bestrcpilot

This is what I do. Fix the crack using a exopy from the hobby shop, the kind that is used on RC airplanes and fiberglass cloth. Then coat the inside with Caswell tank sealer. Never leave gas in the tank always drain the tank after a ride and never use a one way value on the vent line. Still using a SM tank I fixed this way for 4 years now

As a big guy myself 6' 210 pd I would go for a 250. The 125 is going to have a hard time of it. And on a 125 after a year on it your going to want something bigger. You can always drop the compression and add a flywheel weight on a 250 to tame it down.

My Dad used to get these hubs from SM back in 70s when he would build up the SM high boys frames with Bultaco engines. The hub and rims are lighter then the stock Bultaco hubs and shoulder tims. Wish we had kept a couple of the high boy frames.

Here are some pictures of my set up The first pic is of the carb on my ty250 mono This pic is of the foam tape on the frame for the idle screw This next pic shows where the Idle Screw is touching the foam tape. And this last pic shows the spacer that I used on the back of the air box to move the airbox about 1/2 inch to the front so the rubber hose from the air box to the Carb would meet up with the carb

Sorry about the above post. please remove it. So after the Request for pictures about the flat slide on my bikes. I went out to the shop and looked at my setup again. It has been over a year since I rode them. So anyway I was wrong about having to grind a slot in the frame. I just used a couple of pieces of foam tape on the frame where the Idle screw would touch the frame. I will post pictures from work in the am and explain it all better then. too many beers to work it out tonight

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Hi Guys I used a TM 28 Mikuni on both of mine ty350 and ty250 monos. The jets that came with them are the ones still in them, never had to change them the bikes run great with the stock jets. They were straight swap, the stock intake rubber works, the rubber boot for the airbox works as well but it is close to being to short. And yes the choke lever is "wrong" side but still works. The only thing is getting to Idle screw it hits the frame. But a little time with the grinder put a notch in the frame and once the idle is set there is no need to get to it in the last year. If you really need the jet sizes I will go out in the shop and take the carbs off and look. let me know

The trouble I had with my carb was the chrome had come off the slide and the bore in the carb was out of round. The bike would run but would hunt at low revs. The carb off the TY350 is the same. The TY250 as you know was not inported into the US but there were a lot of TY350. I guess Yamaha did not think we would want the smaller motor even if it was a better motor. Good luck with it.

Getting parts in the US is going to be hard. The best place is going to be England or ebay. If the carb is giving trouble, best to replace it. I could not get my ty250 mono running right until I replaced the carb with a 28mm flat slide Mikuni. Best $100 I've spent on it . If you have a older Yamaha Dealer near you check with them for parts. You never know what they may have on the shelf. A lot of the parts are the same as a 83-85 YZ

Sorry for not keeping the thread updated sooner. Well the frame is out of the jig. Had to give up On the idea of using a DT frame. The DT head stock that I was going to use would not work, the bearing size was not right. So it took awhile to find a Donor TY 250 frame. The only thing that got used was the head stock and front down tubes the rest had to be cut away. Anyway the frame is done and work is now Continuing with the swing arm. I'm now looking for a shock/spring setup for it as the DT shock/spring setup is too stiff. Pictures of the build and a complete write up will have to wait untill the bike is up and running.

Back in the day my Dad would change his Bultaco around, ever time a new tank/seat, frame, wheels would come on the market. So I would not worry about the fact that your bike does not look like what came out of the factory. It's a piece of family history. Get it running and have fun.

Thanks for all the help. I passed the info to my friend.

By changing the point gag, you are changing the dwell. The dwell is the time that the points are closed. Why is dwell Important, when the points are closed the power is building up in the Condenser. Think of the Condenser like a Battery that has to recharge so the the dwell is the Length of time that a condenser has to recharge. The shorter the charge time the weaker the spark. When the points open the power is sent From the condenser to the high tension coil and then to the plug. The system that is used in these bikes is AC not DC. I hope this helped answered your question.

The number ia 19900001. Sorry about the extra 0s. The paperwork that came with the bike states Bultaco Competition Department. It is believed that this is the bike that Yrjo Vesterinen rode in the world rounds Would like to be able to prove this. thank guys

A rare 199 maybe? A friend just picked up a 199 with the Serial number 000001. This bike was found in the USA. With paper work that shows the bike came straight. from Bultaco it has macthing numbers on the frame and motor. Does anyone know about this bike?

Arizona in July it too hot. Price of gas. To far to drive from the east coast.

I to had a Mony 247 that sat for years and would not start. after cleaning everthing to with in an inch of my life. Still would not start. It ended up being rust on the cam on the flywheel that open and close the points. The point were opening two times per revulsion. Something to check.

Clean the points with a piece of white paper between the contact points. Any dirt will keep the points from closing and making spark. Check with a omh meter to see if the points are making contact. The hd coil must be mounted to clean bare metal. Unhook the kill swicth. Check the plug cap with a ohm meter that it is not open. Hope this helps Good luck

I use a web cam hooked up to a old computer to record on a 1week loop, it takes a picture evey 10sec. and can be viewed from the web or on the telly at home. A motion light that lights up the inside and outside the shop, stops a lot of people. Anyone thats trying to break in want to do it in the dark and not in bright lite. And it never hurts to have the 12ga shot gun at the ready.

Having been bite by the same bug, that your Dad has. Start slowly you don't want to show how bad it can get. Never let the "dirt" into the house, until the wife is not at home. Never call the place that you work/store the bikes the garage, the building out back, or man cave it is a shop! But honey when I'm in the shop,you know where I am. I could be down at the pub drinking and looking at all tbe women.

If the new plug cap is the hard black one. Check the side of the cap and see if it has a 5 ohem sign on it. If it does change it out, these caps with a resistor in them do not work the old mags. Almost drove me crazy on my Bultaco until I found the brand new NGK cap was not working.

The only way I could get my Ty350 run nice and and rev. Was to replace the carby with a flat slide 28mm and reshape the cylinder head. The stock slide and carb body seem to wear almost as bad as a Amal.

I have been running the Boyesen newest reed for about two weeks now. I did not find any change in the motor with the new reeds.. They can be a pain in the a*** getting them to seal on the reed gage and if not sealed the motor will run rich.

Hello west you do not say which TY you are talking about, a 175, 250, or mono. If a 175 using a MX head is a way to up the compression. On the 250 some people would use the Dt head in order to use a decompresser. And both of these were done back in the day. Hope you find this of help.

A coil spring is rated by the force it takes to compress the spring 1 inch. So to check the rate of a spring put the spring on a scale and compress it 1inch and read the scale.