Hi there

As I wrote in another post elsewhere on this site, I own a 1983 BMW r80 G/S, and am currently in the throes of fettling her with a mind to get back on the road. A thought struck me the other day...the last time I filled her up it was with 4-star, which was widely available at the time, with unleaded being an alternative.

Now, I've never used owt but 4-star in her and just wondered what the situation was now.  I do seem to recall a bike mechanic buddy at the time telling me that as unleaded was used in Europe, the BM's were designed to run on it.

So, could anyone shed some light upon this, please; t'would be a pity indeed to do some avoidable damage to the motor after keeping the bike all this time.

Thanks in advance.

Y'all ride safe now

DM                                                                                                                                                                              

Sadly for you that model was designed to run on unleaded in 85 so it's either use an additive or get the work done to allow it to run unleaded. Also watch out for that bloody ethanol they stick in the petrol these days. It plays havoc with older bikes as I know to my cost.  

I had a couple of old airhead BMWs that needed leaded petrol or LRP. When four-start all but vanished, I made inquiries and the general feeling was that as long as you didn't thrash the bike, and as long as you checked the valve clearances often, you'd probably be OK.
Otherwise, as Gloom says, either use an additive or have the valve seats replaced. At least removing the heads from airheads is a pretty easy task, so you can just pass the heads over to your local engineering workshop and do the rest of the spanner work yourself.
Motorworks in Huddersfield used to offer an exchange service for reconditioned heads that included new hardened valve seats - might be worth having a word with them.

                                                                                                                                                                             

Thanks guys :)  I ain't much into thrashing my bikes these days, but as I remember, part of the fun of the early G/S was it's nippy acceleration...so, I might have a chat with Motorworks, or buy some 'snake oil'additive 

Thanks again for your responses

Ride safe

DM                                                                                                                                                                              

Up until two years or so back I ran a selection of mostly classics, Mostly Harleys and Brits. I never bothered with all the tosh that was bandied around about valve seat recession, I just stuck unleaded in and had no problems. I didn't change my riding style either, in fact I tuned one Norton single which then got me 90+mph from a bike that was originally road tested at around 80 back in the fifties.
I read one article arguing that the hammering that valve seats take in their normal lives work hardens them so they won't recede due to no longer having lead in their pencil, so to speak.
I don't really know enough to make any kind of technical argument either way, but can only tell you that I rode my BSA, Triumphs and Nortons as they were designed to be be riden and they suffered no valve damage, except when I bent one through over revving.
My gut feeling is that there were some people making a lot of money out of stoking the fears of classic bikers a few years back.

                                                                                                                                                                             

The top n bottom of it is that it does not matter what petrol you put in it in the UK. However be very careful because it needs to be BSEN rated fuel as some, Morrisions and ASDA I think, are mixing it with bio ethanol and that is not good                                                                                                                                                                             

OK...thanks for the advice guys  As Wills pointed out above, it is no real biggy to get the heads off...so I might just suck it and see, as it were.  This first year, I won't be going too far afield on her, and I can check things out over the winter before making an executive decision about it...at £210 each from Motorworks, recon heads with new valve guides might be expensive, but tempting if I'm considering a European trip in 2014

Thanks for that bit of advice about bio-ethanol in Morrison's/Safeways fuel, AJP                                                                                                                                                                              

Hi Dingus.....I have been using the CAT for many years now and find them good. If you read the spiel on the various web sites you will see what they do. They were invented in WW11 days for the Merlin Engine for when lead was needed for ammunition and scarce for petrol, I have used them in petrol and diesel engines and transforms them, smoother and more mpg. I have only used the tube type where the petrol go in one end `1/4" tube` and then feeds the carb from the other end `1/4"`tube, the ones that I have used are about 6"/8" long + 1" Dia with the hose tails on the end......I do not know where you would mount this, I could only suggest it under the tank with tie raps.
www.fuelcat.co.uk/? or www.carburetters.co.uk/Fuelcat.php?
or google search fuel cats.
best of luck Cros 

                                                                                                                                                                             

Hi Dingus, I found this type as I was browsing eBay, it is the type you put into your tank to produce positive or negative irons in your fuel. I said in my previous statement that I only used the tube type but I remember using this other type that you drop in the tank in my first R1150RT  year 2004 although I would not use it for leading purpose, I have used it for economy,smoothing and piece of mind.

http://www.ebay.co.uk/itm/Vintage-Classic-MBK-Scooters-...484ad59f8e

Cros asin Bing                                                                                                                                                                              

Thanks for that Bing...an interesting link and looks fairly good.  Didn't see your post until today, by the way    

Not sure about mounting anything under the tank etc, and would prefer an inline version.  Might research the more recent product as advertised in ebay.

Thanks for your input, mate 

Anyone else out there in BM land have any experience of this?

Cheers

DM ;)