125-200cc Electric oil pump question

Hi everyone
I running 2007 sms 125cc with aftermarket exhaust and dellorto 28 with 170 main jet, and i was wondering - how much oil giving my electric oil pump? Maybe i have to disconnect it, and making premix?

it varies the oil level depending on where the throttle is, ie, barely any throttle, can be very little oil, then at full revs throttle open, more oil. I had my pump break, wrecked my piston and locked back wheel at 50 mph, not fun. I used the new pump I put on for three years now, no issues, but I'm going to take it off and run premix, it's just safer, you know at all times your engine has lube. As your bike is the same as mine apart from the tyres, I'd say you should run 40 to one, if you're on the road with it. If you're racing off road you should run nearer 30 to one and jet it to suit. Ktm who makes the new husky 125s advise a 60 to one ratio! that seems stupid to me so I'll go with 40 to one is best overall. Take off pump and take oil tank out,block off the carb hole where oil pump goes to so no dirt gets in, drain all fuel out the bowl. Refill tank with premix, run it for an hour, take out spark plug and see what colour you get and how engine runs, if it's too black and sooted you're running too rich a mixture, if it's white on the spark electrode you're too lean. You want it a nice brown/ grey colour

oh also I'm running a 130 main jet in dellorto 28 carb and that is slightly too rich so I don't know how yours can run with a 170!

thank you for reply!
It's my first bike after cpi sx 50, i've just got it, and know nothing about dellorto 28 tuning. I've got it with 170 main jet. I wiil rebuild it whole, because curves hands man ride it befor me.

temperature difference, humidity difference, different pipe

the more air flow you get in the motor the more fuel is needed

if the air is colder it means more oxygen is packed in the volume you pump through the carb (air is denser packed)
if the air is less humid less water is in the mix and the ratio for oxygen is higher

more oxygen as a percentage of the total you need more fuel
more volume passing through the carb you need more fuel

its all about the ratio and total quantity that passes through the carb

Robert-Jan

I didn't know the main jet sizes varied that much, I thought the max size would be maybe 150 ish and lowest around 100. So if mine is too rich running a 130 main in soggy england, if I were to ride it to spain I would need a small main jet to compensate for the change in the air/ humidity? I'm trying to learn these principles, all I've done jetting wise is remove them for a clean, never actually jetted it to suit

in the mikuni vm/tm series...the mains can go from 100 up to like 700..very large span..
not relevant i know! but interesting perhaps..

I got a 128 for my pbh dellorto, the hole is different in size, enough to see with naked eye, I thought the diametre size would be far less noticeable. See how the 128 looks? if it's that much smaller with just two sizes less I can't imagine how small a 100 main must look

I believe you have old model carb, I mean PHBG? 130 main jet for PHBG is good. Sendman has newer VHST carburetor because his bike is newer one with electric oil pump. VHST likes bigger main jet.

yes mine is an 05 pbh dellorto or phbh? something like that, 28mm

Your -05 should have PHBG, which uses smaller main jet than the newer VHST carb with TPS