Basket Cases

[paulo]

Just worked out - swingarm is from a Honda TL250

I should have got that one! Greg mentioned TL250 swingarms when we swapped chain tensioners a while back. The one i sent him is on the bike.

I've done the same footpeg mods as Greg, i was wondering whether either David or Greg feel that a slight drop in height would be an improvement? I'm new to trials but feel like I might be positioned too high on the bike?

On the front brake question, i did a bit of work on mine on the weekend and have decided the problem is the substandard aftermarket brake cable. I've ordered a Venhill cable which I've had success with in the past so hopefully it helps.

[David Lahey]

Footpeg height on any bike is a personal thing. The main influences on what is the right footpeg height for you are how tall you are and the handlebar rise.
There are pros and cons for footpeg height too. The lower they are, the easier it is to balance the bike stationary. The negatives are that the lower the pegs are;
The less room your bum has when unweighting the rear end of the bike when doing things like crossing a big log, or jumping up onto a rock. If you have long legs this won't be a problem if you lower the pegs a bit.
The lower the pegs, the more things hit your boots. Turning a twinshock properly requires leaning it over and even with pegs in the standard position on an RL, you will probably have a boot/object conflict now and then.

One way to make it more comfortable is to fit higher rise bars, or bar risers. If you look at photos of bikes like the RL being ridden in the 1970s, you will see they had handlebars with a much higher rise than what is commonly available nowadays. I tried lowering the pegs on a TY250B, and while the balance stability felt great, I kept hitting my bum on the rear frame loop, and the bike seemed to get in the way more when riding technical stuff.

On a few of my bikes I have fitted handlebars custom made to replicate the high rise handlebars that the bikes came with in the 1970s, and I think those bikes are comfortable and have good handling with their standard footpeg height (KT250, 1968 Sherpa T, OSSA MAR, Montesa 348). I'm 176cm tall.
Modern bikes have a higher steering head relative to their footpeg height so they work best with lower rise bars than 1970s bikes. That is why modern bars are a bit too low for average height riders on old bikes.
I can't remember what bars are on your RL but if they are standard modern trials bars, they will probably be too low if the pegs are in the standard location

[David Lahey]

I fitted the re-machined TY250D clutch basket today and the clutch now releases beautifully, and takes up beautifully. All I did was change the basket. All the clutch plates went back in in the same order they came out and I didn't do anything to any of the plates, springs or the pressure plate.
Thank you, MST Engineering
I will try it again in a few days to see how well the clutch releases from cold after the bike has sat unused.
An interesting thing I learned today when looking up the torque for the clutch nut in the Yamaha service book, was the reason for the weird shape of the driven (steel) clutch plates, is that it is designed to reduce clutch plate rattle. The missing part of the OD of each plate causes each plate to be unbalanced, which means the plate is forced against the splines of the clutch hub when the clutch is disengaged with the bike moving. My finger is pointing to the lightened part of the plate

Ok I've now put four practice sessions on the bike since fitting the clutch basket with the machined fingers and the clutch is great. It releases instantly, there is so little drag you can easily shift into neutral with the motor running and bike stopped. When you put it into gear after starting it from cold, there is no lurch or crunch or unintended departure

[paulo]

Thanks David. I don't know what bars are on the RL, i pinched them off a mate who took them of his ty175. They're some sort of vintage solid bar, they seem fairly tall. Maybe it's just a matter of getting used to the bike.

[David Lahey]

Yes those bars look like they would be OK for height for people up about 6 feet with standard peg location. One thing though with trials bikes is the fore/aft position of the bars makes a huge difference to how the steering feels.
To find the right position for you, it's useful to have one practice section and try a few different positions for the bars to see what suits you. It needs to have a bit of up and down with turns combined.
Have a look at training videos too so you develop the right technique for tight turns (rear brake, footpeg weighting, body position) best one I've seen for learning to ride twinshocks well is the Mick Andrews training video made a couple of years ago, produced by the bloke who bought Sammy Miller Products

[Kombivan]

Nice.

[JC1]

Greg, I was just being facetious about the overall top gear ratio. For what its worth it works out at 13.3 (primary ratio x 5th gear ratio X final ratio) so it's not far off 15.

How much longer is the TL swingarm than the RL's?

[Greg Harding]

Hi Everyone,

Just worked out - swingarm is from a Honda TL250

Still trying to work out the bananas. Maybe where Greg lives is 15 degrees south of the equator? But hang on those must be Queensland bananas because they have a bend. Maybe the bananas have a 15 degree bend?

Maybe the first swingarm Greg tried with a moved-forward lower shockie mount bent like a banana?

David, yes, mmmm and no, but there were a couple of reasons for choosing TL 250 swingarm. Firstly, styling wise a RL swingarm has nothing in common with the frame other than it bolts on, there are round holes everywhere else on the bike, but not on the Swingarm! . Secondly the RL swingarm has kink bends which matches nothing else, whereas TL swingarm has radius bends more like a Banana!

Thanks David. I don't know what bars are on the RL, i pinched them off a mate who took them of his ty175. They're some sort of vintage solid bar, they seem fairly tall. Maybe it's just a matter of getting used to the bike.

Paulo, those bars look slightly higher than the ones on all of my RLs which seem fine for my 1800 mm height.

Greg, I was just being facetious about the overall top gear ratio. For what its worth it works out at 13.3 (primary ratio x 5th gear ratio X final ratio) so it's not far off 15.

How much longer is the TL swingarm than the RL's?

John, TL swingarm is 2 inches longer overall.

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[JC1]

Continuing the theme of spotting mods to the RL

So many more subtle changes to be seen:

Brake pedal & outer cable stop moved back (15mm?)

Front engine mount plates diff

Front downtube appears slightly closer to cylinder & closer to bottom front engine mount

Exhaust midsection is different, perhaps shorter (by 15mm?)

Diff header pipe - also looks shorter. Maybe to clear front wheel on compression of forks on account of other mods.

Bottom rear engine mounts look more upright - hard to tell in the pics & I maybe imagining it, but perhaps to move engine back.

Rear top engine mount looks now to be under the cut-out downtube rather than in front of it (as on std RL)

Tank looks closer to steering head & front of tank is trimmed. I don't think tank has been moved forward, I think the front end has been moved back.

So it seems to me that, apart from the s'arm pivot being moved forward, the engine is moved back a little (15mm??) & the engine cradle & backbone have also been shortened keeping the same rake.

ie the front end is effectively back closer to the rest of the bike & with the longer swingarm the weight distribution is much better with more weight on front wheel. Overall wheelbase is perhaps slightly shorter.

Tho I could be imagining a couple of the small changes (as we've only got these few pics to go on), the whole thing looks so much more in proportion than a std RL (or even a Beamish). It no longer has that 'stretched neck' look.

The more I've looked the more I see how much thought has gone into it. Best modified RL I've ever seen I think. It looked superb in real life.

[Greg Harding]

Hi Everyone,

Adding BLUE text to respond to John.

Continuing the theme of spotting mods to the RL

So many more subtle changes to be seen:
!
Brake pedal & outer cable stop moved back (15mm?) Right again John.

Front engine mount plates diff Yes see photo at bottom? The standard plates have triangular holes which match nothing else on the bike and are generic left and right even though they don't fit either side particularly well!

Front downtube appears slightly closer to cylinder & closer to bottom front engine mount Yes 15 mm

Exhaust midsection is different, perhaps shorter (by 15mm?) WARM

Diff header pipe - also looks shorter. Maybe to clear front wheel on compression of forks on account of other mods. You are good at this, photo shows why header was Changed!

Bottom rear engine mounts look more upright - hard to tell in the pics & I maybe imagining it, but perhaps to move engine back. I actually thought the motor went forward, but I have been known to do things backwards, this build thread for example!

Rear top engine mount looks now to be under the cut-out downtube rather than in front of it (as on std RL) Those sleepless nights are paying off! I did not like the look of bulky rear engine mount. Downtube continues to base of frame.

Tank looks closer to steering head & front of tank is trimmed. I don't think tank has been moved forward, I think the front end has been moved back. The tank is the one I separated to remove dints on page 64, the flange was cut off all the way round.

So it seems to me that, apart from the s'arm pivot being moved forward, the engine is moved back a little (15mm??) & the engine cradle & backbone have also been shortened keeping the same rake. Yes and the rake is the same as I think got it right!

ie the front end is effectively back closer to the rest of the bike & with the longer swingarm the weight distribution is much better with more weight on front wheel. Overall wheelbase is perhaps slightly shorter. Wheelbase is 10 mm shorter than standard.

Tho I could be imagining a couple of the small changes (as we've only got these few pics to go on), the whole thing looks so much more in proportion than a std RL (or even a Beamish). It no longer has that 'stretched neck' look. Not having actually seen a BEAMISH in real life means there was no influence except I had previously swapped standard RL side covers for the YELLOW BEAMISH ones.

The more I've looked the more I see how much thought has gone into it. Best modified RL I've ever seen I think. It looked superb in real life.

Thanks John

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