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Kelvin
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R65LS

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"New" bike
10/08/19 at 02:41:52
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G'day,

I've been lurking here for some time, I didn't put up an initial post because I was unsure of where to put it.

However, I recently picked up a second bike so perhaps now is a good time to introduce myself?

I rode an R65LS in the 1980s when I was a uni student. Financial constraints required that I do all the work on it myself. Although I had a number of other bikes after that I was looking for a bike in 1996 and found one identical to the one I'd sold in 1988. Recently I found another, slightly newer, bike, this one with 135k km on the clock and many of the mods necessary for bikes of this age (SS pipes, SS brake lines...) and what I thought was a reasonable price (AUD 6,100). I've just gone though the process of getting it from Melbourne to Sydney and fixing a few minor issues.

It had a major issue with carburetion, not functioning properly above 4k revs and not at all above 5k (but beautifully below 4k). As is usual I was able to fix this with considerable help from the historic threads on this forum: many thanks for this!

Both bikes are on historic (club) rego, so I get 60 ride days per year. This is two rides per week with the pair of bikes. They're running with only minor differences at present. I live in NW Sydney, so fairly regularly ride north up the old Pacific Highway and west to the Putty Road.

Cheers,

Kelvin

  

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1983 R65LS 1985 to 1988
1983 R65LS 1996 to present.
1984 R65LS 2019 to present.
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skippyc
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Shouldn't have sold them
old bikes.

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Re: "New" bike
Reply #1 - 10/08/19 at 17:26:53
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Nice looking bikes Twin, twins
  
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ged in oz
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Re: "New" bike
Reply #2 - 10/09/19 at 03:45:06
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Nice work Kelvin. You’re spoilt for choice.

What was the issue with the carbs?

  
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Kelvin
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R65LS

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Re: "New" bike
Reply #3 - 10/13/19 at 05:13:28
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Dismantling showed that one of the needles was corroded, and the springs were old/rough/corroded. I replaced the needles, needle jets and springs and got a bike that functioned above 5k but not below. After some reading and substitution I have it running happily with the new components but the needles raised two notches to position 4 (original was position 2, my Haynes manual and the BMW workshop manual say position 3).

With the needle in position 3 the bike idled and worked above 5k, but 3k to 5k it would lag when the throttle was wound on. It would accelerate, but it would pause first.

There was a bit of crud in one of the main jets, and although the carbs had recently been serviced (and the outsides were beautifully clean) the main jets were stuck to the main jet holders: I think the carbs were serviced but not completely disassembled. I'm not entirely sure that the whole saga was not caused by that tiny bit of crud.

It's also possible that the needle was dropped to position 2 during the recent service by mistake, and that this wasn't picked up because the bike was not ridden at highway speeds after the work.
  

1983 R65LS 1985 to 1988
1983 R65LS 1996 to present.
1984 R65LS 2019 to present.
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Barry
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Re: "New" bike
Reply #4 - 10/13/19 at 06:05:56
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Kelvin wrote on 10/13/19 at 05:13:28:
With the needle in position 3 the bike idled and worked above 5k, but 3k to 5k it would lag when the throttle was wound on. It would accelerate, but it would pause first.


Assuming float levels are correct that's a sure sign that it's running weak at position 3.  One needle position is a very big change though. Another option is to go one size up on the needle jets which is much smaller change.

When you consider these bikes were set up relatively weak by the factory and then if there is any ethanol in the fuel it will make them run even weaker, it's no surprise that the mixture is marginal at the book settings.
  

Barry Cheshire, England 79 R45
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Bob_Roller
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Re: "New" bike
Reply #5 - 10/13/19 at 12:34:49
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Do you have any idea what work was done, parts replaced when the carbs were worked on ??

Sounds a bit like a tear or hole in a carb diaphragm .
  

'81 R65
'82 R65 LS  
'84 R65 LS
'87 Moto Guzzi V65 Lario
'02 R1150R
Riding all year long since 1993 .
I'll give up my R65, when they pry my cold dead hands from the handlebars !!!!!
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Kelvin
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R65LS

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Re: "New" bike
Reply #6 - 10/15/19 at 00:12:40
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The recent carburettor job was to replace the O-rings and clean, my guess is that the diaphragms were not replaced. They're fine at the moment.

The needle jets are the correct size as per the book, so I'm not in a hurry to replace them. As it stands at the moment the bike is running sweetly, but rougher than I can usually get it. I'm going to run a few tanks through it and see if it settles down. I want to see what sort of fuel economy it gets and also confirm the needle configuration of the other LS.

Fortunately we're just coming into summer in Oz... Smiley
  

1983 R65LS 1985 to 1988
1983 R65LS 1996 to present.
1984 R65LS 2019 to present.
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Kelvin
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R65LS

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Location: Sydney, Australia
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Re: "New" bike
Reply #7 - 10/31/19 at 01:21:56
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Quote:
my guess is that the diaphragms were not replaced.


Or perhaps not. RHS diaphragm was not oriented correctly, so the piston was 30 degrees out. I now think that the PO replaced the diaphragms, but (very) inattentively. No wonder I had difficulty tuning it.

I'm currently working through a problem with fuel dripping out of the LHS float chamber while I'm riding it. I replaced the float needle, to no avail. Current hypothesis is that corrosion on the spring clip caused it to jam, I should receive a pair of these tomorrow (and I should've replaced the $2 items when I did the float needles!).

  

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1983 R65LS 1985 to 1988
1983 R65LS 1996 to present.
1984 R65LS 2019 to present.
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ged in oz
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Re: "New" bike
Reply #8 - 10/31/19 at 16:32:41
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Ewww. A CV carb is not going to enjoy that!

The diaphragm installation doesn’t give a lot of confidence in the previous carb rebuild. I suspect it warrants double checking everything, particularly float heights. That might expose the source of your leak too.

Little by little Kelvin.
  
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