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Old 01-26-2015, 01:14 PM   #1
MATTY OP
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Hot --r 45 ?

I picked up a 1980 R45 about 6 months ago it had been sat for 20+ years has around 10. 000 miles on it from new.
I just got it mot tested and on the road last weekend, it was cold but i braved the weather and went for a good old blast to blow the cobwebs out of the old girl. The exhausts are in poor shape they seem to be rotten on the inside and its throwing bits of rust out and its a little louder on one side than the other but everything else seems fine with only one concern from me, the engine feels very hot, it is not running lean from what i can tell, and it is smooth running and brisk enough for a little engine.
Any ideas on the hot running, its my first BMW ever and not sure if they all run a bit warm or what.
IUts warmer than anything i have had before and i have had a great many bikes over the years, any advice because frankly its scaring me and last thing i want is a problem developing. It did 400 miles over the three days and its not showing any change in how it sounds performs etc just this heat issue. HELP!!!
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Old 01-26-2015, 02:09 PM   #2
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That's curious as the very last thing an R45 should do is run hot.

If you think about it give or take a few barrel fins an R45 has much the same cooling area as an R100 and yet it develops only half the power. If all is well it shouldn't run hot in the summer never mind the winter.

How did you diagnose it was running hot ? A quick measurement of the oil temperature after a ride might confirm if it's really hot. Normally it wouldn't even be up to temperature in the winter.
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Old 01-26-2015, 02:26 PM   #3
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Heaters

Heaters - in the winter the cylinders take on their 2nd roll as heaters for the rider - sound like it is working.

Seriously get a digital IR temp gauge to read the temperature of the cylinders - I have done on my bikes when running correctly and use it as a guideline for any problems but I don't have the normal temp reading on me now - maybe someone else will chime in with what is normal.

Temp gauge is also good for trailer wheel bearing / hubs
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Old 01-26-2015, 03:32 PM   #4
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It just feels to radiate heat more than anything i have had, it just seems hot i cant be more specific than that at this stage, it does tick when its cooling down and seems to do that more than other bikes too, maybe its just the fact the barrels are stuck outside the frame more or something, you have got me thinking now. I wondered if it is retarded on the ignition or something like that, its on points, i have not touched them other than a quick clean of the contacts it starts fine and apart from the exhausts which are basically history, and a little popping on overun i put down to the disintegrating exhausts i cant see how its running at all bad.
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Old 01-26-2015, 03:36 PM   #5
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Whenever I had a lean condition that made my temp go abnormal, my header pipes would glow enough to let me see (76 r90/6). If you're starting easily, revving well, and have a shortage of back pressure, I'd say maybe you're just feeling the radiant heat of some metal in front of you. Not to be contrary, but an r45 would likely hold heat for a lot longer than the r100, as there's a ton more cast iron in it and the bore is further from the cooling fins. Presuming a similar operating temperature, it should stay warm for a demonstrably longer time.
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Old 01-26-2015, 05:11 PM   #6
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This is a little off topic but you're the only person I know of that owns an R45!
Could you tell me what numbers are stamped on the side of your carbs? Would you take a picture of the carbs and how they connect to the heads?

Someone told me years ago that is the set-up you have to replicate to run CV carbs on an R60.

Thanks in advance!
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Old 01-27-2015, 03:27 AM   #7
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Quote:
Originally Posted by photorider View Post
This is a little off topic but you're the only person I know of that owns an R45!
Could you tell me what numbers are stamped on the side of your carbs? Would you take a picture of the carbs and how they connect to the heads?

Someone told me years ago that is the set-up you have to replicate to run CV carbs on an R60.

Thanks in advance!
Hi its got bing carbs
64/26/303 it is the 26 HP engine.
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Old 01-27-2015, 03:59 AM   #8
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35 Hp R45's use a few different model numbers 64/28/201 on the early bikes (Flatops) and 64/28/301 or 64/28/303, on the later dome tops.

The carbs attached to the heads in the usual way of Bing CV's and for the 35HP model the rubbers are the same as for 32mm Bing Cv's. The dimensions I have are 52mm OD x 43mm ID for the rubber and the head stub is 43mm OD x 36mm ID.
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190e screwed with this post 01-27-2015 at 04:24 AM
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Old 01-27-2015, 07:40 AM   #9
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Thank you!
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Old 01-27-2015, 08:02 AM   #10
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Excessive heat from an internal combustion engine may most certainly be do to the ignition timing. It's the first thing I think of. I'm an Old Fart and us older gear heads know this well.

You say you have ignition points? And you cleaned the contacts? That sounds like the problem right there. I'll try to make this as short as possible;

The ignition points fire at the moment of separation. While closed the points are charging the coils. The points have to be closed a certain amount of time to properly charge the coils. Not enough and you will get a weak spark. This amount of time that the points are closed is called dwell. We usually measure the dwell on our Airheads by setting the points gap. Do this with a feeler gauge. But it is only very accurate when the points are new. As the points wear there is a hill built on one side of the contacts and a valley on the other. Tiny little hill and valley sure. But because of this effect it is almost impossible to set the dwell using a feeler gauge on used points.

You can set the dwell using a Dwell Meter. But probably don't have one of those. A new set of points will be easier to set with a feeler gauge. Keep the contacts clean. Do not file them. The Tungsten coating on the contacts is not thick enough to file. (this may be done in emergencies but you will need new points shortly after doing this) Did you file the points? You now need a new set.

Once the gap or dwell of the ignition system is set the timing may be adjusted. You set the timing using a static test light to set idle timing and once this is set the full advance timing can be set using a strobe timing light.

Directions for setting the gap and adjusting the timing are in all of the manuals. If your bike seems to run OK right now except for this heat problem you may be able to set the timing without touching the gap. But there is an important concept about this system to understand. You can change the timing by setting the gap. But the dwell is not affected by changing the timing.
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Old 01-27-2015, 10:09 AM   #11
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Thanks for the advice i am on to this, will get new points right away.
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Old 01-27-2015, 05:57 PM   #12
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I spit on the heads. If water sizzles and boils off skittering, its too hot.

If it just sits there and smoulders without dancing like its on a hot skittle, its ok.

I can tell when its running really hot because it acts like crap. SLuggish and a little petulant. Rare, but rather obvious once it starts.

The headers of course are too hot to touch.

If its not pinging while youre riding it, I might check the timing, but wouldnt be too worried about it being super damaging.

The R45's sound cool I want to play with one.
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Old Yesterday, 12:38 AM   #13
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Its running temp range between 85 and 92 C . no idea what they generally run at, ordered the points yesterday should be here by the weekend.
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Old Yesterday, 02:29 AM   #14
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Those temperatures are fine but you must be riding it hard to get the oil temperature even to that level in the winter.

When you fit the points I recommend removing the bean can as it's so much easier to fit and gap them on the bench. It disturbs the timing but it's going to need resetting anyway. Once the points are fitted you'll find that fitting the outrigger bearing plate will change the gap so either allow for that by trial and error or adjust the points with the plate fitted which is easy enough on the bench but a pig with the bean can fitted. I then do a static time check on the flywheel S mark rotating the engine gently with plugs out using an Allen key in the rotor bolt. Some jog the engine over in gear by rotating the rear wheel but I've no idea how they do it that way and set the timing with any real precision. A strobe check at full advance should also be done as that's more important than the static timing. I find if static is set accurately the full advance is also spot on but you can't assume that as there maybe some wear in the advance mechanism.

If you are really fussy about the timing make sure to rotate the engine through several revolutions to check both cylinders are exactly the same timing. They won't be far out as the outrigger plate is supposed to ensure that but in practice there may be a couple of thou clearance between the plate and the bean can recess which allows for some adjustment.

Pic shows what the S mark should look like on the early heavy flywheel R65. The timing mark is the dot. You can just see the line above which is the OT mark for TDC.

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Old Yesterday, 03:51 AM   #15
MATTY OP
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Quote:
Originally Posted by 190e View Post
Those temperatures are fine but you must be riding it hard to get the oil temperature even to that level in the winter.

When you fit the points I recommend removing the bean can as it's so much easier to fit and gap them on the bench. It disturbs the timing but it's going to need resetting anyway. Once the points are fitted you'll find that fitting the outrigger bearing plate will change the gap so either allow for that by trial and error or adjust the points with the plate fitted which is easy enough on the bench but a pig with the bean can fitted. I then do a static time check on the flywheel S mark rotating the engine gently with plugs out using an Allen key in the rotor bolt. Some jog the engine over in gear by rotating the rear wheel but I've no idea how they do it that way and set the timing with any real precision. A strobe check at full advance should also be done as that's more important than the static timing. I find if static is set accurately the full advance is also spot on but you can't assume that as there maybe some wear in the advance mechanism.

If you are really fussy about the timing make sure to rotate the engine through several revolutions to check both cylinders are exactly the same timing. They won't be far out as the outrigger plate is supposed to ensure that but in practice there may be a couple of thou clearance between the plate and the bean can recess which allows for some adjustment.

Pic shows what the S mark should look like on the early heavy flywheel R65. The timing mark is the dot. You can just see the line above which is the OT mark for TDC.

OH it is winter here let me tell you, I rode it like i stole it to get it to those temps in the dark too over the Lammermuir Hills that gets anything hot thrashing them over there.
Thanks for the advice i will be taking my time getting the timing set accurately, and i need to look at getting some exhausts.
A friend down south has a pair of old norton comando exhaust pipes i can have they are apparently in decent condition, not sure what they would be like on the little R45 .
With an exhaust swap in mind are other jets still available for these Bing carbs or are they tough to find. and any advice on jetting i have zero experience with these carbs or BMWs.
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