after a bit of advice , noticed my fan was playing up a bit the other week and noticed that when i rev the bike the fan slows right down till stopped (3/4 revs )and when i let the bike go back to just tick over the fan goes full speed ?? the fan comes on and off as it should but wondered if the change in speed was correct ??

That sounds like a rectifier problem to me, I'm not familiar with Beta electrics, is the rectifier and regulator a one piece module on these machines? A Beta officianado needs to take over this thread....

it does sound like a rectifier ,its a box you get to it under the tank filler upper panel

If it is your rectifier then its on top of the gear box on my 250 4t evo, I assume the 300 is in the same place.

Thanks Gents , ive already replaced the fan regulator ( placed ontop of gearbox ) have to remove rear shock to get to one of the fixing bolts takes a lot longer than 1st thought lol but it doesnt seem to have made a difference so thats why wondering if other peoples bikes do the same ??

Just a suggestion here , phone Lampkins or Aklams up and see if there's a fix or if infact you have a problem . Second , ask them for the values /output at variouse throttle stages so you can start with a multimeter , last but not least check all your earth points , remeber this "VD is caused by dirty contacts "( Voltage drop ). Zeroed in on this as later this year i want a 4t . Keep us posted on your progress ,

Regards Ted

P.S why did you replace the unit in the first place ? If no one else can help , last ditch if you begin to struggle ,give Ferret a call on 07765832420 talk to him .

Edited February 15, 201313 yr by shyted

i spoke to alan @ feetup trialsport , the mechanic @ acklams and also John @ lampkins and all 3 said straight away its the fan regulator so thats why changed it will do as you say double check the connections and check for a decent earth , thanks

In the wireing lume there is a diode 2 wires in, one may be corroded.. i had same problem

Matt did you get this problem sorted out because I have exactly the same problem with my 4T

I have tonight dug the capacitor out of the wiring (for those who don't know where it is, its under the frame just to the left of the carb top, wrapped in adhesive tape) and it was blown, cost 60p for a new one which I had bought just in case and now bike appears to run perfectly will see if thats so at weekend

sorry Keith not been on here for a while so missed your post ? , with the weather and having to sort kids etc etc ive not even had chance to have a look at mine yet but good to hear yours is sorted i will take your advice and hopefully get mine checked in the next week fingers crossed solve the problem