To have so little flaking after all these years, you have got a good one. One of mine on a 1975 bike is still perfect while another on a 1978 bike was terrible and had to have a liner fitted.
From memory your bike is a 115 or 116 which may have the type of rear hub that came with a ferrous liner from new.
Before you ride it you will need to fit the frame braces that are missing in your photos. They connect the outside swingarm pivots to the lug on the rear edge of the cylinder head
So what are the advantages of a "radial" tire? I know that tube less is not going to work and I need a trials tire to be able to get into some novice vintage events for my 74 TY 250A.
It also has to work with the Dunlop 803 GPF -21 that is on the front end. That tire is a tube type for sure- the words are made into the side wall rubber.
This is getting confusing- I was back on the Chapparral web site and looked up the TR-11 tire there and it said it was "tubeless" again. Does IRC make both tubeless and tube types in the TR-11?
looking for a 2nd oversize piston for a TY250 twin shock can anyone help
New piston kits are available. They are usually in the manufacturer's catalogue as YZ250 or DT250 or MX250 rather than TY250. Wossner make a good quality piston kit for them. You may need to source a little end bearing different to the one in the kit depending on what conrod is in your motor.
I would think that using a ball hone in a 2 stroke cylinder would pretty much guarantee an uneven honing pattern, so there would be an unusual visual effect from the rings on the hone marks.
New 2 stroke rings usually take 10-20 minutes of gentle operation to bed in, spread over 4-6 heat cycles.
Unless you are seeing darkening of the bore surface due to ring blow-by, I wouldn't do anything except ride it.
No it won't arc across between kill switch contacts. It is low voltage and a proper kill switch is designed to do it's job. I've never measured any but I would expect it would be less than 30 volts.
First off you need to test if the kill switch is actually working or not. I suggest you measure the resistance through it with both wires disconnected from everything else.
We have to use lanyard killswitches for trials competition here and popular lanyard kill switches are made by Leonelli and Jitsie and have a magnetic action
All my bikes require the killswitch to earth out the LT circuit of the HT coil to stop the motor. These kill switches I mentioned have two wires and either of them can be used to connect to an earth point. It's best to run the earth wire from the kill switch to an earth point on the main frame of the bike, to avoid sending current through the steering bearings, which could otherwise damage the bearings. Most people connect the kill switch earth wire to where the HT coil connects to the frame. Most people connect the other wire from the killswitch to the LT wire near where it connects to the HT coil.
If the reason for your conundrum is that the gasket is acting as a weir then you can test for this by draining the gearbox and seeing if the dipstick is still showing a level
As always a comprehensive explanation , thank’s for taking the time . Is there a way of telling the year of manufacture from the engine no ?
Yes there are listings for when different models were sold but beware that the sales timing was different in different parts of the world, they didn't work to calendar years and they changed things without changing the model number, so it can get a bit confusing to think in terms of the calendar years. Here's one list that may help. There are plenty of other lists available on-line. They don't all agree.
feetup fun! Take another look at that casting pic you sent- there is a hole thru the wall - looks like just in front of the left most threaded hole boss at the bottom left corner- I looked at my pics again and I had too much ATF still in puddles to see if mine had that hole open or not- but it looks big enough to equalize the two sides if it was there and if it was also open.! And I don't think that's the same hole as the drain plug hole is it? But even if it was the same hole- when the drain plug is installed- it would block off any oil that wanted to flow thru the wall. My problem is not when the oil drains anyway- that's fine- it's only when you fill it up that the imbalance starts.
On the motor I took the photo of, the drain plug drains from both the clutch casing and from the gearbox. The drain plug hole is open to both sides. I suspect that this could be where your problem lies. For some reason your drain plug may not be draining both compartments.
Before I went and found the engine casing to take a photo of, I was expecting that there would be a dedicated hole near the bottom to let the oil levels equalise, but Yamaha have designed it for the levels to equalise via the the shift drum hole and the shifter shaft hole, both of which have rotating components that are a loose-enough fit for oil to pass through.
I was going interested in your description of your 116 Alpina as a 325 cc so I measured the stroke on my 116 and found it is 64 mm giving me 347 cc . I see from the spec sheet in my manual that there are 326 cc Alpinas with a stroke of 60 mm . When did the change occur and was production of the two different strokes at the same time ?
The first "350" Alpina (model 99) was 325cc and at the time, all Bultaco San Antonio 2 motors 250cc and bigger were 60mm stroke. The "350" Pursang, Alpina and Sherpa T were all 325cc. They didn't want to go any bigger in the bore for that stroke so that's where the 325cc came from.
When they wanted to make the Pursang 360cc instead of 325cc, the stroke was lengthened to 64mm. This required larger crank wheels so when they went to 64mm stroke, the crankcase design also changed. The "350" Alpina and "350" Sherpa T also went to the same larger crank wheels design however the Sherpa T stayed at 60mm stroke (325cc) while the Alpina went to 64mm stroke (350cc).
The 325cc Alpina (model 99) was sold in 1973. The first 350cc Alpina is the model 116 and was sold in 1973/74. Later Alpina "350" were all 350cc. However, Bultaco are reknowned for changing things in the design of a model during the production period so anything is possible (such as a 325cc motor in a model 116) which is one reason for why when you order engine parts from In Motion they want to know the engine number, not just the prefix.
Feetup fun- I will check the level again this morning, but if it is still high I will be pulling off the clutch cover and have a look- Just going off of faint memories- I think I used to be able to take on a liter with no issues before the engine overhaul. I checked the top case vent to see if it was clogged - not clogged. What do you suppose it is?
My first thought is something that is acting like a weir between the gearbox and the primary drive compartment.
There's another test you can do before taking the clutch cover off if you want. If you drain the gearbox via the drain plug and yet still have a high level when you dip the primary drive compartment, then that will prove that there is something stopping the oil level from equalising between both compartments.
If there is something acting as a weir, it's possible that whoever built the engine made their own gasket and didn't put the bottom hole in the gasket for one of the passages where the oil flows back and forth between the gearbox and primary drive.
There are also other possibilities but no matter what it is you or someone will need to take the clutch cover off to find out what is going on
Starting from a drained crank case- this morning I put in exactly 1 Liter of ATF as a test. As of 3:30 this afternoon, the dipstick is still showing about an inch of over fill. I tried leaning the bike over to the left side about 30 degrees for 30 minutes , and this seemed to drop the overfill condition so that it came down from about a 1.5" overfill to about a 1" overfill, but never did settle more than that.-
Tommorow I will pull off the clutch cover and see if I can figure out why the oil is not being distributed enough to use up the 1 liter quantity.
It would help if someone else did the same test- drain and fill 1 liter and see what the dipstick shows for a quantity????
Here is where 1000 ml comes up to on my A model. I put masking tape on the dipstick so the oil would be visible in the photo. The oil level is 12mm from the end of the dipstick. I dipped it without screwing it in.
feetup fun- that's great stuff- I have the same one and the same measurement 133 mm. Next question- how can anyone get a full 1 liter of oil to stay below the upper fill mark on this dip stick? I can only get .4 liters in and even that much will touch or exceed the upper fill mark when the engine is cold. I can't believe that warming the engine would make another .6 liters get absorbed??
There are a few possibilities for what you are seeing:
1 Not all the old oil was drained out.
2 The bike was not level when the dip was taken.
3 Not enough time was allowed for the oil to flow out of the primary casing and into the gearbox before the dip was taken.
4 There is a problem with the oil flow path between the clutch casing and the gearbox (maybe gasket covering the passage).
OK- with the help of Magesty- The torque setting for the 4 aluminum hold down bolts in the cylinder are listed as 4.2 to 4.5 m-kg this comes out to 30-32ft pounds of tonque on those aluminum tube nuts!! That seems like a lot to me- Soound right to you ?
I figure that some people don't do them up tight enough because on a TY250D I bought, it developed a base gasket leak that stopped leaking when I re-tightened those nuts
The 250 is 10kg heavier than the 175 because the 250 motor is 10kg heavier. The 250 feels light for a 93 kg bike which is a normal weight for a standard 250 twinshock.
They didn't sell so many Yamahas by accident.
They were designed to appeal to Clubman riders and they still do.
The 250 is 16 HP and the 175 is 12 HP. They both pull well and in proportion to their capacity. They both have a ridiculously wide useful RPM range.
The 250 is a short wheelbase and the 175 is an extremely short wheelbase.
All mods are entirely personal preference. Both are very good to ride stone stock.
Many people lengthen the 175 to get a light full-sized bike.
Help identify frame
in Classic Trials
Posted
I don't know what it is but it is a beautiful design and well-made