Yamaha

Where do i start!? It runs and rides. 1. The previous owner has the throttle cable going into the case but mixes fuel. I was told replace rhe whole control with a domino and run the cable directly to the carb. What cable do i buy? 2. What ratio and premix type? I run motule 800 80:1 on my modern bikes. 3. What fluid do i put in the transmission? 4. Forks seals leak. Should i order oem stuff or is there a better alternative? 5. Bearings! Do i use oem or is there better? 6. Sprockets and chain. Where do i get these? These are my "initial" questions. I plan to use thia bike for sime vintage competitions. I would like to m…

I have a Yamaha TY250 Twinshock around a 1974 -1975 it is in mint condition with only 500 miles on it. The bike starts no problem and sounds good it's only when riding and at 3/4 - full throttle that it seemd to start pinking and looses power. I've had the carb out countless times and cleaned it also checked the reed valves, air filter and the exhaust and there all fine someone mentioned it could be a timing problem but i'm not sure I love this bike but and want it fixed Anyone any ideas?????

Guys, So after getting my parts back from Millenium Technologies- new bore on Ebay cylinder and new piston- I noticed quite a bit of vibration. So today I tore it down again and weighed the new piston, pin, upper end bearing and compared those weights to the ones on the original parts. As I expected, the new piston was significantly heavier than the old original piston, even though the piston size was still the same. Old Piston 213 gm New piston 241gm a delta of 28 grams. Old pin 57 gm New pin 60 gm delta of 3 grams The remainder of the parts were too light to measure on the scales I borrowed, so I am forced to ignore those …

I have started restoring a 1975 TY80B that I recently purchased. First on the list is to repair the bash guard area which has been damaged and badly welded up. I'm not fully sure how to approach it at this point, but I'm thinking I need to cut out the guard plate, then try to reform the crushed C-section pressings on either side. To reform them I intend to get some round bar the same diameter as the inside of the C-section, bend it to match the bend to the down-tube, then heat up the C-section and press or hammer the bar into the section to reform it. Then i may weld some tube in to strengthen it. After that I use a bolt on Aluminium skid plate. Has anyo…

Hi all, so? Ty80 forks were knackered so in the usual spirit of repair rather than source a replacement which are often as knackered as the ones I've got i sent them off for Re chrome, straighten and rebuild with new seals. It took months to get them back, so all looked good till the first ride and son says they are locking? They are not moving up and down? When completely compressed back in the garage they knock side to side so I diagnose worn bushes, are these still available and from previous threads I see you can remove the spring clip and slidehammer the whole lot out? But there's a screw in the bottom of the fork leg which I thought held the whole lot together? I d…

Hello, I bought a TY 175 Road Registered brand new in 1980. I just bought another yesterday that looked almost the same but with no lights etc. and this one had never road registered. I remember stripping mine down and painting the frame red in 1981. I remember going to shirts workshop when they were building the Majesty's but could never afford one at the time. This one was advertised as a good runner!. After getting it back and attempting to get it running. We ended up stripping the fuel system. Tank off and flushed about 20 times to remove massive amounts of rust buildup. Carb off and cleaned out no damage to needle or slider jets etc. Std 240 Main. We coul…

Hi all, I got a TY and have been loving it. At our Trial last weekend it started bogging off idle. I cleaned the carb tonight and when I checked the idle screw it was only a half a turn out. I always think 1 and a half turns is closer to what I use as a standard starting point. I am going to be competing this weekend and just trying to get some input for when I try to tune it up at 8000 feet. Opening that screw is leaning it out and would be the right direction for higher altitudes,Right. Raising the clip one notch will also drop the needle and help also, correct. just need some reassurance as I need a good running bike to compete with these guys that have 7000 dollars in…

Hi everyone, I just finally got my son a ty80 that was partially restored. The bike is leaking fuel from the carby, I hope that it's just the float being stuck, does anyone know if this is a common problem? Also, both clutch and brake levers seem a bit too big and hard to pull, does anyone here knows of a suitable replacement with an adjustable screw so that would bring the whole lever closer to the bars? I'm not really after shorter levers as they still need to be long to be pulled confortably. Do you know where I could get a side stand? The chain seems VERY loose, I either need to take some links off, or put a bigger sprocket, and I'd probably …

Hi All, Hoping someone can help... I have a 1978 TY250, but it's very flat when accelerating from the bottom. I have taken the flywheel weight off and that made a difference, but it's still quite flat and needs livening up. Any suggestions? Many thanks.

Hi All Would anyone know what was used for the headgasket on the 320 Majesty's.

Thanks again for the info you've all given me on me last guestion. Now here's another. Do i just disconnect my autolube system if I want to premix my fuel. And does any body know what the oil,petrol mix would be. Sorry if Iam being a pain. Squid.

Well my rebuild of this little motor is done and back in the frame. It starts first kick and has a good spark but Boggs down in neutral when I twist the throttle. adding choke helps a lot but still Boggs when out under the slightest load. once warm it will bog down with or without choke on acceleration. ill change the fuel tomorrow and maybe check the plug, maybe pull the carb and check float height and jets any other ideas welcome please thsnks ron

Well, more seal problems- the All Balls seals jammed half way into the seats on the fork tubes and had to be removed. I made a male plug the same size as the fork slider and plugged up the bottom end with a threaded thick aluminum washer. this lead out to another washer on the outside bottom end and another nut. this sealed up the bottom end and I poured the fork leg full of water. Then with the fork tube in special jaws on the vise I put the male plug thru the seal and it rested on the water inside the tube. the seal kept the water inside when I hit the top of the special plug with a hammer. After a few whacks with a 5 pound mallet, the seal was pushed out fro…

I've bought a TY250 Mono. I took the engine out to paint it, but now the clutch lever arm is not pushing the pushrod to activate the clutch. I can remove the lever arm and see its a cam profile. There is marking where it pushes the rod and it's not excessively worn. My mechanical knowledge and ability is far behind many of you on here, so I'd appreciate some advice on how to sort this. Thanks Dave

Hi all, I've just rebuilt the engine on this 1980 TY80 and just put the crank cases toghether again along with clutch basket pushrod, primary gear mesh and shift mech. I have a couple of questions I hope you can help me with 1) The clucth basket outer will rotate anti clockwise which drives the crank clockwise but when I try to rotate the clutch basket outer clockwise it will go 1/4 turn before stopping. Is that normal ? 2) Should I be able to use the gear shift mech to select all gears by hand at this stage ? Thanks in advance.

just picked up a 75 TY175. It has footrests that are bolted on the lower part of the frame.. below the kickstarter/CS sprocket. I see that there are kits to move them back, so I assume that was a factory option for these bikes? (I'm just starting to learn about these bikes so please bear with me). secondly, and more importantly, I see what look like a couple of different kits (or maybe they are all the same?) but wondering if I need to also replace the shifter/brake lever? I've ridden modern trials so I am used to the shifter being well forward of the left footrest, but wondering more about the brake lever.. it looks like the stock lever will require a bit of a s…

I always wondered what the difference new shocks on a twinshock would make as far as handling etc. The stock shocks on my ty250a would sag the rear and bottom out easily but at the same time be quite stiff almost like running struts. I know most would recommend Betors, Falcons etc. but the $200-$400 cost just is not going to happen. So I came across a set of shocks from a 90's ke100. They had a what I would call a "looser" wound spring than the stock springs and were longer. Reviews of a ke100 said that the shocks were 'Bouncey". Anyway $25 dollars later and some drilling out larger of the bottom bushing they fit nice and do not have the sag in back. They are bouncey an…

Hello, I just bought a standard piston kit for my ty 250 88, but after trying to fit it I realised it was too big the piston is 70mm, but the bore on my cylinder is 67mm is there anywhere that sells a 67mm piston? I can’t seem to find it anywhere thanks, Dan

As in many clutch baskets there are rubber bushings with in that help with the engagement. Well one of my TY's has had a pretty loose clutch basket. I have searched high and low for a rebuild but alas I could not find anything. Never to be deterred by a challenge I decided to give this idea a go. I can't vouch for its durability but here goes nothing. Preface: I silicone mold parts. I can't stand paying someone for something i can do myself. With that being stated I decided to try silicone molding my own customer bushings in the clutch basket. Step one: I cut off the heads of the rivets that hold the clutch basket together and pushed them part way through t…

I notice on some TY250 the left hand crankcase cover has been cut down to expose the front sprocket, I presume this is to make it easier to change the sprocket without disturbing the electrics. Two questions am I right and secondly is there an optimal position to cut the case? I have a 1974 model. Thanks for any help