Hi there

I have been able to get my 1976 Yamaha AG175 started after 15odd years of sitting in a shed. Fuel tank thoroughly cleaned, carby pulled apart and cleaned, new spark plug and fluids all sorted I was happy to get the old girl going. With a bit of trial and error I set the air adjustment screw approx 1.5 turns from closed and then adjusted idle screw to get her idling away. It would rev ok with throttle when stationary but as soon as I tried under power I started to run into problems. Generally it seems as though it is running very rich as it burbles and bogs down as I try to increase throttle. After reading a few old threads I feel it could be the small o-ring on the main nozzle. I have yet to take the carby apart again but I checked with my local dealership and they told me I can no longer order the o-ring (part number is listed as 248-14147-00) so next bet is to remove it and inspect. To try and get a new one I guess I am off to do the rounds of engineering shops to try and find a closest match. I was wondering if anyone has done the same and come up with a match that would help to speed up the search?

Also, I am open to advice for tuning the carby. It is a Makuni branded unit and I think same was used on DT175 and CT175 of similar vintage. Are there other common faults/issues I should also look for? Of course I will recheck for any dirt or blockages when I take it apart again.

Thanks
Ian

Ok might have jumped the gun - I see I can get an o-ring online (helps if you use the right part number in search). Any other comments or advice on these carbies and what to look out for?

On the Ag in "76 i'n not sure they still ran that carb with the Oring on the needle jet--side mounted main jet easily ID'd from a left sie view. If it 'is' that type of carb then yes--Oring replace for sure. But if it's a bogging on full throttle problem & doesn't turn out to be that then go looking at the exhaust. That's bogging as in no usable horses up in the revs--not bogging as in lean & wants to stop.

Thanks RT

Yep I’m sure it has an oring in there. When I cleaned the carby I didn’t touch it and didn’t take a lot of notice of it to be honest. I Have tried to add a pic of carby from phone but will try later if it doesn’t work

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With respect to the comment re exhaust - do you mean leaking exhaust as gases leave the head and transition to the exhaust pipe? I suspect a leak there too.

Should I be looking to replace jets, needle and seat etc whilst I have it apart again?

Ok cool, that answers the question. Re the pipe though in respect of performance i meant carbon blocking the baffle in the tail section & if that's restricted then i'd be thinking about burning out the whole pipe. Run it up the road minus the baffle if ya away from a built up area. Our just out of town area is getting more populated unfortunately & can't do the idiot thing we used to up & down the road. Although did put the bonnet through the windscreen of me Free 2.8 VW Passat recently, plus on my Free LTF400 quad i rescued yesterday, got it going about 7pm, thought Yay she goes so went down the road with a severely slipping auto clutch & back in the drive--AGGGhhh No Brakes & bashed into my V8 Audi & dented the boot. Not happy with myself. Not safe to be let out wife says--think she's right lol.

Here's a link to a very good post on the orings for the 125/175... both early and later.

Has info as to standard trade numbers and sizes that should work.

yamaha-enduros.com/index.php/forums/74-7...roblem?start=0#67102

I just wanted to follow this thread up in case someone later on has the same issue. The manual I have states small o-ring in the carby is 248-14147-00 but it is in fact a misprint which I found after receiving the wrong o-ring and having Yamaha confirm it as being an incorrect diagram. The part number for the small o-ring (#5 in the diagram) is 214-14147-00. The one starting with 248 is part #35 in the diagram.

After getting the right parts I have the old girl running fine and can move onto the next needed repairs.

Thanks for following up! That makes the search function work. Hard to use a thread for resolving issues when the result isn’t posted. But you knew that. My original parts list for Dt125a didn’t show the fork seal and retaining clip. I guess any search needs a second opinion to confirm.