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Older dyno jet (motorcycle dyno) 100/150

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 Rob
(@rob)
Posts: 29
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Topic starter
 

The dynojet roller has a number stamped into the drum on the flywheel side, this number is the MOI for that drum, use this number in your dyno MOI and all should be fine. Still early days, but I will know more when the engine rpm sensor gets here.

 
Posted : 17/02/2020 2:48 am
 Rob
(@rob)
Posts: 29
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Topic starter
 

Update: the dtec RPM adapter came in today, this was very easy to install with instructions on yourdyno web page. It is working very well.

Still need to figure out why the engine rpm is reading proper but on the graph I believe it is showing drum rpm? I wanted HP/TQ VS engine rpm, NOT drum rpm?

As I don't know how to set the drum rpm, and really don't want to have to set the drum rpm with every different bike? Or is this mandatory?

I really wish this page had more action. I am so new at this, but with help I know I can become very well versed with this stuff.

 
Posted : 17/02/2020 10:49 pm
 Rob
(@rob)
Posts: 29
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Topic starter
 

Update, the trigger wheel I had made was to thin, and maybe not enough teeth, I really only made the wheel this way because I had saw another post from someone using same dyno as I am here in the forum, so I copied their trigger wheel, however it would not read accurate.

I have made a new trigger wheel and this time I made the wheel to exact specs as listed on this web page, made by CNC, this worked much better and now this small issue is fixed.

However I am still having issues with something else, but can't seem to figure it out.  I believe the new issue has to do with rpm and gear ratio, setting engine rpm with d-tec unit, locking gear ratio, but HP and TQ values are not what they should be, well hp is close but TQ is not what it should be, for example if bike has 15 TQ on dynojet dyno, my dyno says it has 28 TQ, also hp/TQ values cross at way to high of an rpm for example if they are supposed to cross at 5000rpm, they are crossing at 8000rpm as an example. Jostein has been very helpful, I was having some serious frustrations at first, but as I get familiar with everything I see it is not as difficult as I was making it. This current issue is proving to be very difficult to solve tho! My test bike is a 2014 yz250f. It is just so odd, cause everything seems to be as it should! Engine rpm I believe matches the rpm of the engine itself (bike has no tacho) but usually rpm is off by double, and this I am 99% sure that engine rpm is correct. For some reason I am doing something wrong or something is going wrong with the engine rpm/drum rpm/gear ratio part I believe .

this coming weekend I have new test bike coming and a friend, maybe 2 brains, 4 hands, and 4 eyes can make things work. The new test bike will be a Yamaha r3, and good thing about this bike is it has a tacho, it also has dynojet programmer engine management system, so everything the bike is doing can be logged on lap top with this unit and certain it is correct, and can compare to what the dyno is saying, also we know proper gear ratio for the bike, so if something is not working correctly here with the dyno, we can manualy insert proper ratio!

i will update, in hopes one day this will help someone. i sure wish I had a blue print to follow rite rite now with this exact set up! The one other guy I see on this forum who has done exactly as I am doing has not updated his post in a long, long time, and he also has not gave much detail. When I do finally have this figured out I will put up everything in one post so it is easy for the next guy.

 
Posted : 02/03/2020 10:56 pm
 Rob
(@rob)
Posts: 29
Member
Topic starter
 

Picture of new trigger wheel made to exact specs as specified on this web page.

 
Posted : 02/03/2020 10:59 pm
(@admin)
Posts: 1457
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As mentioned, your gear ratio is wrong. 

HP and Torque always crosses at 5252 RPM when using imperial units and at 7121 RPM when using metric units. This is independent of the software or settings, it is just the formula. Remember that the left (HP) and the right (Torque) Y-axis can have different scale. 

 
Posted : 03/03/2020 12:33 am
 Rob
(@rob)
Posts: 29
Member
Topic starter
 

If I wanted. To manually enter the gear ratio?

I looked online and the bike I am testing (2014 yz250f) says it has a final reduction ratio of 3.846 (stock sprockets) (stock tire size) this number of 3.846, is this the number I enter into yourdyno in actual gear ratio box?

 
Posted : 03/03/2020 12:50 am
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