Hello, I am new to the site and will post a separate new member introduction shortly! But in the meantime, I'm in the UK and have just bought a 73 DT250A to restore. It's in a bit of a state but largely complete and I have managed to get it running on pre-mix. The autolube pump looks OK (and appears to pump oil) but the pulley was a little 'graunchy' and was not returning properly. So I took it off and cleaned it, re-assembled and checked the gap. Haynes manual says 0.008 - 0.012 inch, but mine measures nearer 0.030 inch. I presume that a bigger gap pumps more oil? but is it likely that it was running with this bigger gap or have I managed to somehow re-assemble it incorrectly? Any advice/pointers would be really helpful. Thanks. Pete

Anyway, I'm worried that I may not have re-assembled it correctly and would like it serviced and checked over if possible.

Where on the pulley are you measuring?
I checked one of mine recently, when looking at the pulley end on at the 9 o'clock position the gap was smaller than the 3 o'clock position.
When you removed the pulley did you keep the shims in the same position, mine was correct and it had spare shims under the nut as washers.
If you haven't done so already have a look at the service manual in the tech library, it'll tell you how check the output, Rotate the pulley and count the plunger cycles eg. 200 and measure how much oil has been delivered.

from Salisbury and I look forward to seeing some photos of your bike.

It is quite important to know which model you have when ordering parts. If you do have a DT250A, then it will be a 1974 model (although the year of manufacture stamped on the frame might well be 1973). If you have a 1973 model, it will be a DT3. The best thing to do is check your frame and engine number against those shown in the VIN tables in the Tech Library on this site (see top toolbar).

Also in the Tech Library are loads of Yamaha manuals and I would strongly recommend using these instead of Haynes.

There was a complete makeover on a lot of models between 1973 and 1974 and not many parts are interchangeable.

Forgot to say from Berkshire

Thanks for the response. I had originally measured between the raised portion of the pulley and top washer when the pulley was fully closed. Interestingly, the gap gets smaller (close to spec) when I open the pulley slightly, so I guess its alright. Think the only sensible solution is to check the amount of oil it pushes through.

If that doesn't work out, is there anybody on the forum that services these pumps - I'm in South East UK. Thanks.

Forum Moderator DEET carries out this work. The good news is that his work is top notch, the bad news is that he's in the US! However, I am in the UK based aircooledrd club and a chap there services oil pumps and his work is well regarded. If you really do think that the pump needs a service, then I can put you in touch if you want.

Thanks - I'll try and test the pump over the next few days to see how much oil its pumping. If that fails, then I would be grateful for the contact details.

As an aside, the pump mounts on a bush - is it possible to pull the bush out from the outside, or do I need to remove the clutch cover? Cheers