2 Strokes Down Under

Hey lads. Can u simply remove oil Pump and cap off oil feeds into the cylinders? (replace banjo bolts with standard bolts) Will this produce any problems? Ie carbs not tuned for premix?

I'm sure it's been done before.

What's the issue with the oil injection?

Is the bike being used for racing or road riding?

Have a search on here about premix, oil pumpsand so on, there's been a few discussions and some good points made.
There's also a chap known as Arrow who has a good rep for rebuilding oil oumps.

I have 350 barrels on the ds7 so my oil Pump won't keep up or. Isn't calibrated for that?

Best ask member Arrow for a definitive answer..
.. but AFAIK Yamahas have tended to use a fairly basic oil-injection set-up..

Even the later stuff, like RZ's pump it to the carb/inlet tract only,
unlike more sophisticated Kawasakis/Suzukis which pumped it to the crank too..

Likewise, modern oils likely are sufficiently improved - to give enough protection,
on the dosage provided for normal road-use running.. & going premix is a pain for that..

Hopefully arrow will be along to fill us in, but your right, by the time the RDs arrived, they used different pump ratios for the 250/350. Not sure about the R5/DS7. A check of the online parts listing at Partzilla would show you.

Probably wouldn't prove too difficult to track down an R5 pump? Easier, cleaner and more accurate than premix.

I'm certainly no expert, but the pumps allow for different ratios at different revs, premix is whatever you mix it and thats that.
If you're putting a bigger displacement on your motor then one of the more experienced on here may have someuseful tips.

Hi, its possible to use the worm and pump from the 350. The parts come up on eBay. 250 to 350 oiling is around a 30% increase.
Arrow.

So will the R5 and RD350 pumps be interchangeable Arrow?

I am more (totally) confident with the later a/c and lc/ypvs/tzr pumps. I would need to see all the parts in front of me to say for sure.
Arrow.

Just to add, Yamaha changed the gear inside the 350 a/c pump during the production run, so two different pumps.

Can the OP try running a static pump output test & see how much it is delivering?

If it compares ok with what a later model 350 gives, it should be sweet..
It might be that those early `70s pumps were set up for a high ratio, due to the available oil quality then,
& because a smoky exhaust wasn't such a big deal emissions-wise then, either.

Pump output is measured in what comes out per 200 strokes which makes all the twin outlet ones all the same! How quickly it does 200 strokes is due to many different gear and worm combinations, and white plastic drive gears/primaries.

Interesting point

Ta Arrow, but Is there a standard volumetric pump output measurement figure quoted for each model?
- & to reference/test check his against?