Trials Australia Forums

Greg Harding wrote:Hi Everyone,

The :Honda: TLAh mudguard is plastic, here is how it came to me:

1628241900201.jpg

Pretty sure it is genuine :Honda: from one of these:

1628242018680.jpg

Does this photo help you understand?

1628241479076.jpg

Still have no clue how I broke it, my usual trick is to snap them in half next to the rear mounts?

OK So it is some sort of moulded plastic then.
There's a cool tool I've seen advertised recently that heats up WWWWWW shaped pieces of steel strip and embeds then across breaks in plastic panels just like yours. Would look like surgical stitches but would be strong (and very cool, like surgical stitches). I'll see if I can find a link

Here are what the WWWW things look like and there's a heating tool that holds them so you can push them in while they are hot. I think the whole kit including the tool is about $70
https://au.banggood.com/100Pcs-Hot-Stap ... &ID=522934

Phil[/quote]
Phil, can you be a little more specific? Is this what you mean.

This what I use to bond plastics together.
It looks to dissolve both surfaces and they then join together as the adhesive evaporates.

Tried to attach a phot, but my iPad is not cooperating.
I use Humbrol, Liquid Poly.
Available from modelling shops.

https://www.australianmodeller.com.au/p ... iquid-poly

https://www.sydneysolvents.com.au/MEK

Golden Flywheel Thoughts

I assumed LG2 Bronze would be what they would have made it out of (Cheaper than most bronzes) - Which density is 8830Kg/m3.
Steel is 7850Kg/m3 which is approximately 10% less.

Inertia = Mass X Radius^2 for a flywheel.

The diameter is the dominant term but if an equivalent mass flywheel was used you would have to increase the diameter of the flywheel because of the reduced density to maintain the inertia if you made it out of steel.

The only other reason I can think of is it would make it easier to fit the magnets to the rotor if it was made out of Bronze, being non-magnetic.

I would say it was made of Bronze simply because its easier to cast than steel. Most magnetos seem to be made of Cast Iron with a steel centre piece for mounting purposes

After fixing the sticky KT250 float needle a couple of weeks ago, I rode a trial last Sunday and the ran unevenly at times.
While the carby was apart cleaning the gum off the needle valve before that trial, I did see a bit of wear on the needle but didn't have a spare needle kit handy so just rode with it and so I wasn't that surprised that it didn't run that well.
So last Sunday night I ordered a couple of needle kits from the Mikuni agent in Townsville. They posted the kits off on Monday and Australia Post amazed me by delivering them to my house near Gladstone on Thursday. That's three days in transit which is faster that having things sent from Brisbane to here.
Here's a photo showing the wear on the needle. I've had to replace so many of these needle kits in Mikuni carbys over the years that to me it seems to be a bit of a weak point in their design. My bikes do a lot of hours travelling in a trailer but I usually run the fuel level down in the carby before loading them, hoping to minimise the wear.

After rebuilding the KT250 motor, I had to deal with clutch slippage from the extra torque. It was previously set up with four TY175 springs which are the same length as, similar diameter to and slightly stiffer than KT250 springs. This wasn't enough pressure plate force for the newly-rebuilt motor so to get it ready for an upcoming trial I fitted six standard KT250 springs, which definitely stopped the slipping. However this trial had two sections that benefited from using the clutch in a controlled manner and the lever pull was too much for my old body to achieve delicate control.
So I started thinking about ways to make the lever pull lighter. It already had a Ballard's high-ratio lever. I looked at ways to incorporate a lever device to further increase the ratio and also looked at fitting a pit-bike hydraulic clutch conversion but those ideas were eventually usurped by the idea of reducing the clutch spring preload. I figured it was a good thing to try because it wouldn't cost anything, wouldn't take long to do and it was also what Greg Harding suggested
Today is test and tune day so I did the float needle swap, reduced the clutch spring preload by about 20% (10.2mm to 8.2mm) and fitted a new Venhill KT250 clutch cable. I wasn't that impressed at having to modify the cable outer to get it to fit the bike.
The testing today went very well in that it won't slip even fanning the clutch in top gear and the lever action is heaps lighter. Very nice. I'm even thinking of reducing the preload further but will give it a much longer test before making another change.

David Lahey wrote:After fixing the sticky KT250 float needle a couple of weeks ago, I rode a trial last Sunday and the ran unevenly at times.
While the carby was apart cleaning the gum off the needle valve before that trial, I did see a bit of wear on the needle but didn't have a spare needle kit handy so just rode with it and so I wasn't that surprised that it didn't run that well.
So last Sunday night I ordered a couple of needle kits from the Mikuni agent in Townsville. They posted the kits off on Monday and Australia Post amazed me by delivering them to my house near Gladstone on Thursday. That's three days in transit which is faster that having things sent from Brisbane to here.
Here's a photo showing the wear on the needle. I've had to replace so many of these needle kits in Mikuni carbys over the years that to me it seems to be a bit of a weak point in their design. My bikes do a lot of hours travelling in a trailer but I usually run the fuel level down in the carby before loading them, hoping to minimise the wear.

David, I used to run a RS125 in a Superkart and I removed the carby but left it on its cable and layed it in the seat of the kart when it was being transported in my trailer.
Many others did the same thing for the reason you have.

Phil

I had the pleasure of sampling David's much modified KT while in CQ recently.

Like Chippy, I like the KT's handling. Or at least, most of it. Mine has different footpegs which effectively lowers them and rear-sets them by 10-15mm each way from standard.

Others say the KT steers slowly but the rake is the same as a TY250 and the trail noticeably less. And the wheelbase only slightly longer.

What I perceive (and don't like) is a slight 'heavy' feel to the steering and a bit of a cumbersome feel to the bike due to weight distribution, which people confuse with slow steering. It has more forward weight bias and higher C of G than other twinshocks and you feel it.

David's bike has considerably more rear-set and lowered footpegs and a lengthened backbone (under the tank) which reduces rake and trail and provides a bit more room in the 'cockpit'.

Bear in mind that I wasn't riding in a section but I found it a delight to ride. The steering has a very light and responsive feel to it and I didn't notice any of that cumbersome feeling. The whole bike felt somewhat lighter in handling and the modified riding position felt very comfortable to me (I'm 5'10")

Try as I did I could not feel any tucking under which I suspected there might be from the reduced trail.
Tho I'm lighter than David, the modified suspension still felt very supple to me.

I have been wanting to lower and rearset the footpegs on a spare frame and I am even more convinced now

Compliments to David

Today is my RDO and I decided to get cracking on my friend's TL125 tank.
Years ago my sister gave me a kit of Dremel tool inserts, assuming I had a Dremel multi-tool, like she did, but I didn't.
All the years I was a model aeroplane builder, I thought that the Dremel was a really cool thing but a bit extravagant (expensive) and not really necessary so didn't buy one.
When I looked at the welded seams on this TL125 tank I wanted to cut apart, I realised that my trusty 4" angle grinder was not going to be able to reach all of the seam. Finally, (like the 4 jaw chuck I recently bought for my lathe) I could justify in my own mind buying a Dremel.
Then came the revelation that Dremels are now much cheaper relatively than they were in the 1970s and that there was even a re-chargable Dremel that didn't weigh much. One trip to Bunnings later and I was set.

Anyway here is what the tank looks like after I separated the top and the bottom. Releasing the seam near the rear tank mount was quite tricky due to some old weld repairs someone had done there. The rest of the seam was straightforward. While grinding the rear mount end, I re-used the jig that I made to hold the tank when I initially tried to pull the top dent out from the outside.
The shape of the bottom half of the tank seems way more complex than I would have thought necessary.

David Lahey wrote:A friend gave me this TY mudguard a few years ago that he removed from a :Bultaco: model 199 Sherpa T. It is my first close-up contact with something that has been vinyl wrapped, which is apparently something young people do to cars nowadays.
I've been admiring it for a few years now, but another friend is in need of one of those guards.
He doesn't know yet that I'm going to give him a guard, but he did ask me to try and find one for him.

I'm in a dilemma about whether to remove the wrap before I give it to him or leave it on.

Please help with this fairly minor but fun first-world philosophical dilemma.

Here is some background info:
I have no idea what condition the guard is under the wrap.
I don't want to give my friend a crap-looking guard.
He never looks at the internet so won't see this posting.
I really like the look of this guard with that wrap and there's a fairly good chance he might like it too.
The orange colour on the guard doesn't match the orange of his TY175JC.

The outcome of this dilemma is that my friend ended up with an (unpainted) TY front guard and I will continue to admire the lovely wrapped guard