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Messages - David Lahey

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General Discussion / Re: Plastic Guard suppliers
« on: January 21, 2019, 08:38:10 PM »
I've been buying the Preston Petty stuff from the US (Paul Stannard)

General Discussion / Re: The Shit They Sell on Ebay
« on: January 10, 2019, 10:54:09 PM »
perch and lever look like original gear from TY175/TY250

Yamaha / Re: Yamaha DT1, I have found a whole new interest & respect
« on: January 01, 2019, 11:08:12 AM »
I bought a DT2 in 1977. It was in original condition and had no problems mechanically and looked like it had only been used on the road. I had wanted a bike to ride to work to avoid putting too many kms on my IT175 and for that purpose was a good choice. I did a cosmetic resto on the DT2 and remember being able to walk into my local Yamaha shop and buy a complete new seat for it. I rode it to work for a while and even did some sort of all-day nav run on it (12 hour road trial?) but didn't fall in love with it. The main issue for me was the scary-poor handling in the dirt which in hindsight would have been greatly improved with a 21" front rim and decent tyres. As well as the standard Yamaha exhaust, it came with a Bassani exhaust and a bigger carby? (Sleepy may remember). The pipe gave it more top end power (and noise) but with the standard (fairly high) gearing it was hard to keep it in the fat part of the rev range even on the road.
Sleepy's RT3 (mentioned in a previous post) had been very well developed in the power and handling department at the time and was a far more enjoyable bike to ride than my standard DT2.

Tech Talk / Re: Are there any good mods for Yam DT2 forks?
« on: December 27, 2018, 11:49:48 PM »
Cartridge emulators are available. I run Race Tech gold valves in a set of TY250 forks which like the DT2, have 34mm Kayaba fork tubes. The gold valves took ages to get set up but are quite good now.
On another trials bike with TY250 forks I have fitted aftermarket (modern) damper rods made in the UK which worked great without any setting up required. They are made of aluminium, have slightly more travel than standard (about 5mm extra) and most importantly have much better damping action than the standard damper rods provide.
I'm sure either of those methods would also make DT2 forks work better for MX.

Tech Talk / Re: Yamaha shift stopper lever trouble
« on: October 08, 2018, 08:11:27 PM »
A picture is worth a thousand words

Suzuki / Re: DR500Z Swingarm
« on: September 22, 2018, 09:50:44 AM »
When you do your build, It's a good idea to retain the cush drive hub to prolong the life of the gearbox

Tech Talk / Re: Curing handlebar vibration.
« on: September 19, 2018, 09:52:27 PM »
One of my bikes (with un-braced solid alloy bars) is so bad I lose vision frequently enough that it is a problem. I'm thinking of using lighter bars to get away from that frequency, or fitting a brace. The front wheel/forks resonate at idle too but that doesn't affect my eyeballs

General Discussion / Re: Sciatic nerve
« on: August 09, 2018, 08:35:41 PM »
Wow I just looked and Charles is still in business after all these years

General Discussion / Re: Sciatic nerve
« on: August 09, 2018, 08:32:53 PM »
Yes, when I was in my 30s. It was terrible all right. I used to go to a therapist called Charles Angles or Angels at Alexandra Hills in Brissy who used to push it back into its groove which was fairly painful at the time but did work for a while each time. I eventually stopped having sciatic nerve problems.

Tech Talk / Re: Alluminium disc rotors, your thoughts?
« on: July 08, 2018, 08:26:59 PM »
As for weight saving compared with steel, aluminium (at room temperature) is approx 1/3 of the strength of steel and approximately 1/3 of the density of steel so there would be no weight saving

Tech Talk / Re: Alluminium disc rotors, your thoughts?
« on: July 08, 2018, 08:24:21 PM »
The strength vs temperature relationship for aluminium and its alloys is such that it would be useless for motorbike brake discs

Is Tony Ceglinski still about?? Never met a more passionate and enthusiastic motorcyclist!
Tony passed away a few years ago

Twinshock Trials / Re: Longterm TY250C
« on: June 18, 2018, 01:02:07 PM »
Yes that gear shifting description is fairly standard for those motors. You wouldn't want to be in a race.
The reason I asked about the flywheel band is that many years ago I took the band off one and liked it for a while then went to using a flywheel with a lightened band. I removed a bit at a time from the width of the band and ended up with about 2/3 of the band left. Since then I have lent the flywheel with no band to people who are trying to decide what to do with theirs. In each case they have ended up using a lightened band. That's why I'm interested in what you find and do with yours.
Yours being a C model would have come with a "heavy" band, same as B, D and E models. The A model came with a lighter band which is pretty much the same weight band as what mine ended up with.
As for your jetting, it may be worth trying a bigger main jet before trying to find an alternative needle or reshaping the needle, because the OEM Yamaha Mikuni is an odd design and alternative parts are not available from Mikuni parts suppliers. The slide and needle are shorter than a standard VM26 and were made that way to minimise the height and weight of the carby. The B model TY250 carby does have a different needle shape and main jet size to the CDE models and I suspect that they needed to change the jetting when they changed the design of the airbox.
Yes the Majesty damper rods are a good thing

Twinshock Trials / Re: Longterm TY250C
« on: June 18, 2018, 09:49:39 AM »
Lovely bike. I'm interested in what you think about the motor performance with the weight band removed

Sounds excellent  8)

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