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High drum rpm and no increase in speed reading.

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(@2smoke)
Posts: 16
Member
Topic starter
 

Having some slight issues with my setup (dynojet inertia dyno with yourdyno setup. 24 tooth pickup wheel) where the engine (drum) rpm increases massively, but the speed doesn't increase past about 5kmh. See pics, the motorcycle was in 3rd gear so should be reading around 100kmh.

Any ideas where I'm going wrong? 

Thanks!

 
Posted : 18/12/2023 5:38 pm
(@2smoke)
Posts: 16
Member
Topic starter
 

More engine RPM but very little increase in speed, the drum RPM has risen considerably though.

 
Posted : 18/12/2023 5:39 pm
(@2smoke)
Posts: 16
Member
Topic starter
 

And my toothed wheel setup

 
Posted : 18/12/2023 5:40 pm
(@2smoke)
Posts: 16
Member
Topic starter
 

Ok so seems I forgot to set the gear ratio in yourdyno. Have done that now and the drum rpm is reading better, but still no speed increase.

 
Posted : 18/12/2023 6:07 pm
(@admin)
Posts: 1456
Member Admin
 

Hi. 

Set the circumference of the drum here: Plugins->Speed and Distance.

The circumference is Diameter(meter) * 3.14

 
Posted : 18/12/2023 6:10 pm
(@2smoke)
Posts: 16
Member
Topic starter
 

Smashing thankyou. Thats made a difference, but my live HP reading is still very low. I've not done a power run yet as am still running in, but its barely reading above 2hp, any idea why this could be? 

 

Thanks

Paul

 
Posted : 18/12/2023 6:34 pm
(@admin)
Posts: 1456
Member Admin
 

Hi @2smoke, did you figure out what the problem was?

 
Posted : 03/01/2024 11:15 am
(@2smoke)
Posts: 16
Member
Topic starter
 

Posted by: @admin

Hi @2smoke, did you figure out what the problem was?

 

Not yet, haven't had much of a chance but I'm going to have a play tomorrow. Suspect the MOI is out!

 

 
Posted : 03/01/2024 12:59 pm
(@2smoke)
Posts: 16
Member
Topic starter
 

So, still no joy with the drum rpm, but the HP is accurate now with some fettling of the MOI and using a bike with a known HP figure,

 

The engine torque reading is way too low too, as well as the drum RPM being too high (like 25k rpm). 

 

Could it be my pickup wheel causing this? It's 24 tooth, but about 5/6mm thick.

 

Any suggestions gratefully received!

 
Posted : 11/01/2024 9:58 pm
(@2smoke)
Posts: 16
Member
Topic starter
 

Ok, so setting the gear ratio seems to have solved this.

 

Torque seems a little too high now. But have more bikes to test next week.

 
Posted : 13/01/2024 3:27 pm
Jostein reacted
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