1973 Yamaha AT3 125 two stroke enduro

tuxedodale · Oct 27, 2011

I'm new to the forum, found it last week surfing the net. Two weeks ago I drove 90 minutes to the OK border to pick up what was described as a very nice original 73 AT3 Yamaha. Upon arrival it appeared the owner was over selling the condition. I didn't want to go home empty handed so I left with said bike in hand minus $300.

I got the bike running yesterday for a brief period. It didn't run all that bad but I suspected the crank seals were leaking so I now have the engine cases split and seem to be deeper into this than I wanted to go.

Anybody have any suggestions for parts services etc., in the DFW area? Looks like I will probably have the cylinder bored or at least miccd out. I think I need new crank bearings and seals along with fiber clutch plates and maybe piston and definitly rings plus gaskets and seals. The rest of the bike is mostly there, the front fender is banged up and the paint should be refreshed.

I might just get it running reliably and sell it though, any thoughts?

greeneggs&ham · Oct 27, 2011

Re: 1973 Yamaha AT3 125 two stroke endure

Many years ago (mid 1990's) I had several KDX's that the dealer did not have time to search for parts. I found these people willing and knowledgeable, so I purchaced alot of parts from them. Good luck. Post some pictures. Sam

http://www.midwestactioncycle.com/

Not sure he will work on anything this old, but he does great work.

http://www.cookseycrank.com/

BPFowler · Oct 27, 2011

Re: 1973 Yamaha AT3 125 two stroke endure

Bearings and seals are the easy part. They can be sourced from your local bearing supply.

Pistons are still available. The rod is the same as the rd200 I think. So no problem there either.

+1 on Andrew fixing up your crank. I would let him press on a new set of mains while he was at it.

If Andrew wont do it check out http://www.rb-designs.com/

Have fun and enjoy.

pkiser · Oct 27, 2011

Re: 1973 Yamaha AT3 125 two stroke endure

I have a 1968-1974 Claymer Yamaha service, repair handbook for enduro and motocross singles. If you would like to have it, pm me your address and i'll mail it to you.

pk

tuxedodale · Nov 1, 2011

Re: 1973 Yamaha AT3 125 two stroke endure

Ok, you asked for some pictures. This isn't my first time but I do it infrequently enough to forget. I'll see if this works.

I'm still on the fence on wether or not I should start pouring money and time into this project. I have a feeling in the end I would have been able to pick up a fully restored one for less money than I'll have in it.

Any advice, part it out or rebuild?

Robert K · Nov 1, 2011

Re: 1973 Yamaha AT3 125 two stroke endure

Boy, I spent many miles in the woods on a yellow tank AT1. Finally sold it to get a CT1 which became my first motocross bike. Sure have many good memories of these bikes and I think it's one of the things pushing me to get a TW200.

ed29 · Nov 1, 2011

Re: 1973 Yamaha AT3 125 two stroke endure

With only 3400 or so miles on the clock I would reconsider the cylinder and piston work. Unless it shows signs of damage or has pitted from sitting it should have a lot of miles left in the original bits. I had a couple of DTs a very long time ago with several times that mileage on original piston and rings.

Try to avoid the "while I am in there I might as well do this too" trap. Avoiding that will still give you a good running, fun bike without spending way too much on it.

greeneggs&ham · Nov 1, 2011

Re: 1973 Yamaha AT3 125 two stroke endure

If your intent is to get it running and sell it, I don't think you want to sink a ton of money in it. But I agree with Ed, I would not replace anything that was not suspect, even if your intent was to enjoy it for awhile. If the cylinder & piston is not scored, I would think rings only. As for the crank & bearings, since you have no history, I would visually check the crank & replace the crank seals. If you see anything suspicious, send the crank to a knowledgable person and have it checked. The fender can be saved, it would be good if you have a friend with a dolly and some putty.

Keep an eye on flee-bay for a fender and small items. The turn signals can be found, and I think I saw somewhere that a company in Cali. is restoring gages. I will need to access old memory for that one thou.. :lol2:

Again, if you are not going to keep it to enjoy, then I suggest do the minimum.

tuxedodale · Nov 1, 2011

Re: 1973 Yamaha AT3 125 two stroke endure

Update, I brought the cylinder, piston, crank and cases to DFW Honda today, I live fairly close. The service guy, who seemed very knowledgable, measured the piston and said it needed bored and maybe 2nd oversize in order to clean up the cylinder. He also thought that the crank needed rebuilding because of some up down play in the rod.

I went to the local tax assessor office and did a vehicle inquiry with the VIN number, $2.00 (I was trying to find the original title, no luck). I found the name and city of the last person that registered the bike in 2002. A quick search on the phone produced a phone number so I dialed it, Wichita Falls. I dialed the number and the previous owner answered. He told me he sold it to a guy that ended up moving to OK.

He told me that he changed the engine from a 1972 AT2 that he bought because the original transmission locked up. He still has the engine along with frame and some other parts.

I believe the engine may have much more wear on it than the mileage indicates. I am leaning heavily into cutting my losses. I was originally hoping to do some minor tuning and have a bike I could ride around the neighborhood for little cash.

I also checked into getting the title and it appears that is going to be in the $150 to $200 range for a bonded title.

I am losing motivation, maybe part it out on Ebay?

Marc B · Nov 4, 2011

I wonder how bad or good the top end is on the original engine along with bearings etc. unless it's been sitting outside. just thinking out loud.

Monkey Wrench Cycles · Nov 4, 2011

Re: 1973 Yamaha AT3 125 two stroke endure

tuxedodale said:
Update, I brought the cylinder, piston, crank and cases to DFW Honda today, I live fairly close. The service guy, who seemed very knowledgable, measured the piston and said it needed bored and maybe 2nd oversize in order to clean up the cylinder. He also thought that the crank needed rebuilding because of some up down play in the rod.

I went to the local tax assessor office and did a vehicle inquiry with the VIN number, $2.00 (I was trying to find the original title, no luck). I found the name and city of the last person that registered the bike in 2002. A quick search on the phone produced a phone number so I dialed it, Wichita Falls. I dialed the number and the previous owner answered. He told me he sold it to a guy that ended up moving to OK.

He told me that he changed the engine from a 1972 AT2 that he bought because the original transmission locked up. He still has the engine along with frame and some other parts.

I believe the engine may have much more wear on it than the mileage indicates. I am leaning heavily into cutting my losses. I was originally hoping to do some minor tuning and have a bike I could ride around the neighborhood for little cash.

I also checked into getting the title and it appears that is going to be in the $150 to $200 range for a bonded title.

I am losing motivation, maybe part it out on Ebay?

I say fix it. Shop around on eBay for parts, and if the last owner sold it to the guy in OK but the other guy never changed the title then have him file for copy of title. Costs $5...

tuxedodale · Nov 6, 2011

I'm not familiar with the copy of title, sounds like a tempting option if it is only $5. I got the impression he is not doing well health wise, he said it would take a week or so for him to get out to the garage and look at what he has. I'm thinking I'm going to rebuild it, just not sure how extensively.

I talked to the guy that runs North Dallas Cycle Specialists in Denton. He measured the top end and said that I could get by with rings or a new Std. piston and rings but recommended a crank rebuild. He came up with 3 thousands clearance between piston and cylinder. He said the crank had some life left but didn't know how much, he recommended the crank while I have it apart because if it lets go I lose the engine.

I can get the rings and piston for around $40 but the crank rebuild looks like $200. I'm thinking about trying to get the original engine, if not for the correct numbers on the case if nothing else. It sounded like he may be willing to just give it to me but not sure, I don't want to pay much for what he has left I don't think.

david_ · Nov 8, 2011

Tires look ok. Probably needs a new chain. How are the brakes and fork seals? That can be more $$$.

I've never had any luck getting previous owners to help out with title issues - I've done two bonded titles in the past. Now that I'm familiar with the process it's not too bad, but the first time around sucked. Trying to get this street legal? It will have to pass inspection before you can get the title, FYI. Expect to pay ~$100 for the bond plus your regular taxes/registration.

I've been where you're at.. honestly, unless you love it, I'd get it back together running with new rings and sell at a discount; no title, needs motor work. Consider it a learning experience - always be ready to walk away from a purchase.

Monkey Wrench Cycles · Nov 8, 2011

tuxedodale said:
I'm not familiar with the copy of title, sounds like a tempting option if it is only $5. I got the impression he is not doing well health wise, he said it would take a week or so for him to get out to the garage and look at what he has. I'm thinking I'm going to rebuild it, just not sure how extensively.

I talked to the guy that runs North Dallas Cycle Specialists in Denton. He measured the top end and said that I could get by with rings or a new Std. piston and rings but recommended a crank rebuild. He came up with 3 thousands clearance between piston and cylinder. He said the crank had some life left but didn't know how much, he recommended the crank while I have it apart because if it lets go I lose the engine.

I can get the rings and piston for around $40 but the crank rebuild looks like $200. I'm thinking about trying to get the original engine, if not for the correct numbers on the case if nothing else. It sounded like he may be willing to just give it to me but not sure, I don't want to pay much for what he has left I don't think.

The copy of title is basically a lost title with you being the owner. So if the title is in that guys name still he can go down to a main DMV office (we have one in arlington that deals solely with titles and liens) and pay $5 and have it printed on the spot OR he can send off to austin for it but the wait is a few weeks i believe.

I would get the original engine to have a spare and be able to use the original cases. I also would go ahead and pony up to have the crank rebuilt. Cranks dont last long when the bearings have play...

tx-fisherdude · Nov 8, 2011

tuxedodale said:
I'm not familiar with the copy of title, sounds like a tempting option if it is only $5. I got the impression he is not doing well health wise, he said it would take a week or so for him to get out to the garage and look at what he has. I'm thinking I'm going to rebuild it, just not sure how extensively.

I talked to the guy that runs North Dallas Cycle Specialists in Denton. He measured the top end and said that I could get by with rings or a new Std. piston and rings but recommended a crank rebuild. He came up with 3 thousands clearance between piston and cylinder. He said the crank had some life left but didn't know how much, he recommended the crank while I have it apart because if it lets go I lose the engine.

I can get the rings and piston for around $40 but the crank rebuild looks like $200. I'm thinking about trying to get the original engine, if not for the correct numbers on the case if nothing else. It sounded like he may be willing to just give it to me but not sure, I don't want to pay much for what he has left I don't think.

I have a 73 125 parts bike last I checked it wasnt froze. If you plan on fixing it up I can hook you up cheap. A 175 jug and piston will fit that motor but the starter wont work as well but it dont work very good anyway. BTW I dont live very close I'm close to Galveston but will ship

tuxedodale · Nov 9, 2011

Thanks all for the input, I'm going to check into getting the other owner to help me with the title copy. I still have another lead on the next owner in line but no answer on the phone yet. The 175cc thing is interesting.

Thank you very much PKISER for the manual, if you ever get close to DFW I owe you a beer at the very least. Now I have an official reference to help me put it back together.

I know I shouldn't be doing to much to it but it's my nature, I'm just not in love with the bike. I was originally looking for a Honda four stroke XL250 74 or something along those lines. I love two stokes but I was just wanting to put around town on something a little more mellow.

I always wanted to learn how to paint and I'm thinking this might be something good to practice on. I want to get the kids involved as well.

tuxedodale · Nov 9, 2011

Ok, I just saw this on Craigslist, this was a little more of what I was looking for but a bit old.

http://dallas.craigslist.org/ftw/mcy/2693908288.html

Should I cut my losses part out the AT3 and go down this road? Not sure the wife would support this.

I talked to the other owner and he said he would sign the paper work for the title copy if I sent it to him and then drop it in the mail for me. I sent him everything he needs except for his signature and copy of his license. If he does this I should have a title for less than $5.

Monkey Wrench Cycles · Nov 10, 2011

tuxedodale said:
Ok, I just saw this on Craigslist, this was a little more of what I was looking for but a bit old.

http://dallas.craigslist.org/ftw/mcy/2693908288.html

Should I cut my losses part out the AT3 and go down this road? Not sure the wife would support this.

I talked to the other owner and he said he would sign the paper work for the title copy if I sent it to him and then drop it in the mail for me. I sent him everything he needs except for his signature and copy of his license. If he does this I should have a title for less than $5.

I saw this yesterday as well. I also saw another AT3 for sale in running shape for about the same price.

Anyways those are nice bikes and you couldnt go wrong if you decide to go with that one instead.

tuxedodale · Nov 10, 2011

Former owner called today and backed out of helping me with the title. Anybody have any advice on how to get the bond for a bonded title, my insurance doesn't seem to know what I am talking about? I'm looking for a bonding company that can give the $6k bond cheap to someone with excellent credit.

That Honda sold in less than an hour, talked to the guy today, he didn't answer when I called yesterday, that was a good deal.

Monkey Wrench Cycles · Nov 10, 2011

tuxedodale said:
Former owner called today and backed out of helping me with the title. Anybody have any advice on how to get the bond for a bonded title, my insurance doesn't seem to know what I am talking about? I'm looking for a bonding company that can give the $6k bond cheap to someone with excellent credit.

That Honda sold in less than an hour, talked to the guy today, he didn't answer when I called yesterday, that was a good deal.

Yeah, that was a REAL good deal.

That sucks he backed out. I'm guessing he also backed out of hooking you up with the original engine? For bonds call a farmers agent. That's where I've found bonds the cheapest.

tx-fisherdude · Nov 10, 2011

tuxedodale said:
Former owner called today and backed out of helping me with the title. Anybody have any advice on how to get the bond for a bonded title, my insurance doesn't seem to know what I am talking about? I'm looking for a bonding company that can give the $6k bond cheap to someone with excellent credit.

That Honda sold in less than an hour, talked to the guy today, he didn't answer when I called yesterday, that was a good deal.

go on TXDOT website it will tell you what you ned to do to get a bonded title. that parts free. they will give some phone #'s of ins. companys that do the bond that will cost you 100 bucks

david_ · Nov 14, 2011

I used A-MAX the first time, wasn't impressed. The second time I used the bond guy in the same building as the title office (Carrollton). That went smoothly.

Just be sure to double and triple check the VIN and address on all forms so when you finally do get to the tax office, they don't catch a mistake that costs you more time.