- are the grounds all really there (watch for oxidized/corroded/loose screws, missing wires...)?
- is there battery voltage on the coil primaries (the low voltage side)? no volts, no sparks...
- are the points actually closing & opening as you turn the motor? Is the connection/wire from the coil to the points intact? The spark is generated when the contacts break, so the circuit must go from continuous to open. Sounds like the gap is set ok, but check that they close & make good contact as well - if things are bent or worn, or the contact faces aren't meeting correctly, you won't get the proper operation.
By the way, the condenser IS critical - if it is either open or shorted, or in any way not a capacitor, no spark. Back when I used to try to make british sports cars work, that was usually the first thing we replaced, as it was hard to test and they frequently dried out & died.
I'd need a wiring diagram to make any further headway, so I'll shut up & let the wiser heads advise further!
There is a way to do a static tune even without a real spark, close enough to get it to start, just by finding TDC on the compression stroke, moving back ~10 degrees (or whatever the timing spec for the motor is) and setting the points to just open at that point - it won't be right, but it should make noise anyway. At least you'd be in the ballpark...
If anyone is interested, there is an exhaustive discussion of the airhead ignition (& static timing the right way) at this site: <http://bmwmotorcycletech.info/ignitiontheory.htm>
Electronic ignitions are a wonder for old motors - away go all the fussy bits that wear out (most people never even open the K ignition units) - but which one to get is another question.
Good luck -
mark

Hi 10Morris, I think I might have a workshop manual that will include the R90/6, I will have to look for it as since we moved here it has not been used. Should you need to use it for awhile you can PM me then we can arrange to meet up somewhere, perhaps I can also give you some info on what to look for (note I am no expert, but have always seemed to be able to sort my problems out).
Regards Geolero

Hi 10Morris

What has transpired?

It sounds like your points are not opening?? Did you remember to refit the advance mechanism after moving the points base?
Or the points wire is touching the casing, upstream of the condensor.
90/6's don't deserve to remain parked up.

John

Guys Thank you very much for your interest and very valuable tips & offers of help. I got some new parts..Condenser/points/spark plug wires/floats & have installed them. Excellent spark, the coils are good on testing. I got it to fire once ...but domestity intruded & I got rushed. Instead of retarding the ignition I advanced it...Anticlockwise is ADVANCE. Of course it would'nt fire after that. I then had to do my domestic duties. That night I awoke in a sweat & could'nt sleep after I realised what I'd done.Duh! Anyway ever since work has intruded. I'm salivating to get back to get the motor fired up & hear it burble.
Probably a good job that I didnt get the motor going as the petrol hoses are perished and pi..ing out petrol onto the exhaust pipes. Got some new ones to put on before i try again.
What a lovely thought out machine. Should have got one decades ago.
Cheers & thank you all again 10morris (Ralph)

Hi Guys, It Starts! Runs beautifully, very smooth & quiet. Just had to take it round the block (A very small one). Now to get on with the rest of the recommisioning.
Thanks again for your interest & help. Must see you at the Club meeting.
Cheers, 10morris

Now now, if you carry on like that, everybody will want one! Bring it along to Catalanos tomorrow and we can all look at it!

John

The reason why my first trial run was so small is that Ive not got brakes! Yet. 10 morris

G'day 10 morris,
I fitted a Lumenition MCK 500 electronic ignition kit (English manufacture) to my 90/6 in December 1980 - best thing i ever did to it. Instant cold starting, and no maintenance. I recall timing it once since, and changing the plugs a couple of times. (I suspect neither was actually necessary though!) It's ridden regularly but several weeks can easily go pass between rides - it still starts instantly.
Cheers,
David King.

Hi David,
Thanks for your advice with my ignition. It certainly sounds a good idea.........But, I'm interested in your opinion as to how far I should go in 'restoring' my bike. I have several second hand vehicles all of which I use regularly for work and play. I am loath to change them too much as I look on myself as a custodian rather than on owner.
For instance I have tried to get the decades of stain and grime off the bike's engine covers without success. I've tried degreaser, mag cleaner with a tooth brush & swearing but without resorting to bead blasting I dont know what to do. I dont want a show queen that I will be loathed to use but a presentable bike with patina. And the same thing pertains to electronic ignition. You and I certainly think E. ignition is a good thing but I wonder what the general opinion will be?
Also, has anybody got some good ideas about the gear change. I shudder every time I change up in the lower gears, altho' I 'feel' my way into the change & wait for the revs to fall. Those poor gears must take a thrashing. The changes are sweet when the oil is cold but accompanied with a clash not a clonk when hot. The oil is as recomended and the idle is just below 1000. Every time I change gears I hear a whistling noise from the clutch area. Any ideas guys?
Anybody got some good ideas about cleaning the engine covers?
Cheers
10 Morris

Hello Morris,

Try oven cleaner- you will need to spend some time cruising the isles at coles / woolworths for a NON Caustic cleaner, and obviously try a small area first, I have used coles Reliant product to clean up model airplane engines with reasonable sucess.

Regards
Graeme / Cookie

How far to go in restoring a 34 year old bike could get you into a quandary real quick. I've owned mine since 1977, and being an 'if it ain't broke, don't fix it' sort its covered in patina/character. I like this as it can be seen as a measure of my last 30 odd years.
Over the years I've used everything from expensive pots of goop+tooth brushes+swearing to serious steam cleaners. Currently it's a good lather with degreaser+ the engine bay cleaner at the local carwash+ hit the shiny bits with chrome polish and the black non metallic bit with armorall, and it actually comes up pretty good.
Try this for an interesting read:
http:www.ibmwr.org/r-tech/airheads/R90_rebuild.shtml

Regards.
David King