Derbi Senda sm 2007 49cc

[MaxwellAllan]

Good afternoon, I recently had a problem where my fuel jet screw was slightly blocked. I brought it home to clean it and the bike began working again. However, I'm having a bit of trouble with it now. Since I bought it, it's been spitting oil, I went from 25/1 all the way to 50/1 in terms of oil to fuel ratio. Now that I've cleaned the screw in the carb, and replaced it inside, the bike seems to go 1000x quicker, this isn't a problem per say, but the bike is now essentially pouring out oil onto my hanging arms. When I was on a 'A road', I was in top gear and all out. I'm not sure how fast I was going but it was quite fast for me. About 60, I don't have a speedo, odo, or fuel gauge but that's besides the point. It was creating a whole lot of smoke, and by the time I got home, my swinging arm was covered in oil. Would the best solution be to unscrew the fuel jet screw slightly and test it. I thought that the further in it was, the more limited the amount of fuel the bike received. It has a https://www.dellorto.co.uk/shop/dellorto-motorcycle-carburettors-parts/complete-carburettors-dellorto-motorcycle-carburettors-parts/phbg-15-to-21mm/r2696-dellorto-phbg-21ds-racing/ for it's Carburettor. Is there another screw that would stop all the oil and smoke it gives off. It is 2 stroke so the oil and fuel is mixed. I'm fairly certain that the engine is also not legally 50cc, but unsure. Would it be advisable to reduce the amount of oil? It's got at least 35k miles under it's belt according to it's papers. Any help is really really appreciated .

[Robby]

Chances are that it's been messed with plenty in the past, so diagnosis gets tricky.

First off, fuel. Sounds like you are manually mixing it, but it should be an autolube system. First step is to verify that the autolube is still fitted and working, then check how it is adjusted against the workshop manual. Could be that someone has turned it up, combined with you putting in pre-mix, ending up in way too much oil.

Also, its a 2 stroke, its going to be smoky. If it isn't, something's wrong.

[MaxwellAllan]

[Riejufixing]

A quick Google indicates it may be under the seat:

https://www.manualslib.com/manual/1098193/Derbi-Senda-Sm-Drd-Pro-50-C-C.html?page=30#manual

[steve the grease]

Take the silencer off and remove the baffle , clean it and stand the exhaust up to drain , I have seen them with pints of oil in the silencer. Now it's running better, it could be blowing it out all over the place.