intillect Posted June 13, 2022 Report Share Posted June 13, 2022 I am working on a Beta REV 80 for my buddy and am having some issues I would love insight on. The first thing that I am struggling with is the clutch master cylinder, no amount of bleeding creates any pressure in the slave cylinder so the clutch never disengages. I am assuming I need a new clutch master cylinder but can't find a factory one so my question is will a generic one work? Has anyone else had to go with a generic one? I guess the slave cylinder could be the issue but the master doesn't do anything when pumped so that's why I am starting there. The second thing I am having issues with is the carb, I have rebuilt the carb twice and both times the bike will start first kick but then idle as if its running out of gas and the idle hangs real bad when you rev it. I have heard the stock carbs on these bikes are trash but I am just fixing this bike for him to sell so I don't want to dump a bunch of money into a new carb if I don't have to. Any insight to either of these issues would be awesome. Quote Link to comment Share on other sites More sharing options...
Mwl Posted June 13, 2022 Report Share Posted June 13, 2022 I have beta rev3 125, I changed fuel cock, found swarf from when it was manufactured, also changed inline filter, can see the difference,filter now fills very quick, idling may be down to either, Quote Link to comment Share on other sites More sharing options...
intillect Posted June 13, 2022 Author Report Share Posted June 13, 2022 I didn't think to check the fuel petcock, good idea! I will just run a piece of hose straight from the tank to the carb and see if that helps at all before buying new stuff Quote Link to comment Share on other sites More sharing options...
kaarelj Posted June 26, 2022 Report Share Posted June 26, 2022 On 6/13/2022 at 6:20 PM, intillect said: The first thing that I am struggling with is the clutch master cylinder, no amount of bleeding creates any pressure in the slave cylinder so the clutch never disengages. I am assuming I need a new clutch master cylinder but can't find a factory one so my question is will a generic one work? Has anyone else had to go with a generic one? I guess the slave cylinder could be the issue but the master doesn't do anything when pumped so that's why I am starting there. Slave cylinder gasket could be also worn out. But it would puke the oil into gearbox. So the oil level should decrease with lever pulls. Easy to check, just unscrew 3 bolts and hold (pinch together) the slave cylinder with thumb. You either feel no pressure when pulling clutch lever (worn out master cylinder). Or you might feel slight pressure but definitely see some oil puking out. You'll figure out how to disassemble clutch master cylinder. Most likely the master cylinder piston gaskets are worn out. Then the oil will pass from one section to another and straight back to reservoir. Thus not generating any pressure. On Betas case the master cylinder is not repairable. So buy new one or swap with Braktec. Braktec BT46000CT-CWT-1 worked fine for me as piston diameter is the same (9,5mm). Same is used on all GasGas (from 80 to 300). Just point out that mineral oil is used, not dot4. Quote Link to comment Share on other sites More sharing options...
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