2t autolube feed? Solved...I think

[stirlinggaz]

Hi all,
Technical question :
Most of my other 2 stroke bikes have been either pre-mix or the autolube pump goes to the carb.
On my Yamaha the pump connects to the manifold.
What's the difference?
Reason for question? I'm fitting a bigger carb (Some versions of this engine/bike come with dellorto 32mm carb as standard but mine has the mikuni 28mm)
I got the carb used, complete with manifold & yeis bottle but there is no nipple for the 2t feed.
I'm not sure if the dellorto vhsb32 has a 2t nipple on it like my other dellorto carbs.. & i dont have access to it just now.

worst case scenario: carb does not have the 2t input.
Is it just a case of drilling a hole on top of manifold & "glueing" in the 2t feed from pump?
I'd rather not blank off the 2t pump & go premix.

cheers,
GAZ
.
I've been told by Belgrada owners the vhsa32 has an oil input.
So looks like I'm good to go 😉

[Easy-X]

Whereas the idea with the petrol is to atomise it down to the smallest particle to make it easier to burn what you want with the oil is just to splat it onto the surface of the barrel and hope enough of it hangs around till the next dollop (with regards to autolube) so where the oil enters the system is not that important. (As long as it's past the throttle slide.)

The neat solution would be to look around for a replacement manifold that has the oil inlet. The Dellorto looks to be quite a compact carb and none of the ones Google Images throws up show a hint of an oil port.

If you have to bodge something up I'd suggest getting some itty-bitty brass pipe. I'm assuming it's a rubber intake manifold. If you can make a clean hole a tad smaller than the pipe it'll problem just stick there by friction alone. Worst ways, break out the JB Weld
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Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter

[jeffyjeff]

Hi Gaz.
Dude, I think you are taking a big risk if you decide to modify your intake manifold for the autolube pump. I suggest you find out how the Yamahas with the 32mm dellorto connect to the autolube pump and construct your system accordingly.

If you modify as you have described, you cannot be sure that the oil is metered correctly.

Be aware that you might not realize the power increase that you envision just by installing a larger carburetor. If your exhaust system is original, tuned for the flow from the 28mm mikuni, you may experience an imbalance that could negate some of the potential of the larger carburetor. Just my thoughts...

[Easy-X]

That's a good shout, there was a 28mm carb on my DT (stock is 24mm) and I wondered this but it also has a thinner than stock shim on the metering pump so (I hope) the previous owner accounted for such.
____________________
Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter

[Kickstart]

Hi

Tzr250 has the oil port on the carb rubber. Toying with converting my rd350 to the same, mainly in my case as one less thing to faff with when I take the carbs off.

Dell’Orto carbs often gave oil connection points.

All the best

Katy
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[stirlinggaz]

[redeem ouzzer]

Over analysing things. It really doesn’t matter if the oil inlet is on the carb body or the intake rubber as the intake charge will atomise it and pull it into the cylinder regardless.

I wouldn’t poopoo premix, now I’ve tried it I wouldn’t go back to automatic oiling. Engine much more responsive and spins up a lot faster without the pump and it’s train of drive gears, less to go wrong / service, less weight and less wear.
____________________
Be a REAL MAN!

[Easy-X]

Worth noting though that an oil pump varies the ratio based on throttle and engine speed. Less oil used at idle, more used under high load, therefore kinder to the environment....*

*Obviously we're all very, very concerned about such matters when you get 2 smoking. Straight face now, no tittering at the back!
____________________
Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter

[Kickstart]

With the rd I intend to buy some reed block spacers, and drill those to mount the oil feeds, rather than trying to drill the actual intake rubbers

All the best

Katy
____________________
Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[stirlinggaz]

[stirlinggaz]

[A100man]

[Easy-X]

For my Yamaha the specs say it varies from 160:1 to something like 16:1. Only burning as much oil as you need = less asthmatic kittens killed!
____________________
Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter

[Kickstart]

[stirlinggaz]

oops, double post

[stirlinggaz]

Hi all,
Sorted. I think.
Brung the carb in from shed & was able to have a good look at it.
& yup, just like other dellorto carbs it has a wee brass nipple for the 2t oil 😁

So i was worried for nothing, still curious why there's 2 different places to connect the pump though, as mikuni carb doesnt have the input but connects at the manifold instead.
When I bought the dellorto it came with a manifold (which does fit the bike) which is stamped with 3BN which I think correlates with a DT125 whereas my original manifold is stamped 4FU which matches with everything else on the bike.


cheers,
GAZ

[stirlinggaz]

[redeem ouzzer]

[stirlinggaz]