Gearbox Temperature

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Norman_John
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Gearbox Temperature

Post by Norman_John » Sun Sep 15, 2019 8:12 am

Good morning folks,
When my fancy ignition failed I parked the B44 at the back of the shed to let it think about the shame. For four years.
Last week I finally fitted the Pazon, changed its juices and got it mot’d. :ban
Apart from deciding to drip oil in revenge after an hours run through the lanes I notice that the gearbox is getting hot, as in if you hold your hand on it the casing it would burn (so 70-80 degrees?).
I know the C15 based gearbox is quite stressed, but do others find the same?

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SteveS
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Re: Gearbox Temperature

Post by SteveS » Sun Sep 15, 2019 10:51 am

Hi

Somethings amiss. Maybe something has partially seized over time? I guess you have already checked the condition of the oil for any tell tale particles and checked the level is correct.

Hope the solution is straight forward

Regards Steve
Steve Sewell

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Re: Gearbox Temperature

Post by Norman_John » Sun Sep 15, 2019 1:40 pm

Hi Steve,
Yes agree summatsup... oil clean when I changed it and again when changed after the run when I found it so hot, and nothing on the drain plug magnet.
Have you checked the temperature of your gearbox case after a hard run?
John

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Re: Gearbox Temperature

Post by kommando » Sun Sep 15, 2019 1:46 pm

After a long motorway run a Commando gearbox will get close to 100C, so that's a pre unit box where the heat of combustion cannot get unlike on a short Unit single engine. Not convinced there is an issue, the oil needs to get hot to stop it getting milky from water anyway.

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Re: Gearbox Temperature

Post by eebtr7 » Sun Sep 15, 2019 5:00 pm

May I politely suggest you get a temperature gun to determine the actual temperature of the gearbox. Compare it to other machines when possible. The next time I go out, I'll check mine and report back.

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Re: Gearbox Temperature

Post by Norman_John » Sun Sep 15, 2019 5:07 pm

“After a long motorway run a Commando gearbox will get close to 100C”
Interesting info! Maybe you are right, I await readings from those of us fortunate enough to have a sensor...
Cheers
John

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Re: Gearbox Temperature

Post by eebtr7 » Sat Sep 21, 2019 6:19 pm

Okay, my fellow Iron Men of BSA! Here are the temperatures as recorded a few minutes ago, 11:50 AM. I lit the fires and chugged up and down the local hilly streets to reach full operating temperatures. The ambient air temperature is 88 degrees with a dew point point of 71 degrees. Here are the readings from my temperature gun with the engine at idle.

Gearbox at the filler plug- 132 degrees F.
Clutch housing at the clutch rod access plug- 95 degrees F.
Oil filler neck- 95 degrees F.
Spark plug- 215 degrees F.
Exhaust pipe at head- 225 degrees F.
Muffler- 102 degrees F.

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Re: Gearbox Temperature

Post by Norman_John » Sat Sep 21, 2019 9:45 pm

Hi eebtr,
I am very grateful for you taking the time to do this. So it seems that the 'box on my B44 probably isn't doing anything too unusual. :lol: Guess I'll have to go and worry about something else instead...

I changed the oil again this morning, this time for a heavier weight oil and after taking it out for another spirited road test the gears seem quieter - less of the straight cut gear zizz you get when a unit single gets warmed up. Temperature seems the same.

I'm appreciating the Pazon by the way, dead easy to set the timing and much easier starting now. Just flood the carb ease it over compression and one kick usually starts it, and a nice even idle too.

Thanks again
John

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Re: Gearbox Temperature

Post by SteveS » Sun Sep 22, 2019 7:25 am

Hi eebtr7
.
Useful temperature :thumb info
.
I'm not quite as old as some of the European members of this forum and Celsius is more meaningful than Fahrenheit. Hope you don't mind me adding the info to your list:
.
  • Gearbox at the filler plug............................132F, 55C
  • Clutch housing at the clutch rod access plug......95F, 35C
  • Oil filler neck..........................................215F, 101C
  • Exhaust pipe at head.................................225F, 107C
  • Muffler..................................................102F, 39C
Steve Sewell

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Re: Gearbox Temperature

Post by beat » Thu Oct 03, 2019 3:32 pm

:thumb :thumb

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