I have made the decision to delete the oil pump and run premix gas. It seems silly to leave it in and just have it spinning dry. I have not removed it and don't even know what it looks like not in the bike. I could use a little help. Thanks ....Matt

What model and year is your bike? On my DT3 I'm running a blockoff plate. But had to remove the clutch side cover to remove the drive gear for the pump. And honestly if your pump works and you ride the bike on the street. I'd leave it on. I've been thinking about putting mine back on

There are about four different things that need to be done to remove the pump. But the first thing we need to know is what bike it is and why?

asco

81 dt 125H ..... I have toyed with the idea of keeping it .... thought I had it working.... then nothing ...it just scares me to think that I could cause damage to the engine ... I would always wonder if its working and it would kill me to mess things up when it is so easy to run premix gas ... I have removed oil tank and all tubing ... using little nipple covers wehre tubing use to go .... Matt

Okay. I will try and explain to you the process. First the side cover in front needs to come off. Two bolts hold on the oil pump. Then that entire sidecase ( drain the oil ) needs to come off so now you need to buy a gasket for the clutch side and remove the plastic gear inside. Then, you need to buy a block off plate with another gasket. Then, because there's oil in the gas tank it changes the mixture in the float bowl. Which means you need to change the jetting. Which means now you potentially need to buy carburetor parts. Now, you've changed three things. So what - have you gained by doing so? Do you have more peace of mind? No. If you kept the oil injection in place, had a safety buffer of adding 32 to 1 premix in the fuel tank the only thing you would need to change is the main jet on the bottom of the carburetor. You would need to go one size larger.

I hope that I explained this well enough to somebody who needs help making these decisions?

Ask-crow

My thoughts--good or bad--just what i do!!. Pump will be safe left on & capped off with oil in it. Just reduce the pump stroke to minus zero by removing the washers behind the plate
www.partzilla.com/catalog/yamaha/motorcy...1981/dt125h/oil-pump Remove washer 'or washers' 8 in the link pic & put them on the front side of the plate behind the spring washer, so you'll know where they are if you ever want to revert back to using the pump. Pretty reliable pumps unless someones been 'in there' & fiddled!!. Leave the line up to the cylinder as no stroke means no oil going anywhere except lubing the pump internals. Remove the cable of course!!, although there would be a way of leaving it connected if you needed the extra tension the pump cable return spring gives to help pull the throttle back but i won't go into that as complicated it enough for one night. Oh, & if you remove the pump cable totaly you'll find you'll need a heavier throttle return spring. Maybe not but it'll be super light without & you'll need a nice free throttle cable to be safe.

Edit--actually talking oil pumps--today i was going through my sheds starting what had live petrol in--god that stale petrol is bad news down here, the smell you can't get rid of--anyway, came to my MR50 which is a monoshock 50 Yamy, tank cap off & gave it a shake, no fuel. Just went to pour some in & then thought oh hell that's right i'd 'de-commissioned' the 'oil pump' & had the fuel mix in the oil tank running to the carb as the petrol tank was rusted out underneath she started so i wobbled off down the drive on flatish tyres & back then put it away again. Is sold & paid for from 6 months ago to Ron Hebberd who i know quite well but lives in the south island & will collect it oneday for his collection as doesn't have one & are a bit of a rare breed down here in NZ. You've never seen an MR50 this bad that still runs well but should be in the scrap metal bin---mind you that's most of my bikes.

virtualexhibit.marlboroughmuseum.org.nz/...xhibit1/e10014a.html

i was wondering why I was so close to stock jetting at my altitude... I think the premix gas is the issue ... thanks for the plans on removal ... they are quite helpful ..wondering if a gasket kit may be the way to go ... bike is in great shape with just over 3000 miles but age takes its toll also ..I want everything to be able to go back should I decide ... thank you ...Matt

got brake pads front and rear ... get some gaskets and take care of that oil pump .... maybe get some fork seals and make a weekend of it

I have a 1976 DT175E with an oil pump to do the premix. I'd like to disable the pump and keep it on if I want it back but for now just mix the pre mix myself and pour straight into the gas tank.  Has anyone run into this? I'm also wondering what ratio to run if I can get to the stage where I can mix the premix.
 

I'd take it off or leave it on.  Every pump I've ever seen disconnected and left in place ends up getting ruined.  You can always run premix and the pump at the same time if you're worried about pump failure or something...  You could disconnect the cable from the pump to minimize output. 

P.S.A 1976 would be a "C" model...  no 1977 175D model...  1978 was the monoshock 175E model...  big jump in model changes there so it will be helpful if you check VIN numbers against the charts in Tech Library to identify what you have.  Titles and registrations are notoriously inaccurate at times with regard to year model on these old bikes. 

Thanks Mark. It is monoshock so must be 78. I'll check the VIN. Good info about the pump.