Hi all
My newly acquired DT175B came without an oil pump however I bought a job lot off eBay , they have different numbers stamped on the outer cable holder .could anyone tell if if any are suitable for the 175
I have 2 with 4L1 stamped 
1 with 364 stamped 
And 1 with 49301 stamped
Thanks
Dave Burn 

4L1 is for RD250LC (Europe).

364 is for MX250, probably 1973.

493 is for TY250, probably 1975 and 1976.

On the face of it, not suitable for your DT175.

Thanks for the info
I have another with 1M1 stamped on it ..
Can you tell me what that is off please ?
Cheers 

1M1 is the model code for the 1977 on DT250MX model (ie the mono shock version).

Just to clarify, use of the oil pumps might not be limited to the model codes stamped on the pulley, as the internal geared parts can be different. However, I'd be surprised if a pump with a 250cc bike code was used on the 175.

If you haven't done so already, have a look for images of any known correct pumps on the internet and see what is stamped on those.    

Not been able to find that info
So if anyone is in the know ??
Cheers guys 
 

My Yamaha tech bulletins for 73 and 74 show pulley number "364" was used on 1973 AT3 125's, CT3 175's DT3 250's and RD250,RD350 and for 1974 DT125A, DT175A,DT250A, TY250A, MX125A, MX175A, MX250A. plus RD250, RD350.

Pump assy. p/n are: 214-03 for the 1973 AT3, CT3 and DT3. All 3 bikes the same number. 364-00 for the 73-74 MX250.
1974 is 248-00 for DT125A
402-00 for DT175A
438-00 for DT250A

Minimum & maximum pump strokes CC's were the same for the AT1,AT1B, AT1C, CT1,CT1B,CT1C,DT1B,DT1C,DT1E for the 1969 thru 1971 models. So could be the same for later year bikes, same models.

Pump color codes: yellow on all the AT1 125's and CT 175's, Black on the DT1's.
 

Yes, Yamaha often used the same "piston size" in the pump on different models so the volume per 200 strokes will be the same.  Don't let that fool you into thinking the pumps are interchangeable!

The key is they used a lot of different "gear ratios" on the worm drive gears.  If you try to use a pump with a different ratio internal gear that doesn't match the gear on the pump driveshaft, you can easily destroy the drive parts. 

I do not believe a DT3 250 pump will work on a AT125/CT175.  They are not the same as far as I know.  Be careful and make sure the pump driveshafts are the same.

I will have to double check but i am pretty sure I bought a used oil pump from a CT1 or CT2, rebuilt it and installed it on the 1970 DT1C. The 70 DT1 didn't have a oil pump on it when i bought it. I think at that time i checked all the numbers and all was good. Worked great. I will see if i still have my records to verify it and report back.

(update)
Ok, the E-bay listing for the used pump i purchased read: 1971 Yamaha CT1 175, DT250, RT360 oil pump 214-13101-04-00.
So technically it could have been off any one of those bikes. I bought it because of the part number match. I don't remember any color codes on the pump. It was a oily dirty mess before I rebuilt it. Either i got lucky and it was off a DT1 or if it was off the CT1 or RT1 it ended up working fine. It's been on the bike for 4 years now and working great.

 Looking at the data there is a difference in primary reduction ratio's between the smaller AT1/CT1 and the larger DT1/RT1 which makes perfect sense.  
However the final worm gear reduction is the same at 55/1on all 3 models according to Yamaha's data sheet.
The difference is in the primary reduction ratio's which is:

28/19 x 55/1   AT1, CT1
20/21 x 55/1   DT1, RT1

So the way i take it the pump speed is faster supplying more oil on the DT1/RT1 then on the AT1/CT1 with the same amount of crankshaft revolutions.
Be careful what you buy or use if it's not 100% known what bike it came off of. especially if the color code is gone off the pump and there are no other markings.  

     
 


 

As time went on, Yamaha made an effort to reduce the number of oil pump part numbers which is what they say in the 1973 Service Bulletin those part numbers came from. 

But that doesn't mean 125 and 175 pumps are always the same as 250 pumps on the earlier or later models.  

Plus I don't know of any external markings on the pump that positively ID what it fits.  Yes, the pulleys have numbers sometimes, but that same pulley could be on dozens of models and different pumps.  For example, the RD250 and RD350 also both have "364" pulleys.  But they are for twin cylinder bikes and definitely not the same pump body as the singles.  

I have never seen much documentation on earlier bike pump worm gear ratios.  The later specs have that info.

Like I said, you need to be careful that the worm drive and driven gears are compatible.  I'm speaking from experience.  

Guys
Thanks very much for the info 
The 364 marked pump has a yellow dot on it and slides on beautifully 
All the others don't , as the worm drives are different pitches 
So with care I'm going to try the 364 pump
Once again thank you, 
Regards 
Dave Burn