How to destroy a Rotax disk valve!!

[NSR]

Or what a complete idiot I am!! :quoi: :quoi: This weekend was to be my first ride for the year.

It is simple really, just leave a 10mm nut in the air box

Lucky it was free revving and not under load at the time it stopped.





Should I attempt to fix these gouges or would it be better to leave them?

[THIERRY]

RIP crankase!
So stupid, once i forgot the oil in tne gas....you'll never walk alone Noel! :clin:

[jmb]

OUCH !!!!!!

What a fuck !

[gitane-mais]

[Doudou77]

Bad trip !

As we say in French "il a mangé...."

[vinduro77]

Indeed you are not alone...
Just repaired a customer 250 RS.GS motor after having the same 10mm nut traveling this time through the disc valve straight to the bottom of the crank (at least saved all the top end)
So, result, magnesium welding needed and a lot of filling and liquid paste to ensure no leak in both half casings.

Unfortunately, as much as we love SWM, the matter of dismantling often the air box to work on the carburettor or change the rubber boot, have to too many owners been an expensive mistake when refitting these nuts.

Do not feel too bad, welcome to the club! :clin:
Cheers, Ph.



http://youtu.be/blqprEVxkzY

[NSR]

Thanks for the comments.

With the chances of obtaining a left case almost nil. Has anyone fixed damage like this?
I am thinking maybe fill the holes with weld and then have it milled where the disk runs.
I know this not the best solution but it may be the only one.

Cheers
Noel

[THIERRY]

Two solutions Noel:

+ http://www.srcf.fr/forum/t5499-reparati ... ROTAX.html
+ find another one in good condition

[swm 29]

bonjour
moi je serais bien curieux de savoir réellement la perte de puissance qu'engendre une grosse rainure sur le carter

pour moi le disque fonctionne comme un clapet qui ouvre et ferme les gaz d'admission comme la jupe d'un piston

alors rainure ou pas je vois même pas ou il y aurait un problème d'etancheité ou une perturbation des gaz

prenez un carter, coller un disque en position fermer remettre la pipe et souffler coté carbu

faite la même chose avec un carter bien rayé ou oxydé ,ben vous verrez aucune différence

c'est surement basique comme expérience mais ça m'interroge
pour la pratique je viens de remonter un 250 rotax avec le carter bien défoncé j'attend que le proprio le remettre en route pour le tester
jc

[gedeon34]

Sans être expert en rotax ou autre d'ailleurs, je dirai que l'étanchéïté risque de poser un probleme lors de la descente du piston avec un refoulement des gaz.
Un peu comme des clapets effrangés ou abimés.
Pas grave pour le fonctionnement mais rendement afecté.

[MotoSWM]

Hi Noel

I have a decent used 175 crankcase available.

I will email you with some photos to make sure it's the one you need

Regards

Martin

[NSR]

Thanks All for your input. Thanks Martin I will be interested later in the year. I will be in England in September.
With advice from someone with a lot of Rotax experience, I have had the case repaired. It is not an ideal fix but it works with the time and money I have at the moment.

One question, What gear should it be in when the gearbox gets installed?

[NSR]

I have made a stuff up when ordering the disk. I wrote down 224 105 instead of 100. So I have a 125MC disk. I see the 224 100 fits a 125GS & 175GS.
The question has any one run the MC disk in a 175? It my be better :hehe: but I doubt it :quoi:

[NSR]

The difference between the GS & MC disk