1981 YT125 Chain Questions & 1982 Honda 250R Inquiry

[generallee2005]

Hey guys, back for more knowledge. The chain on these '81 YT125's, how important is the tensioner on such a short chain? I opened the case of mine for inspection & it was missing. I checked eBay for one, they have a NOS one for $30 shipped, but it doesn't include the sprocket. How can I get the sprocket for the tensioner? I'm going to call my parts place tomorrow, but untill then I'll have the thoughts passing thru my mind. Also, on these beasts, is it possible to run without the chain & brake covers? From looking I think it is possible for the brake to operate without the cover, but the chain looked like the tensioner mounted into the cover, but I'd prefer to go a nude chain! But, if I can fully commit to one, I'd just leave both covers in place.

Also, an unrelated question, I aquired a 1982 Honda 250R, the jug is bad, what is the going rate for the Hondaline 300R kits? I've searched the posts & found a few members that had a few at the time of posting, but no price listed & none are offered on eBay now. Since my jug is bad, what would my best option be for getting this one to run? I'm just feeling around, trying to decide the area I want to build this one (Restoration vs. Resto-Mod), as I'll finish the yellow one first.

If anyone needs pictures of the chain parts, I'll have some downtime tomorrow & can take pictures then.

I'll post a picture of the 250R because I'm that pumped about it, although I have yet to see it, I had a buddy of mine from where I grew up pick it up & store it until I can get back to the old stomping grounds.


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[EK-Racing]

I have a mildly ported jug from an 81' 250R it currently measures 71.93 mm. It will need a +2 over piston. Let me know if your interested.

[old-yellow]

i don't run a chain cover or chain tensioner and it works just fine.

[generallee2005]

Thanks EK-Racing, I think I've about decided to go with the 480, I've actually already bought the Mugen pipe & motor mounts made by BigBore. It's time to get crazy!

Thanks old-yellow as well, since my YT is missing all the tensioner, I think I'm going to do this as well. Do you have any of the brake cover on yours? I think if I've got the axle off, (to clean especially) I think I'll remove the plastic break cover. I just don't want to get it off & find out it's needed somehow.

[old-yellow]

I do have a plastic brake cover on mine but you don't need it to make the break function or anything else. What no pics of the YT125?

[generallee2005]

Here's the latest, I've got the pastics fairly well polished out. No pictures of this yet. Waiting on an air filter still, so I haven't bothered putting gas/oil in carb & remounting. I want to make sure it runs good before I get too much money invested in the look good. But I work at Sherwin Williams, so I thought I should go ahead & paint it & get rid of the previous owners camo job. So far, all I've got together is the first picture. The second picture is where I started. Hopefully, in another week or two at the latest, I'll have time to button it all together. Although, my light bulb on the oil sensor is blown, do you know where I can get a replacement? My local parts shop would have to order the whole new assembly, but I'm thinking I'll go to carquest & get a light set up that works & splice it in.

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[EK-Racing]

Cool. that 480 will run hard. I'm a fan of big bore trikes!!!

[old-yellow]

that front bracket on the front fork is a accessory as far as painting it i would strap the paint and restore the plastic. Here's a few links to doing that. http://www.3wheelerworld.com/showthread.php/24247-Sanding-restoring-plastic.-How-to-guide http://www.3wheeler.org/tech/fenderrefinishing.html
bike bandit sells the bulb - number 11
http://www.bikebandit.com/houseofmotorcycles/1982-yamaha-tri-moto-125-yt125j-headlight-yt125g/o/m147095sch232494

[generallee2005]

Man, I wish I had found the plastic restoration before I did Chainsaw's wet-sand/car buff method. Even still, the plastics still look 100% better than when I started, I just have a few spots to start over with the 220 to 320 to 400 to 600 to 800 to 1000 to, well you get the idea. That's why its been a 2 week project. I guess these things are a labor of love to make pretty!

[generallee2005]

I took finally got some time to take off my chain cover & got to thinking, if the chain breaks, I'll need a case saver. I'm thinking of hacking my chain cover & fabing up a case saver for the Tri Moto. Has anyone else done this? I have a pretty good idea of the area I'm going to go, but pictures of others are always nice starting points. Even though I had already removed the axle, getting the old covers off it really gave the old stud duck a more sportier look!

Here's looking to you my old yellow mentor! Thanks for all your help!

[old-yellow]

I never done it myself but trailprotrailprotrailprotrailpro give it a shot and on another note check this thread out. http://www.3wheelerworld.com/showthread.php/86220-Pro-Tec-175-Beginning?highlight=pro+tec+175

[fabiodriven]

:shiftyeyes:Trailpros:shiftyeyes:

[generallee2005]

I read the entire post, very interresting stuff. What's up with the Project TriMoto? Did someone make a hi performance yt? That's an idea I can stand behind. Also, I guess the TrailPros are just a popular tire that have a following? I noticed that my tires are Trailpros after fabiodriven's post, but I think I might be in the market for a new front, since mine won't hold air for long. I did order rear bearings, front sprocket, chain, oil light & head light bulb today, so with a weekend of work & a freshly pressure washed frame/motor/front tire at work, it looks like the time to reassemble everything else is at hand.

[generallee2005]

Got the old Stud Duck running today, for a while. Even though I dont have a back axle, or chain, or air filter for that matter. Before I got it running, I put in about a quart of 40:1 premix in the tank, & primed the carb with 40:1. I couldn't prime the oil injector because 2 of the bolts were rounded out, hence the generous premix. Of course it smoked like a train once it ran, but it did good. Before the carb seemed to almost "hang up" after letting off of the throttle, this made for no engine braking while riding, it is why I rebuilt the carb. I only replaced the O-ring on the big adjustment screw, since it was the only on messed up, all the others appeared fine. The second time I cranked the engine, it ran fine, still had the hanging throttle, so I adjusted the small adjustment screw a little to closer to 1.5 turns out from bottom, did fine, sounded sharper but the revs still hung once I let off the throttle. Once I turned it off, gas started flowing out of the overflow on the bowl, I turned off the petcock & tapped carefully on the bowl to get the float to turn loose, it stopped leaking once I turned the petcock back on. I did the same thing, trying to adjust a little on the big screw but when I did the motor just seemed to take off & rev pretty high, so I covered the butterfly with my hand to see if putting a little resistance would calm the motor down, like a simulated air filter & box would, it seemed to help, but my hand got covered with gas, so maybe I still have carb issues? Then this black oil started dripping from my exhaust pipe. I know I was running very oily, as by then my injection had appeared to prime itself, since I had replaced the hose running from the injector area to the carb, so should I drain the premix & switch to only pure gas now? Here's a picture of the oil coming from the pipe, & a picture of a hose that I assume is a crank vent, am I right? Any suggestions on the hanging revs? Obviously having a air filter would be more ideal to have on while trying to tune the carb, surely it won't cause the motor to just rev high like that.

Thanks again for helping a 2 stroke newbie!

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[old-yellow]

don't worry about the carburetor spraying gas on your hand and as for it revving up that should stop as soon as you get the air box on if not i would check for an air leak. i would run premix and block off the oil injection but if you trust the oil pump then drain the tank and put only straight gas. that is just a crank vent put a longer hose on it and put the end up high so it can't get water in it and by the way your missing the silencer for the exhaust.

[generallee2005]

Awesome, how can you tell the silencer is missing? Before I tore it down, I thought it was loud even for a 2 stroke. I need to post in the classified for a aftermarket pipe, but I want to get it running & going good before I spend too too much. Do you know if an 82+ airbox will fit the 81? I have a Uni airfilter for an 82+ my local parts place sold me to try & see if it would fit the 81, while the 81 air filters are on backorder. Once the 81 airfilter did come in, the foam had disintegrated in shipping & now the filter is back on backorder. I'm thinking of going to an 82+ airbox to keep the water off the filter, or going to a K&N without the airbox. I'm only concerned about water getting sucked in thru the airfilter, as really the only time the old stud duck will likely come out is after a good rain.

Also, fill me in on the Project TriMoto please, it sounds like some interestin stuff there.

[old-yellow]

http://www.bikebandit.com/houseofmotorcycles/1981-yamaha-tri-moto-125-yt125h/o/m147129#sch222396 part #19 and I'm not quit sure about the air cleaner so i looked on bikebandit and this is what i came up with. 1981 http://www.bikebandit.com/houseofmotorcycles/1981-yamaha-tri-moto-125-yt125h-intake-yt125g-h/o/m147129sch218275 1982 http://www.bikebandit.com/houseofmotorcycles/1982-yamaha-tri-moto-125-yt125j/o/m147095#sch215517 so i don't think so and as far as running a KN filter you would have to rejet the carburetor. back in December 1981 dirtwheels magazine decided to build a bad ass yt175 it had rear suspension an ported and polished IT175 cylinder with bigger reeds and a 36mm carb it was a six speed with a manual clutch it had custom exhaust a boost bottle, aftermarket front end, they advanced the timing. You name it they did to this YT175

[generallee2005]

Project TriMoto sounds like good stuff. I think I'll wait on my airfilter since I really don't want to start doing a rejet. Sounds complicated!

[generallee2005]

I'm having trouble finding a replacement front sprocket for the YT now. The replacement sprocket I bought from BikeBandit is the JTF426-13, as the pictures show the inside of this sprocket it not the same as what I have now. Talking to the rep at BikeBandit, the original sprocket, which I assume is what was on the bike when I picked it up has been surpassed by the new sprocket BikeBandit sent me. He pointed out the possiblility that the shaft from the tranny had been replaced, but considering the shape of the machine, I doubt this. Does anyone have a good front sprocket laying around that is not being used? Or know a sprocket that will cross over & work on the YT from a dirt bike or quad? I called JT Sprocket & the lady said that if I could find the JT part number that the new replacement sprocket surpassed she could look up inventory to see if there were anymore remaining in the warehouse, but she couldn't look up the previous number nor could the rep at BikeBandit.

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I'm also looking for a rear brake back up plate, part # 10 from http://www.bikebandit.com/houseofmotorcycles/1981-yamaha-tri-moto-125-yt125h/o/m147129#sch222668, a choke cable, and maybe a rear brake set up that goes on the handlebar, everything from the cable to the lever. If anyone has them, please let me know! Thanks!

[old-yellow]

https://www.denniskirk.com/parts-unlimited/sprocket.p8283.prd/828312.sku