Seems strange to me that you have made 4030 posts yet you're still considered a newbie.
Yes something weird happened a few years ago that changed that. It previously showed if you were a financial supporter of Trials Central or not. Now we are all just Newbies!
In Australia, riding Motorcycling Australia sanctioned trials competition events, helmets are required to meet the same standards acceptable for on-road motorcycle riding, which in Australia includes helmets made to European standards, Australian standards and the popular USA standards Snell and DOT.
There are helmets available that sit on the top of your head that are legal on Australian roads and they would therefore be legal for use in MA trials competition. Here is an example of such a helmet
Once all the video shots are done, I can drop back to a ratio that will give good longevity. For now, I must reduce the smoke.
Modern premix and injection two stroke oils for road use are designed to be "low smoke" to avoid making visible emissions and they achieve this by resisting burning during combustion of the fuel, but the penalty paid is that they condense/accumulate within the exhaust system as a gooey liquid.
If the fuel/air mixture is well managed on your Alpina and you run a modern premix oil at 40 to 1 or 50 to 1, the exhaust gases will be invisible. If you want to get the best fuel/air mixture control, run with a new modern carby jetted correctly. I run a 26mm OKO from Mid Atlantic Trials on my Alpina and it runs super sweet with perfect jetting straight out of the box.
Further to what Woody said, having just converted my series 1 (1968) model 49 to having the later type magneto cover, I found that not all the later clutch cover types (with an adjusting plug) provided enough side clearance for the clutch spring adjusting nuts. I was just about at the point of replacing the clutch hub with one with shorter clutch spring pins, when I found a clutch cover that was the same shape inside as the original 1968 type clutch cover except that it had a pushrod adjustment plug in it.
My point is don't assume that a later (boot-heel shape) clutch cover will necessarily fit over the clutch spring retainers in your Lobito. It has a better chance of fitting if you have the pin type clutch spring retainers.
I found the clutch action with the original worm drive actuator was quite good (with aftermarket clutch plates and just enough spring preload). I changed my magneto cover to the later type so I could fit the model 49 motor in a later model frame with side frame rails under the motor. With the clutch cable retainer underneath, it interferes with the left side lower frame rail on the later Sherpa T/Alpina frames.
I’m really struggling with the sport and it’s taking me so long to get to grips with the basics it’s starting to get embarrassing.
One thing I am noticing as I ride with peeps on 250 and 300cc bikes is that I have to ride my bike differently - I’m just not entirely sure what to do!
What advice would you give someone riding a 125 that would differ (or even that’s the same!) as the larger CC.
For example: my friends 250cc will just track up a (not particularly steep) hill with a smidge of throttle, my 125 would need more oomph at the bottom or it would be touch and go if it made it up.
Judging how much oomph for obstacles is a skill that comes with practice, no matter if it's a 125 or a bigger engine. The concept of riding a 125 to start with is that the relative lack of power helps you to more quickly learn good riding technique.
As for jumping up things, it is safest to initially "over oomph" things then reduce the "over oomph" progressively until you oomph "just enough".
Can anyone explain what the the two small springs in the Suzuki Beamish forks do? The bottom of the damper rod is fixed and the valve [ ? ] at the top is retained in the top position by a circlip so there seems nothing will move to act on the springs which can then float up and down on the damper rod, making them superfluous. Or am I missing something???
Think about what happens as the forks extend. Those little springs cushion the end of the fork extension travel. They are important when riding up steep hills.
It's a 2-stroke engine, if the crank case is not sealed from atmospheric pressure your engine would not operate.
No argument about why two strokes need crankcase seals but we are not talking about crankcase seals, we are talking about seals for the internal parts of the crankshaft main bearings. Rubber - sealed bearings are used to help the bearings last longer in motors that have poor ventilation/lubrication of the crankshaft main bearings.
The plastic float needle in those carbies does not give a reliable seal and can become roughened where they touch the seat. To see the roughness I need to use a magnifying glass and good lighting. However while that can cause fuel to fill the crankcase overnight if the fuel tap is left turned on, it will only be a tiny trickle, not a gush, and if the tank tap doesn't pass, is generally not an issue.
Maybe test yours with the float bowl removed and you holding the float up when you turn on the fuel tap, to see if that reveals what is going on.
My first thought is that perhaps your tickler is touching your float
Not even TY175 forks? what are the differences? is that a common and good mod or not?
You really know your TY's
I confess to being a twinshock trials bike train-spotter.
TY250 forks have 34mm diameter tubes and TY175 forks have 30mm diameter tubes.
TY250 forks overall are about 20mm shorter than TY175 forks, which is fine on a TY175 because the standard setting on a TY175 has the tubes about 20mm through the top clamps.
The clamps are the same for both apart from the size of the holes for the tubes.
Yes it's a common and good mod.
I don't have vernier caliper eyeballs and it can be hard to measure fork tube diameter using a photo, but I could easily tell with yours because they look to be bigger than 30mm and TY250 fork caps have an internal hex and TY175 caps have an external hex and the sliders are the right type.
From the photos it looks like it's got a mixture of brake backing plates and wheel hubs from various DT175 models and TY250 twinshock forks and triple clamps. All quite suitable for trials use.
The frame number means it is based on a competition TY175 model frame from 1977 onwards.
Maybe take the magneto cover off and see if someone has fitted a TY175 flywheel and ignition. They can be made to fit under those plastic covers with a bit of trimming of the cover and the flywheel weight.
So it looks like you have a TY175 rolling frame with 1978 DT175E wheels and engine.
If you post photos of the complete bike and at least the first half of the frame number it will allow for an ID of the frame and the other components.
As for the gearing, one of my TY175s had a 1981 DT175G motor (which is very similar to your motor) in it and first gear was fine for trials sections but second gear was like third gear on a TY175. It would be easy to get your first gear to work well for trials by selecting a suitable front sprocket, probably 13T with the 60 rear. I think mine with the DT motor was 12/54. Putting a TY175 gearbox into your engine is a lot of work and expense and if it was mine, I wouldn't bother because I don't use anything but first gear in sections and the DT gearbox makes it much better to ride between sections and trail riding.
That DT175 motor is actually pretty good for trials use. The porting of the DT175 motor is pretty much the same as the TY175. The port timing is the same but the ports in the DT motor are more squared-off in the corners. The DT175 motor has higher compression than the TY175 which is something that some people do to TY175 motors to get more grunt. The standard carby on the DT175 motor works fine for trials. The biggest difference in the motors is that the DT175 flywheel is a fair bit lighter than the TY175 flywheel. Some people lighten the TY175 flywheel and for experienced trials riders the DT175 flywheel would be fine. For novices it would be a bit easier to stall with the DT175 flywheel.
OK based on you posting photos showing the backing plate at both ends of it's rotational adjustment range, I suspect that you might not be approaching the task the right way. Maybe I'm off track here.
How about you say what you have tried doing so far and what the status of the points is? Are they new? Are they the existing points that worked OK earlier?
It's more that the larger bikes are more vicious, which holds back learning technique. I have a 175 (with a whopping 12hp), a modern 250, and an old 350 ... out of those the 175 is the best for actual competition because it's easier to "finesse" in a tight stop.
I've told countless people the same thing but I suspect that some people would rather have the excitement of riding on the ragged edge than getting the lowest score
Yes as long as nothing protrudes inside as it could damage the stator.
It's a normal thing to undo the nut with an impact driver/rattle gun.
As for tools to ergonomically hold it still while you tighten the nut, an adjustable two-pin wrench works on just about every magneto flywheel I've had to work on. I find it better than a strap tool.
Looks like it, but not. 100% confident that hasn't happened.
That sounds logical to me. Under that scenario the Putoline may not be a cause. It could be that given the quantity of oil in the exhaust when I got it, the rings stuck quite early due to excessive oil, then the Putoline goo was a consequence not a cause.
Or the Putoline could be crappy.
Or I just might need to go for a solid blast from time to time to keep things clean. That seems a bit odd - my riding spots are several km apart on hilly forestry road so it gets a reasonable run most days. But I just tootle along usually, maybe more speed required.
Sustained steep uphill does a great job. One of the places I ride has a decent hill with an incredibly steep concrete access road to a phone tower on top. The climb provides about 90 seconds of sustained load on the motor. Third gear on a trials bike.
I like the replies you got from the oil supplier. It's good to know that they know about trials bike issues.
The rings stick in their grooves due to gum which is made of partially-burned two stroke oil. The rings then don't seal against the bore which causes lots of ring blow-by. The blow-by then forms a gum on the bore. When the gum cools it gets even stickier. All standard stuff for a two stroke that uses modern low smoke premix oil and doesn't get ridden hard enough to burn the oil fully.
Either use oil that burns better or ride it hard once in a while or pull it apart and clean it out more frequently.
I've ridden a friend's '21 Scorpa 250 in sections and it steers and handles great and is very easy to balance on and the brakes work great and the suspension is lovely and the motor, which has a higher compression head, is quite responsive but easy to manage. The footpeg location feels great too and the clutch is also very nice to use. The bike also feels very light to ride. I like riding Shercos too.
The owner of the Scorpa is pretty much exactly my size (5'10" 95 kg) and I can jump straight on it from one of my twinshocks and it instantly feels good and easy to ride so I would say that is a sign of a forgiving modern bike.
Thank you guys very much, I'll give the bearings a shot since I have the original steel inner bushing/tube. Ordered some shocks and misc. pieces as well, shipping from the uk is painful but I can't wait to hop on this bike again. The dualsport just doesn't cut it when it comes to playing around in the woods and climbing obstacles and I miss the sound of a 2-stroke so much.
If your inner bush is worn or pitted, it will not work well with rollers
If you can get a properly hardened inner bush for the rollers to run on that that kit would probably be OK. I bought a similar kit to the one in you link a few years ago and fitted it along with a new (aftermarket) inner bush, but with only a little use, the rollers wore through what turned out to be very thin surface hardening.
I think they would be fine with a new, genuine Yamaha inner bush
The standard TY175/250 plastic bushings fit a very wide range of Yamaha models
Thank you for that information. I did not see any timing marks but that is just about where I marked the flywheel and case with a felt tipped marker. I picked that area because the nut on the flywheel case lined up very close to the edge of the case. I will have to take a closer look tomorrow and see if I can see the marks near there. What I did was exactly what I suggested in my previous post. I brought the piston to 3.1mm BTDC and made a mark on the case and flywheel. Thanks again.
LaVern
P.S. Is there a way to get emails informing me of replies to my postings? I just happened to come back to this forum and saw a reply was made 7 hours previously.
LJS
re P.S.
Yes. Go into your account then "settings" then "other settings"
I enquired about a used Sherco Yesterday re the fuel consumpion time , it was over 200 cc , they replied over 3 hours to a std tank , does that sound right ?
It's so variable depending on the sort of riding in the three hours, but if that figure is for riding in a competition trial with a short loop and queues at most sections then it sound about right.
Trials engine manufacturers
in General Trials Talk
Posted
Depends on what you define "manufacture" and "in house" to mean.
Yes. Some brands share engines with other brands. Current examples are Montesa/Honda and Sherco/Scorpa.