Hoske silencer on '84 R80

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SandyHackney
Posts: 1
Joined: Fri Nov 06, 2020 12:10 pm

Hoske silencer on '84 R80

Post by SandyHackney »

Hello friends,

I am putting the 38mm Hoske silencer on my '84 R80. It runs fine now. After installation do I need to do any rejetting? Thank you!

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schrader7032
Posts: 7400
Joined: Fri Oct 27, 2006 3:00 am
Location: San Antonio, TX

Re: Hoske silencer on '84 R80

Post by schrader7032 »

Welcome to the forum! Not sure if you need to or not, but I would monitor how the bike performs with the new mufflers. Starting, acceleration, gas mileage, plug color, etc. If the performance substantially changes post new mufflers, then you'll need to figure out where the issue might be.

Snowbum has a page on intake/exhaust tuning...this might give you some ideas:

https://bmwmotorcycletech.info/InExTuning.htm

You may want to do what's called a "plug chop". This is done...safely...by running along in top gear at say 60-70 mph and close the throttle and kill the engine while safely coasting to a stop. When it's easy to do, pull each plug out and look at them...if they are very whitish then it's running lean; if they're blackish then running rich. This is all contingent on on what unleaded fuel now does to plugs. In the old days, with all the additives, plug color was a big deal. It might be changed somewhat with the latest fuels.
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

MikeL46
Posts: 120
Joined: Fri Jan 01, 2016 1:58 pm

Re: Hoske silencer on '84 R80

Post by MikeL46 »

Probably no need to rejet. The stock BMW mufflers are pretty good flowing.

To be safe do the plug chop as Kurt says. Run the bike at speed (65-70 is good) for at least 5 minutes before shutting down to check the plugs.

Mike
67 R50/2 w/R100 engine/trans and Ural Sidecar
69 R60/2 76 R90S 78 R100RS
70 Triumph w/Spirit Eagle Sidecar

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