Help please! 582 not getting revs

[Loco]

Other things to check:

Ignition Timing (even 0.5 degree will give you big rpm changes)

Carb/s actually opening fully.
Same Air cleaners (some air cleaners allow more air than others)
Same carb jetting (not so easy to check)

Spark plug same type/gap correct
plug leads good order
Resistors on plug caps still fine ( dunno if applicable)

Then of course. ... Same fuel, same oil, same fuel/oil ratio .. etc etc etc

Awesome stuff many thanks we'll go through all these and try eliminate the problem

[Karman]

Found this now as well: Rotax Debug info: http://www.rotaxservice.com/documents/t ... oot2ST.pdf (that is for 2stroke)

[German]

Justin

I read the post . You cannot assume that if you try a propeller off one Trike onto another that the pitch will be the same. This is not true, as the angle of the hub may differ on both planes, thus altering the pitch angle on the Prop, when you swap them over. The ONLY thing that will effect the RPM on the engine, is the Propeller. I wait with interest to see the results of the findings. Let us know.

Regards

[Loco]

Quick question guys, Ian did a compression test on both trikes

Other trike (standard size pistons) that gets 6200rpm reads 7.5

My trike (new 1'st oversize pistons) reads 7.2

Can't one assume this is normal since its a bigger volume?

And can that be why I'm getting less rpm?!

[Loco]

Another anomaly...

Trike A - standard size pistons
Trike B - my trike new oversize pistons

1. A gets 6200rpm with its own prop and exhaust
2. B gets 5800rpm with its own prop and exhaust
3. Ian put A's prop on B, B now gets 5700rpm (100 less so it seems A's pitch is a bit more than B's prop)
4. Ian put A's prop and exhaust on B, B now gets 5850rpm (150 more since last time so it seems A's exhaust is better)
5. Ian put back B's prop so now it only has A's exhaust, B now still gets 5850rpm (so why did we get 100 less at point 3?!)

Eish these Rotax engines are black magic

Perhaps something's wrong with my rpm guage, does anybody have a hand-held rpm guage or something I can borrow just to be sure please?

[mulderpm]

Ant, I am no expert but for what it is worth my thoughts are. The two engines are basically not developing the same power. If the only thing you changed was the rebore, oversize pistons and rings, then I would imagine that running her in for longer will make her looser and she should develop more power over time. In the mean time, to up the loaded revs, make the pitch finer on your prop. Else check all the things mentioned by Karman. You could also consider swapping the carbs between A and B.

[mulderpm]

Ant, my engine max rpm varies by 100 rpm from day to day . I attribute this to atmospheric changes. She revs max 6480. 400 rpm difference is not right. Try swapping carbs...it is relatively easy. As you mentioned, try using a hand held tachometer on both A and B. Some timing lights have one built in. If you have EGT's fitted you could compare that as well. Full throttle, max rpm, I get between 610 - 620 deg C, that is with altitude compensated main jets (158). If you get below 600 you are running too rich or your slides are not opening fully.

[Loco]

Thanks you know where I can borrow/buy a tiny tach?

[mulderpm]

You could try Hans or Alex or a motorcycle tune up place, like Mean Machine or Motorcycle Meca, else Midas or Autozone sells them.

[KlapperKnop]

Thanks you know where I can borrow/buy a tiny tach?

Ant, I have one which I used on RC props.

[Loco]

Thanks you know where I can borrow/buy a tiny tach?

Ant, I have one which I used on RC props.

Cool so I should be able to get them at RC hobby shops as well?

[mulderpm]

Hi Faiz, Does it measure prop revs? Then you will have to multiply the reading by the gearbox ratio to get engine rpm...else just compare the prop revs between A and B. I also want to borrow your metertjie, please man. Check if my tachometer reads correctly, for once and for all. Pedantic hey.

[KlapperKnop]

Thanks you know where I can borrow/buy a tiny tach?

Ant, I have one which I used on RC props.

Cool so I should be able to get them at RC hobby shops as well?

Or you can just borrow mine?

[KlapperKnop]

Hi Faiz, Does it measure prop revs? Then you will have to multiply the reading by the gearbox ratio to get engine rpm...else just compare the prop revs between A and B. I also want to borrow your metertjie, please man. Check if my tachometer reads correctly, for once and for all. Pedantic hey.

This measures prop revvs. Tolerance is +/- 10rpm as the LCD display reads RPM actual/10. Will bring it along tomorrow for those that needs to check at ML. This little tachometer has the option for 2 blade, 3 blade and 4 blade ....

[Loco]

Or you can just borrow mine?

Awesome thanks man!