Olijnyk

Iv recently bought a Yamaha DT R 125 1997 and now that im insured iv been out on it a few times, It starts fine and can ride it about good but when stopped at lights or a junction i have to keep revving it which gets pretty anoing in slow moving traffic or when i have to stop but rev at the same time . The problem is that when the revs drop down to 3000rpm that will be the point that you have to rev the bike or it will cut out and revving it when it gets down to 3000rpm it will make a "blub blub" kinda noise as if there is to much air getting in the engine and same with lowwer revs so it cannot idle at when stopped otherwise it will cut out . I need more help on this my mums boyfriends mate said it would be the crank case seals or somthing but i just need some help on what maybe to do , had this problem with my RS 50 when a part of the air box was not in and to much air was getting in and as soon as i put the part back in it started up fine so i am thinking that it is a similar problem with this ? could this be right and if so how to i change this . Just need to know : What the problem could be ? how to solve this ? If there is a screw to adjust how much air intake there is and were it is ? sorry if there is not enough info here not to good at explaining things and not the best on mechanical stuff haha but if needs be i can be more detailed and write another description .anyhelp would be great thankyou

Recently got a new DT 125 and now thinking of over the months changing adding and moving bits around to make the bike look nicer . Started this post to show my bike now , along the way and eventually the end result . Also thinking about one day getting a helmet cam and starting a youtube channel . So you can all see how its going and then see what i get up to on it