feetupfun

So you haven't worked out who he is yet? I'll give you a clue - he rode at the same Twinshock Masters as you and I but didn't ride the bike in question

I looked for many years for a 198 or 198A and in that time was offered countless 199s and 199As. I eventually found a 198 (thanks Reginald) which is in the process of being readied for use. I totally agree about the virtues of the 250 motor compared with the 325, for people who want an enjoyable ride.

I reckon about the same helpfulness but yours is also humorous so it gets extra points

That list shows a silver-framed M199 and a blue-framed M199A but does not answer NedKelly's question

About an inch less than the ones on my M49. You can measure them in the time-honoured Reginald way if you want. There is a new set not fitted to anything yet.

Have you compared it with another similar bike? Is it the same frequency as the engine rotation? Did it start suddenly? Is it there hot and cold? It is normal to be able to hear the piston rocking in a four stroke at some RPMs if the exhaust is quiet enough. Also possible to be noise from the valve train. Knock knock at engine speed - piston noise. Tap tap at engine speed - valve train noise. Ticking or clicking noise that happens irregularly may be cam chain noise

I just measured a couple of sets of Fred and Deb KT bars at 835mm

A man with an eye for detail

If someone has cold virus it is considered good etiquette to wear a particulate filter mask to avoid infecting other people

I found owners manuals for Fronteras and Lobitos but no Sherpa Ts. If you want a scan of one of them let me know. I suspect the diagram for the last model Lobito will be the same as for the M158.

Andrew I think the rules for Australian Trials have moved away from having to plug the bar ends. I think we have moved to line up with the rest of the world and the requirement is that the ends of the bars are either plugged or covered by the grips - so if the end is ripped off the grip, it will not pass scrutineering without the end of the bars being plugged. As for the sizing issue, bars come in different internal diameter and so do bar end plugs. As the previous writer pointed out, it can reduce the risk of throttle tube damage if that side has a bar end plug that protects the throttle tube. Another complication to this issue is that there are also bar end masses made to change the natural resonant frequency of the handlebars (for road bikes). These look a lot like bar plugs and these are sometimes sold alongside the types of bar ends that are made to protect the grip/tube on our dirt bikes. I use a home made plastic internal plug on the left end (very light) and either a home-made internal plastic plug, or a protective aluminium end cap on the throttle end. Some throttle tubes require a hole drilled through the end to fit the plug through. Yes you have to cut a hole in the end of the grip if you use external protective caps

Hi Justdrew - and welcome to another Aussie. I used to live at Mt Elliot (Alligator Creek) and ride Trials, go trail riding and race Pony Express in and around Townsville 1988 to 1995 and love the area. I might have a wiring diagram for a Sherpa T in the shed. I'll have a look tomorrow Regards David

I love being able to choose which time period of postings I want to see.

have a look at the JT sprockets website. You can compare the dimensions for sprockets of a huge range of bikes

There is no more torque on the bottom clamps with this arrangement than there would be if higher rise handlebars were fitted to the original mounts.

I am in the process of getting my 348 working well and would like some advice about the issue with the plastic bushings in my forks. After reading Martin's posting I wondered of the problem I am having with my 348 forks might be caused by that same issue. My problem is that when the forks bottom they feel quite harsh in comparison with when the forks bottom on my OSSA MAR and Bultaco M49. The action of the 348 forks is otherwise fine. Tonight I tested the action of one 348 fork leg without the spring in it and it did stick a bit at the bottom end of the travel. I pulled that leg apart and the plastic sleeve seemed to be a neat fit in its mating part. I measured the clearance between the parallel sections of the parts at between 0.1mm and 0.2mm and the plastic sleeve is also slightly belled out on the bottom end. I then measured similar parts from a set of Bultaco Betor forks and the clearance between those parts was 0.5mm. I believe the function of these parts is to provide a hydraulic anti-bottoming function that is effectively very heavy compression damping that happens in the last 25mm or so of the fork stroke. Am I right in assuming that the clearance between the Montesa sleeve and mating part should be more like the 0.5mm that I found with the Bultaco forks? Note the Bultaco parts do not appear worn or damaged in any way and are both made from aluminium. The Montesa plastic sleeve mating part is made from steel.

Another thing is the type of riding style you have. If you generally ride gently and want to maximise traction and control, go for the softest springs you can. If this is you, then aim for about 50% of the travel used (front and back) when you do the Glenn test. Some other people like jumping off big things. They are usually willing to compromise a bit of traction and control for the sake of not breaking wheel hubs and spokes, and so they opt for springs on the stiff side to avoid harsh bottoming. If you are like that, then aim for 30% to 40% of the travel used up when you do the Glenn test.

Further to what Glenn said, if when you do what he has said, you end up with the preload set so high that the shocks are topped out with no rider aboard, that is telling you that the springs are not stiff enough. Betors come with 40 or 50 pound per inch springs. If your bike is a standard TY175, then I would suggest as a guide that if the rider is over 90kg to use 50 pound springs and under 90kg to use 40 pound springs. If your TY175 shockie mount locations or footpeg locations have been customised, then that spring rate recommendation may not apply. For bashplate's TLR, the rear suspension leverage ratio and footpeg position is different to a TY175 so may need different springs for the same weight of rider.

I can take a photo of mine but it wont be until the weekend and no it is not for sale

Yes the brake pedal height, and fore/aft distance relative to the footpeg is very important in trials. Reaching either way is a disaster for your position on the bike. Anything is possible when it comes to modifying brake pedals. While you are at it (lowering the pegs) have a think about what you are going to do with the stand mount too. One option for OSSAs is to fit a wheel that has the brake and sprocket on the same side so you can do away with the cross-over rod and bowden cable which makes for a sub-optimal brake action on the standard MAR. That also opens up options for how you make the brake pedal fit in with lowered footpegs.

In support of this, US Dirt Bike magazine did a series of dyno runs with a two stroke MX bike and found that the more oil there was in the premix, the more power it made. They went all the way to a very high oil concentration (something like 15:1 fuel to oil) and the pattern remained

I just measured the dish in an original TY250 sprocket at 4.5mm, which is pretty close to 3/16".

fergie are you saying a 428 sprocket is 3/16" thick? or that the spacer should be 3/16" thick?

I'll have a guess the it means that the handlebar mounts are in front of the steering axis

Guy I can't say I'm any smarter than you but I do remember that the thickness you need for a sprocket spacer on a TY250 is the same thickness as the sprocket which from memory is 1/4" That is based on the offset of an original Yamaha dished sprocket. There are probably lots of TY250s out there with bent swingarms that may need a different thickness spacer. Regards David