MaRtIe Posted June 28, 2014 Share Posted June 28, 2014 hi guys my stepdad's bike has been quite rich since hes had it. it has had a FULL rebuild including all gearbox bearings etc but still has this lingering issue that we cant work out. it drinks a litre of 2 stroke pretty easy (under 400 miles). My bike of the same year and setup last's around 700+ miles. He's getting alot of black oil coming out the exhaust, runs very rich through the rev range. Stock jetting, float height has been set as per manual and it has a 3MB head with 3 wire powervalve, stock front pipe with a DEP rear. the pump operates correctly via the cables and also bob's up and down. the little marks on the pulley line up nice. i dont get it, because these pumps cant really be "adjusted"? typical really because he wants to sell it soon as he's doing his DAS but obviously cant sell it like this. Link to comment Share on other sites More sharing options...
hadley8899 Posted June 28, 2014 Share Posted June 28, 2014 Hello Martle, The only 2 things i could suggest are a duff pump (stuck open internally somehow) or there is a slight leak somewhere ? Be careful though becuase if its running very rich on 2 stroke oil it could lean out the mixture alot and cause a big hole in places you dont want one(piston) Cheers Link to comment Share on other sites More sharing options...
dt502001 Posted June 28, 2014 Share Posted June 28, 2014 Oh yes they can the stroke of the pump is to long re shim it to take the stroke out,bet someone had it appart and didn't put them back in.The alingment marks are to set the rotation the pump,, stroke length determins how much oil gets injected,per stroke. easy fix if you follow the book. Link to comment Share on other sites More sharing options...
MaRtIe Posted June 29, 2014 Author Share Posted June 29, 2014 gotcha, nice one guys. i knew it had to be something like that. i will premix it for now till i sort the shimming. wemoto have the shims in stock, i will get a digital gauge on the shim's that are on there now and report back. Thanks! Link to comment Share on other sites More sharing options...
Moderator DirtyDT Posted June 29, 2014 Moderator Share Posted June 29, 2014 You are comparing bikes miles per litre of 2 stroke. Are these the same bikes, ridden the same way on the same roads. I don't think 400 miles a litre is bad. Before you do anything, do the maths. a common ratio of 2 stroke to petrol is 1:33 so for each litre of 2 stroke, the bike should be using around 33 litres of fuel. If the bike is doing 60MPG, this is around 13 miles per litre (60/4.6). so extrapolating this; 13 (miles per litre) X 33 (33 litres of fuel @ a ratio of 1:33) gives you 429 miles per litre of 2 stroke. Looks about right to me. Black smoke sounds like gearbox oil is getting into the mix somehow. The smoke should be white. 1 Link to comment Share on other sites More sharing options...
slice Posted June 29, 2014 Share Posted June 29, 2014 Go Have a lie down DT you must be exhausted mate!! Link to comment Share on other sites More sharing options...
Moderator DirtyDT Posted June 29, 2014 Moderator Share Posted June 29, 2014 Link to comment Share on other sites More sharing options...
Moderator Cynic Posted June 30, 2014 Moderator Share Posted June 30, 2014 The smoke should be BLUE. Riding style will make a big difference. If he is chugging around at 3 to 4000 rpm with big throttle trying to use torque it will go through oil and fuel like an Arab. If he has a lifetime of car driving behing him 7k rpm will sound horrid. Even though thats where the bike wants to be. Link to comment Share on other sites More sharing options...
Moderator DirtyDT Posted June 30, 2014 Moderator Share Posted June 30, 2014 The smoke should be BLUE..... Sorry Jason. 2 stroke exhaust should be "Hint of Lilac" from the Dulux Solo range 1 Link to comment Share on other sites More sharing options...
Moderator Cynic Posted July 1, 2014 Moderator Share Posted July 1, 2014 Hey its a water pumper. You dont want pure brilliant white either. 1 Link to comment Share on other sites More sharing options...
Moderator DirtyDT Posted July 1, 2014 Moderator Share Posted July 1, 2014 True. That would be "hint of antifreeze" from the "I think its fecked" range. 2 Link to comment Share on other sites More sharing options...
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