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Discussion Starter · #1 ·
I have just got my oil pumps lines and oil pump delivered my bike is highly tuned **** abby fast road tune and jm corsa 34mm flatside silver top about 34bhp italkit reeds bc engineering head i have been using motul 720 and 800 and castrol A747 but now want my pump going on motul 720 with just a bit of A747 in the tank to bring it up to 32 to 1 so is pump 100 to 1 so anyone good at maths just lost a 140 italkit 700pds top end cause was too lean so need advice on ratio and premix thanks lads
 

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i guess you dont really need it, unless youre going to WOT for like an hour or so. We SEA sometimes do that to our 125cc 2t. if so we generally add 10ml oil for every 1l petrol. Due to some of us cant afford fully synthetic oil or castor based.
 

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Discussion Starter · #3 ·
What ratio is that then bet it smokes like me nana yeh I used to race a brand new kx250 and used cheap oil garage two stroke and just guessed never had one fault with the engine bike was new and I was only 17 still at school so didn't know what i was doing but races only last 15mins and you only have 3 a day plus 10mins practice
 

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125cc Sportsbikes Boffin
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Pump delivered ratio depends on throttle position, etc. The pump is effectively a reciprocating piston moved in relation to engine speed, with the stroke of the pump controlled by the throttle position.

In theory you could modify the cam the throttle turns and the shape of the bottom of the piston to adjust the stroke differently and so change how much oil it puts out.

From memory the stock ratio is given as between 0.8% and 2%

All the best

Katy
 

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Yes, the manual says between 0.8% to 2%. I spent some time testing two oil pumps I have before I decided to fit the newer one.

Interesting thing is that when you set the pump as per the book (for the markings to line up properly) it doses almost no oil at idle. So I adjusted the throttle cable a bit (about a millimeter between the marks) and now it does give it a tiny amount of oil at idle.

At high revs and over half throttle it doses quite a bit. I think it is even more than the manual says. I used to run 35:1 premix. And when I swapped to the pump the running temperature dropped by few degrees. However, I haven't rejetted it yet. So it might be due to it running a little richer as a result.

I haven't done any sustained motorway riding with the pump yet. Hopefully I'm not going to regret my decision to use the pump when I do.
 
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