250 ED oil pump adjustment

[Hosk1956]

Help wanted, I'm adjusting my 250ED oil pump, the owners manual calls for the marks on arm and pump body to line up at rest, if they don't line up to bend the tang on the arm till they do.
As you can see in the photos, my doesn't line up but the tang on the arm is quite solid and is resisting being bent and frankly I can't see that it should/can bend that far.
What have others done? I am assuming that the oil control cable could be adjusted to take this slack out at stop rather than bend the tang. The bike has been like this all its life but the previous owner can't help me with how he had adjusted it.

Wayne from Oz

Pump arm at rest.

Should be here at idle

[thrownchain]

Use the cable adjustment to get it right.

[matt glascock]

The two keys are that the marks align when the throttle is closed and that the oil pump valve begins to move immediately at the slightest turning of the throttle - meaning no slack at all in the oil pump cable. My understanding of the Mikuni oil pump is that with the marks aligned with the throttle set to idle, there is a trickle of oil being pumped into the induction tract. The importance of oil injection at idle is debatable but I find it comforting at least. This is likely why the engine has not seized for the previous owner with the oil pump off at idle. Hopefully someone with more experience will give us the dope on this matter. Also, I can't remember if the zero stop alignment tab is on the arm or on the pump housing. I will try to get to the shop tomorrow and take a look.

[Al Harpster]

This may be a bit too cautious, but you might want to verify the pump is working.
I did this on my Suzuki 100. It's got a Mikuni pump too.
I spun the engine with a power drill with the plug out.
My pump wasn't.
I spent a load of time fooling with it. Modest success.

As far as proper adjustment: I don't have anything to add but it'll be safer to set it towards maximum & decide what to do from there.

Me: I'm putting 50 to 1 premix in my tank till I figure out what's going on with the Mikuni pump in my Suzuki 100.

Just a thought......

[matt glascock]

Al, you bring up a great point. While oil injection is very sexy and convenient, there is a downside. The system doesn't tell you when it stops working. From my personal experience, a malfunction in a five dollar part destroyed an awesome piston/cylinder set on a jug that had TWO overbores left on it. The WOT seizure was so bad the cylinder couldn't be saved. The culprit was a stuck ball valve in the banjo bolt at the intake tract. I'm thinking of doing one of two things. Either leaving the oil injection system in place AND running 50:1 premix which may result in double-dipping on the oil. I'd rather change plugs and cook the pipe more often than wreck another top end. Alternatively, the smart move may be just retiring the oil injection system altogether and running my usual 32:1 premix. Happily, I can report that I have not put straight gas into a 2-stroke motor since the day in 1971 when I cooked the old man's Lawn Boy. Running premix guarantees oil presence. Also, if the bike is going to be raced, I would not rely on oil injection. Al, my Suzy TM125 has the oil injection system removed. If your 100 is a race bike, you might consider the same.

[Tether]

Be carful with removing the oil pump on a Suzuki. The Suzuki CCI system pumped oil directly to the left side main bearing. Modification required to get oil to that bearing or the bearing will fail.

[Bullfrog]

My recollection is as follows:
1) The little tang on the actuation arm isn't all that hard to twist/bend to get the two reference lines to line up.
2) I also recall there being a need for an oddly aggressive twist/bend to achieve alignment. (It just seemed like the engineering could have been a bit cleaner/closer.)
3) The #2 recollection registered deeply enough to be remembered 40+ years later partly because the sharp point of the tang registered against the aluminum post . . . it appeared to me that over time, the point would "dig in" to the aluminum, requiring a readjustment. However, once the "readjustment" was completed, the tang would probably have achieved enough "bearing area" in the contact patch to not dig in further.
4) I would not recommend using the cable to adjust for "throttle off" alignment of the reference marks since any adjustment "drift"/wear allows the actuating cam to rotate past the "zero"/reference point.

Summary - twist that little tang and set up the pump as described in the Owner's Manual. Yes.
Ed

[matt glascock]

Correct Tether. There is a little shield covering the left crank bearing on the TM that has to be removed to allow premix oil to properly lubricate the bearing.

[Hosk1956]

Thanks for all the info fella's, you have been most helpful, I have done as the manual suggested other than bend the tang, I will get back to that and give it another go. The dog starts and is smoky so I suppose that is a good indication!
I was concerned about the oil pump actually working as Matt, it's not as if one can see the oil flowing thru the line, I loosened the banjo bolt but no oil leaked out which made me panic, so I removed the banjo bolt altogether and did see oil is coming out, phew, but there wasn't a huge amount, 2 thoughts occurred to me:-
1) The engine vacuum would maybe be sucking any oil into the crank so no oil would seep out of a 'loosened' banjo bolt.
2) Being 32:1 the amount of oil that would pump out would be miniscule in the moments that I ran the motor, after all that is 1 litre of oil to 32 litres of fuel, running for about 30 seconds = tiny amount of oil.
Pump or premix has me vexed as well, I have been on 4 strokes for many years now so the idea of the pump convenience appeals to me, mine will be an occasional commute and trail ride bike, no racing so I'll try the pump for a while.
Pretty pleased that I have got her running after a 30+ year slumber, fun times ahead I hope!

Wayne from Oz

[Hosk1956]

An update but i don't know if i should be concerned. Went out to Hody this morning and checked her over, noted an air bubble in the oil line. Decided on another run start and she started on the 3rd kick and ran like a charm, and watched the air bubble move up the tube!
So i know the pump works, now to check all the fittings for any air leak. Put the shifter and chain back on and take it for a ride.

Excited Wayne from Oz.

[Al Harpster]

Thanks to Tether for the concern about the left side crank bearing.

I'm aware of that. Funny, but the oil line to that side seems to be getting oil on my Suzuki A100.

The intake side, not. Even removing the check valve on the intake side results in no flow.

For guys that don't want to give up on pumps, or want to learn more you might do what I did:

Order one from China, the only place I could find one that (almost) matched my bike. These are very interesting devices.

For $27 (free shipping) you can buy one and take it apart & see how they work. Delivery is about 4 weeks.

I was able to take the key parts from the one I ordered and put them in the one I had.

Here's the link. It's a great price if anyone is interested.

https://www.aliexpress.com/item/Free-Sh ... 90aa90d425

Wow, that's some link. Or search on Aliexpress, Suzuki AX100.