Hello guys, I have a little problem with my DT50R BJ. 93. 70ccm Polini, Sport-Krümmer, serial exhaust In the 5th course the part does not really get to speed. I have to turn up in the 4th course up to over 65km/h, which also goes without any problems. When I turn into the 5th course it tortures itself a little bit. 70km/h I still manage, but then also no long ground wave can come. I notice the “rise” then, although it is very flat on the Lower Rhine. The tempo falls then rapidly and I have to enter the 4th course. All other gears can easily be turned up…… My thoughts were the following: throttled CDI: but then why can the other gears be turned out? Carburettor set incorrectly: but why can the other gears be turned out then? Air filter is cleaned. The machine has already run faster (so 80 on ́m Tacho) As a candle I use a NGK BR8HS. Original is a BR7HS at 50ccm. However, the original Yamaha roller (sorry) of my r girlfriend also a BR8HS ??????? Does anyone have a reasonable idea what I could try out here? Oh so, one should also mention that I am 1.90m long (CW value from a fridge) and so bring about 130kg on the scales (my little DT moans there). I wonder that here everyone is looking for a 6th course. With me a 6th course would be as useful as a wooden leg for ́n divers !!!!!! Greetings Schmal66