The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: roryjohnson on November 29, 2010, 05:22:01 PM
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Hello Everybody
My name is Rory, I just bought my first BMW R65 1980, very happy with it! However, Im a bit worried about the fuel consumption. My first tank full of regular unleaded ~13 litres only got me 150km, riding in the city and one long excursion at ~ 100km/h with a passenger.
Is this the normal consumption??
Also - Im finding it pretty tough to get started in the morning. It seems to get flooded quite easily, takes ages to start, and then tries to conk out when i stop at the traffic lights, unless I keep giving a little gas. Any suggestions / tips etc?
Thanks! happy to "meet" you all
Rory
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Welcome Rory, I'd suspect the carbs need looking at, any idea if the previous owners performed any maintenance on the bike .
The bike's 31 years old and a good chance that nothings been done to them .
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Does it have an LS front end? Twin disc's. :)
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Nice LSU hoodie! I as well would suspect that the carbs need a rebuild or a balancing. Are you using the choke with throttle as that seems to cause problems. Beautiful bike ya got there.
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Nice bike. Re your fuel consumption, keep in mind only half the gas tank feed the carbs! The other side never drains. I think BMW made some lame excuse about it being an emergency reserve. Ha ha. As far as starting goes, I usually put it on full choke and crank it with no throttle to prevent flooding. After it starts, I let it run for about 15 seconds and then pull it back to half choke. Still no hand throttle. Ride normally for a block or two and then turn off the choke. Air cooled engines tend to be a little cold blooded...
Of course a good tune up and carb balance is a good idea.
Steve
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Regarding the hard starting, it sounds like your valves need adjusting. If you haven't done so since buying the machine, do it before riding another kilometer.
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I usually put it on full choke and crank it with no throttle to prevent flooding. After it starts, I let it run for about 15 seconds and then pull it back to half choke. Still no hand throttle. Ride normally for a block or two and then turn off the choke. Steve
Works for me. :)
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Welcome Rory,
Nice looking bike.
Not being able to think in km and litres I converted your numbers to 32.6 MPG Imp which is not too good.
You should get 50MPG imp or more on a decent run as long as your not flat out all the time so as others have said the carbs probably need looking at.
As well as a general clean I would check that the jet sizes and settings are stock, replace the O rings and carefully inspect the needles/needle jets which are known to wear.
As for starting in cold weathers most owners need full choke to start then back off to half choke as soon as it fires then off altogether pretty soon after. It s normal to need to hold the revs up with the throttle until the engine is warmed up, say at least a couple of km. There would be something wrong if it would idle straight after a cold start.
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Dear All
Thanks a lot for all these helpful comments and suggestions, I'm going to take it to my local and have the carbs checked out.
As far as I know, the guy I bought it off more or less took the whole bike to pieces and rebuilt it, after a long stink in someones garden/garage. He seemed to know pretty well what he was doing, however he didnt mention if he had worked on the carbs.
Thanks and nice to meet you all!
Rory
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My bike is close to reserve around 225kms sometimes 210, sometimes 265kms out of a tank on my 1981 R65. I run premium unleaded which in Oz is 94/95 RON.
John
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~45 mpg (US gallon) is normal for stock tuned R65.
IT sounds like it is definitely time to adjust the valves, install new plugs and checkout the carbs (also check that the air filter is clean).
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I get the impression it's running fine once warmed up?
That being the case, the o-rings are probably fine, but the main jet atomizer could be plugged up.
I'd also suspect the floats are getting heavy, allowing the fuel level to ride high. As a quick check, pull a float bowl and measure the fuel height - it should be about 12mm from the top edge.
And the third item to check would be the slide needle and needle jet - the two rub against each other and over time the orifice enlarges and the needle gets smaller allowing much more fuel to flow. You can't really tell by eyeballing, either measure or replace.
By the way - beautiful bike! It looks just like one I sold a couple years ago (and still miss).
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~45 mpg (US gallon) is normal for stock tuned R65.
IT sounds like it is definitely time to adjust the valves, install new plugs and checkout the carbs (also check that the air filter is clean).
I recall the thread .."Post your mileage" and for what ever reason the UK bikes were all returning 50+ mpg i know theres a difference between US and Imperial gallons but not enough to explain the variance.
That said if you dont know the history of the bike i would definitely do the valve clearances rebuild the carbs and check the timing (is it electronic ??) a set of points and plugs wouldnt go amiss also change all the fluids.I bet Barcelona is quite nice if you need a hand i will pop over, if they ever get the snow off the runways that is...
BTW nice scooter.
Lou
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Rory I see your bike has the flat-top Bings. I've run my 79 on both flat-tops and dome-tops, both apparently in good condition and correctly set up, and found the flat-tops gave consistently better fuel mileage. Don''t know why.
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Imp gallons are almost exactly 20 % bigger than US gallons so it's easy to convert US MPG to Imp MPG by just adding 20% :-
40 MPG US = 48 MPG Imp
45 MPG US = 54 MPG Imp
50 MPG US = 60 MPG Imp
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Thanks Barry both Pete (the Admiral) and i are regularly doing nearly 60 mpg but that is with flat tops didnt realise there was such a big differance between a US gallon and an Imperial one, That makes price of gas almost reasonable here..... [smiley=cheesy.gif]
Lou
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"Imperial" gallon has a slightly colonialist sound, doesn't it? Over here the US gallon is sometimes called the Queen Anne gallon, which gives an idea of when the two became different sizes. Anne died in 1714 I believe. She gave her name to loads of other things too: QA architecture, QA fashions, QA furniture. And during her time she was sometimes called Brandy Anne, though maybe not to her face.
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Hi Rory,
Nice R65! Do a full tune-up and be prepared to go through the carbs. Ask you questions here but you are not the first to disassemble the Flat-Top carbs. Do some searching/reading about replacing the diaphrams, checking the chokes, torquing the heads and setting the valves and timing. On an older bike you will probably have to replace the needle jet and needles to get you mileage back to normal but there are many things to check first.
When you get to something you don't understand --- ASK! We have been there and are quite willing to help.
The only dumb question is the one not asked!
Do all that and then you can contemplate your first spline lube...
Welcome!
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When my 1984 R65 was relatively new, I used to get 17km/litre in urban riding and 20km/litre highway riding.
Carrying my 5'11" (1.8m) girlfriend as pillion generally reduced these figures by about 3km/litre.
These figures were pretty reliable and repeatable.
The best we ever saw was about 24km/litre on a highway ride two up, keeping to about 80km/h to allow a friend who was learning on his 250 to keep up.
Twenty years later I rarely if ever carry a pillion, the bike could do with some tuning, and I seem to get about 14km/litre.
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When my 1984 R65 was relatively new, I used to get 17km/litre in urban riding
OK
multiply 17 by 4.546 that's 77.3 km per Imp gallon
multiply 77.3 by O.62137 that's 48 Imp MPG
add 20% to 48 and that's 57.6 US MPG
Only now do I understand you were getting good mileage !
No offence to Aussie members - how come you guys gave up on good old miles. Litres I can understand
(but I love the US for not going metric).
km just makes the whole thing far too difficult for mental conversion.
Forgive me - I've spent a confused life doing mental arithmetic ever since being taught Woodwork at school in Imperial units and in the next lesson Metalwork in metric units.
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Forgive me - I've spent a confused life doing mental arithmetic ever since being taught Woodwork at school in Imperial units and in the next lesson Metalwork in metric units.
Barry - I'm glad YOU'RE doing the math here! Thanks for the clarification.
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No offence to Aussie members - how come you guys gave up on good old miles. Litres I can understand
(but I love the US for not going metric).
km just makes the whole thing far too difficult for mental conversion.
Forgive me - I've spent a confused life doing mental arithmetic ever since being taught Woodwork at school in Imperial units and in the next lesson Metalwork in metric units.
A) I was born in Cheshire, not Australia.
B) I was educated in Australia in both imperial and metric, so as you too should be, I am bilingual.
C) Have you ever tried doing physics or engineering in imperial units? Why on earth would anyone want to stick with imperial units?
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Have you ever tried doing physics or engineering in imperial units? Why on earth would anyone want to stick with imperial units?
I am an Engineer and you're quite right of course ... I was being a bit tongue in cheek.
I like to use old units on an old bike and if the UK ever changes to km (which it won't) I'll still be working out fuel consumption in MPG.
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When my 1984 R65 was relatively new, I used to get 17km/litre in urban riding
OK
multiply 17 by 4.546 that's 77.3 km per Imp gallon
multiply 77.3 by O.62137 that's 48 Imp MPG
add 20% to 48 and that's 57.6 US MPG
just makes the whole thing far too difficult for mental conversion.
Barry i just took my shoes and socks of to work this out...surely you deduct 20% for USG as USG are smaller than Imperial ????
Lou
Thread direction......sorry
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Well spotted Lou.
I need to do a u turn(http://)
In fact it's divide 48 Imp MPG by 1.2 to give 40 US MPG
in which case 17 km/litre is ok but not so hot
See how confusing it is. [smiley=dizzy2.gif]