bestrcpilot

the biggest gain with the TY intake track is gained by maker the connection to the air-box the straight as possible. As most of the trouble with the intake is a pinched intake rubber hose between the carby and the air-box. If you ride it like a modern bike.IE.. lots of revs and using the clutch, then opening the top of the air box up will help it to rev better. Now if you are running a short header pipe and after market exhaust and porting then a bigger air-box and a straighter intake track dos help. IE. using a Yamaha RD 350 intake (from the reed plate to the carby.) And make sure the reed are sealing as after 35 years they are know the lift and not seal. The use a new carby as the stock one are also know the wear and and not run right. Hope this helps

The silver frame is a model 49 mark2 A replacement frame from Bultaco sometimes did not have a number on them, but check by the right foot peg .

I find that most cables for the front brake are to long which give a spongy feel to the brake as the cable flexes to much. Try making the cable as short as it can be. It does Help

If you really don't want to do the swing arm mod. Then try useing a dt 175 swing arm. You will have to redo the tabs onit but it's longer then a ty arm Just use a an early dt. By lenthing the swing arm will help keep the front end down on the hill.

Sound like the trail is wrong. Go with a set of ty250 triple trees and ty250 forks. Fixed mine. I to tried a set set of triple trees that were parallel to the headstock the bike felt like I was falling off the front end and sloppy side to side just terrible put the ty250 set up on it much better. Also use the upper triple tree that moved the handlebars in front of the pivot point..

I have no trouble with IRC tube type staying on the rim with my M49 Bultaco even when I run them down to 4 psi.

Pull the side cover and see if ignition is full of water also check the amount of oil in it and see if there's water in the oil. Change plug. Reclean carby again. Check flywheel key.

Check the points and timing.

If alloud a Mikuni 24mm flat slide works for me.

I was using condenser that I had in stock from 1974. That is why I had two go tits ups. I now use new ones and no more failures.

By all means move the condenser under the tank. When and not if it fails it' s easy to change out. Mount two that way when it fails in the middle of the woods gets youbackto the pits. Moved mine 3 years ago and doing so saved me a long push back twice now.

I think for now I will have to wait and see about when I can get back on the bike. Believe it or not but my Ty175 is down to 150 pounds now after 5 years of work. So I think I will stick with it. One of the perks of being a toolmaker. My Doctor is not motorcycle friendly and when ask about getting back to riding he said I should never get back on one of those death machines. So you can see why I asked on here.

More info was asked for so here it comes. 4 weeks post op. I'm from the orther side of the pond from most of you, the USA. I have been riding trials for over 40 years. Now on a ty175 in vintage class and rebuilding a Bultaco m49. Had my first heart attack 10 years ago and have had 4 more leading up to the bypass, with 6 stents alone the way. A total knee replaced 3 years ago. So I could keep riding. Not on any blood thinner, my blood does not want to clot on it own.

Thanks for the responses. Good to know I may still be able to ride again. Guess I don't have to sell the bikes just yet.

As the header says, is anyone able to ride again after having heart bypass? Just wondering if my riding trials day are over?

Yes the ty250 forks and triple trees are a straight swap into a ty175. Do yourself a favor and change out the ball bearings and races with new races and a set of taper bearing. You can use the ty175 triple trees but they will need to be bored out for the ty250 . I run my setup with 1inch of preload and 10W oil at 165 cc The ty250 forks are a great upgrade from the stock forks. Much better in stream beds and over the rock beds.

I would check the timing and the reeds. If the timing is way out it will not rev, broken woodruff key broken?

Thanks for the reply JC2 I finally put the DT cylinder on and used the TY head. The TY head had already been turned down in order to rise the C.R. And reshaped the combustion chamber. I could not help getting the die grinder out and raising the exhust port 2mm and working on the transfer ports as well. The intake runner and intake port got about the same as yours. I to had to richen the 24mm Mikuni flat slide, by rising the needle one and going up one size on the pilot and main jet. The timing is set to the same as always with the points opening at .110 inches before top dead center. All I can say is the engine is better then it has ever been. Pulls strong right off the bottom and revs to the moon and keeps right on pulling. I'm now able to pull 3rd gear on the big hills that I could not before get up in 3rd or 2nd. I was thinking about taking some height off the stock flywheel but now think I won't. I am looking for an ign system that will advance the timing as the revs build, as I think with a little less advance at the bottom it will pull just a bit better down low and still rev and pull at the top when the ign advance

Right after it stop running, pull the plug and check for spark. A coil breaking down will give spark when cold and as it heats up, will short out and you lose spark. Cools down and then will spark.

Thanks for the info guys. I think I'm going to try the DT cylinder a little more top end I would like and is what I'm looking for. Always want more power.

As anyone tried a DT cylinder on a TY175? I have an early DT jug and I'm thinking of using it. I did find that the exhust port is 2mm higher in the DT then the stock TY cylinder. And that the intake port is 3mm wider as well. Also the DT cylinder head also has a smaller compression chamber in it, but will need the fins cut down to work.

I find that a squish of .040 inches works well. Also reshaping the combustion chamber is a big improvement. A lot of videos on doing this on utube for a Yamaha Blaster. The stock head is cast and is not the best. When chucking the head in a Lathe and checking the run out you will see that most of the heads have a run out of as much as .180 inches.

There are fake NGK plugs out there. I have run into them in the past before I found out about them. They would fire out in the open, but when in the cylinder would not fire. Try googling fake NGK

Sure sound like it not getting the fuel it needs. When pulling the fuel line to the carb the fuel should run out in a steady stream. Not drip drip. If running good from the fuel line, that points to a carb problem. Will it stay running with the choke on? Try put A tube on the pilot jet hole and blowing threw it with your mouth, as stated above the jets can be clean but the passage way can be blocked. Also try to blow threw the feed line to the carb and make sure the needle for the flowed is not sticking. I had one that had a glob of junk behind the seat for the needle. Between the the in feed line and the needle seat.