feetupfun

Here are the M49 Series 3 photos. Serial number is M4902517. I put the handlebar clamp photo in because I wanted to show why many people replaced the top steering yoke on their M49 for one with a better clamp.

I visited a bike boneyard to look at two M49s and luckily they were examples of a series 2 and a series 3 bike. This posting has the photos of the series 2 M49 serial number M4902195 and the next posting shows the other bike. What got me motivated to go looking was a post by Woody: "The serial numbers are from Bultaco's own figures so they should be right. However, they only list the model 49 as having one frame change during its production run but there were two. Series 1 with single tube under engine, upright shocks. Series 2, single frame tube under engine, angled shocks with seat unit altered to accomodate relocated top shock mounts. Series 3, twin frame tubes under the engine, like the M80 and which was the basis for the Kit Campeon."

Way less than 33 BHP. I would estimate about 15 BHP.

There are no hard and fast rules for this. One of my friends only ever uses first gear for absolutely everything (250 Majesty) and another only ever uses third gear for absolutely everything (240 Fantic). If you can develop good enough technique with the clutch, you can use a higher gear than if you are a bit gumby with the clutch. That way you can use second or third even in tight stuff and still have great speed potential for big ups. Another thing is that if you get your bike running so it revs out cleanly, you can get high ground speed even in first gear. This is one of the technical advantages of a well set up four stroke - they generally have a greater range of useful RPM than a two stroke.

Many years ago when petrol could be stored for weeks and seemed to work well, it was drummed into me that it was important to leave the addition of the oil till the last minute for the best results from the brew. With the pump petrol we get here, it goes to crap so fast that it is now quite irrelevant when you mix in the oil. If straight modern petrol or premix is more than 2 weeks old, it goes into my car fuel tank.

I've found you can keep things under control better during the straightening if you leave the axle in place - this reduces the risk of the arms being bent sideways. Another thing is that to do the bending you can usually use a bar positioned under one arm and over the other rather than a bar on each arm. Some bikes you can get the bar in position with the wheel still in place but for some others you will need to make a spacer up to replace the wheel so the axle can be left in place tight. Depending on how difficult it is to clamp the bike down, it may be easier overall to make a fixture to hold the swingarm and swingarm axle while you straighten the swingarm. Last one I did the frame and the swingarm were both twisted so I made a fixture that clamped the bike via the swingarm axle ends so I could straighten both the frame and swingarm at the same time.

Yes the 1970s twinshock trials bikes are fine to commute on. That's what lots of people (including me) did with them when they were new. Some are more comfortable than others. If you are talking standard seating, the most comfortable standard bikes are OSSA MAR, C, D and E model TY250, all TY175, TL125, KT250, Mk 2 and 3 Cota 247. Standard Bultaco Sherpa Ts and Cota 348/349 are at the ouch end of the spectrum. Any of them can be made much better with improvements to the seat foam and cover. I have put nicer seats on my M49 Sherpa T and TY250A and can ride them all day in comfort sitting down. Here's a picture that shows the difference. The TY250A has a slightly thicker seat and the TY250B has a standard seat.

I think it would have been good to take the bend out of the top frame tube while it was apart.

I've seen a TY with a shortened muffler from a Suzuki RG250 (1980s twin cylinder 250cc road bike) Any YZ/RM/KX/CR two stroke end muffler should work with mods to make it fit the TY. The main mods are to make the pipe the right shape to fit past the shockie and provide clearance for the tyre. Ideally get a muffler from a bike that has the pipe on the inside edge (when fitted on the RHS of the TY) to maximise tyre clearance.

Yes a guy in my local club recently modded the steering head angle on his TLR250 and reckons it is better. Don't know the angle he aimed for but you may get the answer from him on this forum or if you post ont the trials.com.au twinshock forum. I know he cut and rewelded the frame at the steering head. If you do similar you will be reducing the wheelbase and may get more grip as a result.

(the 247 with the aluminium guards) Top shock mounts moved Edge grip strips fitted to footpegs Maybe rear frame loop bent up a smidgin 348 style front mudguard mount A decompressor and a partridge in a pear tree

The only ones I've seen for TY80s are the Betors that John Cane sells. I haven't bought any yet but logically they would have to be light years ahead of the standard TY80 Yamaha shocks.

If its the same thread size as an OSSA you can buy them (aluminium inserts for welding in place) off the shelf from Keith Lynas in the US. I will go and check the sizes of both. Yes I just screwed an OSSA header nut into a Bultaco M27 barrell - perfect fit.

Sounds to me like at least one gear has siezed. Thats all it takes to get your symptoms. Hardly unusual if ridden without oil. You won't know the complete extent of the damage until you split the cases.

No its not true. I just bought a piston kit for my 250 MAR and was offered a choice of two brands by Keith Lynas in the US.

Dave I will be getting the numbers from two more M49s just after Christmas at a rellies place which may help with when the changes were made for that model. I think one is a series 3 and the other series 2. David M49-00100

My Dad was a road bike rider from his teens, only having a rest from bikes when he had to build a house so he and my Mum could raise kids. When my sister and I were old enough (in about 1968) his bike passion took over again and he started fixing up old bikes for himself and us to ride. There was a 100cc MANET scooter, a 125cc CZ road bike, a 16H Norton with sidecar, a Tiger Cub and an early Yamaha 80cc road bike (G1FD). I became hooked in a flash and by 1974 I had a TS185 which I then modified for Trials so I could ride with a kid from school who had a proper trials bike (RL250). I soon learned that the TS185 was hard work in sections so bought a M85 Alpina, which was only a bit less hard work. Practice was a daily thing after school at the local bush and that place was also used by the state trials champ of the time for practice so I had a pretty good guide to what was possible to do on a proper trials bike. This led to buying a TY175B second hand in 1976 which was like a breath of fresh air to ride compared with the Alpina. I rode that TY175 till 1980 when the girlfriend thing became too much of a distraction. Then it became a wife thing and it wasn't till 1988 that I rode trials again. The Ty175 was still quite competitive at that time but it was getting very worn out and I kept hitting brick walls trying to buy parts or even parts from wrecks to fix it. Long distance Trail rides and Enduro competition took over until about 1994 when I learned of the VMX and Twinshock Trials movement and I got very interested in trials again. I bought the first going twinshock trials bike I could find (a TY250A) and rode a state titles event and loved it - riding against other old bikes. Things then sort of spiralled upwards out of control as over the next 10 or so years I bought every Twinshock trials bike I had wanted as a kid (most of them not going) and brought them back to life. The arrival of the internet in the late 1990s made it incredibly easy to get old bike parts and it keeps getting easier. By 2006 I had gathered all the twinshock trials bikes I wanted except a 250 Yamaha Majesty (they are very rare in Australia) and had contacted people all over the world trying to get one and tried to borrow an original to make replica Godden Majesty frames locally. Later that year I got THE phone call from a guy in Western Australia who was ready to sell his unused Godden 250 Majesty frame kit. At the time I had made plans to make a replica of the first Majesty 250 (the one that is made from a TY 250 frame) and was very close to starting. Soon after getting my Godden Majesty going new replica Majesty frames became available which is just another example of how things have improved as far as being able to buy parts for the old bikes. I keep most of my twinshock trials bikes close to standard for the purpose of being able to compare what they would have been like to ride in their prime ie not moving footpegs, shockie mounts, fitting different forks, doing frame chops or swingarm extensions. One exception is a TY175 that I like to try all sorts of mods on and has become a bit of a beast. It is great to be ride the bikes back to back and compare what I feel to what the magazines of the day said about them and to hear other twinshock riders opinions about how they compare. Riding twinshock trials has become quite popular here but is still nowhere near the fanatical level seen in Spain - here it is mainly riders who started their trials riding on twinshocks in their youth and still love riding them.

If the problem started all of a sudden, it could be an ignition stator problem. The symptoms you describe are what mine was like to ride when the stator failed.

Look on the bright side - at least the clutch plates aren't stuck together.

I had to take that gear off my 348 and I'm assuming your 247 has the same sort of taper. I found that a gear puller with fingers couldn't put enough force on so I made a tubular puller that has a full circle shoulder that goes behind the gear. It is made in two halves so it can be fitted over the gear, then the two halves are held together for the pull. It worked. I think that sort of puller is available from Montesa specialist Jared Bates or can be made with a welder and lathe.

Tony there are other Ty175 models than the 525 prefix models. There is also a Ty175 model that has a frame like the Ty125 and has prefix 1N4. Not sure where else they were sold but they were popular here in Australia as they came fully set up for road registration while the 525 models only had basic lights and a (relatively) noisy exhaust. I guess the LH sidestand was for road registration requirements in some countries. david

One way to be certain is to measure the diameter of the bore. If it is 66-68mm, it is a 175. If you are tricky enough you might be able to make this measurement through the exhaust port with the pipe off. If it has the original barrell, you should be able to tell what capacity it is from the engine number prefix. I can't remember what a TY125 prefix is but the most common TY175 prefix is 525 and the road-going TY175s here are prefix 1N4.

Yes the front hubs on TY175 and TY250 twinshock are the same. Rims are different widths - don't know why.

TY250 forks do have a better action than TY175 forks for people over a certain weight (damping and springing) and using them will preserve the existing steering geometry (being in-line axle and can be set to provide the same ride height). They are 34mm diameter though so would be too small for your bored out triple clamps. TY mono forks have a better damping action than TY250 twinshock forks but being leading axle will reduce the steering trail. A better bet would be to use TY mono triple clamps too but this requires work to get the steering stops right. Both the TY250 twinshock and TY mono forks are heavier than TY175 forks. I wouldn't complain about someone using TY mono forks on a Majesty because they are comparable in performance with the forks seen on late model twinshock bikes. We have a manufacturing cutoff date of 1987 here for twinshock bike technology so there would probably be no issues. I've seen TY mono forks and front wheel working quite well on a heavily modified RL250 too.