Chippy asked and a couple of other guys may be interested in how I'm going with my s l o w TY rebuild.
It actually started off as 2 bikes bought as spare parts for my perfect patina twinshocker.
I've had the frame blasted and painted locally. Most of the alloy parts are being blasted at the moment. If I like the finish and the company is happy, I'll post their name with the photos when I get them home again.
I've put both heads on my lapping plate, had both barrels rebored and I painted with VHT and baked. Now, I may have used someone else's oven... Karma is a bitch though. As I forgot that the windows were closed. Cooking paint smells awesome haha.
The left side engine cases have both been damaged from the drive chain coming off and all the lovely remodeling that it does. I have had 1 welded and that's where the engine stalled.
I figured if I build a rolling frame, I'll have a reason to build the engine and so on.
Basket Cases
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Re: Basket Cases
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- Main frame sandblasted and painted
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- Champion
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- Bike: Many Twinshocks
- Club: CQTC Inc, RTC Inc
- Location: Gladstone, Queensland
Re: Basket Cases
Yes OSSA clutch springs are very stiff. They need to be because of the design of the clutch. The pressure plate force required in a motorbike clutch is determined by a few things including:
The diameter of the contact zone of the friction plates
The speed reduction of the primary drive
Motor performance
The number of friction plates
The contact patch width on the friction plates
The OSSA clutch is quite small in diameter for a 250, but a good thing about OSSA clutches is that the clamping force is easily adjustable. Because the spring retainers use nuts, you can set the spring preload at the point where you get just enough force to not slip. If you buy modern high-friction plates and have nice flat steel plates you can get a very nice action even with the standard length lever arm.
The diameter of the contact zone of the friction plates
The speed reduction of the primary drive
Motor performance
The number of friction plates
The contact patch width on the friction plates
The OSSA clutch is quite small in diameter for a 250, but a good thing about OSSA clutches is that the clamping force is easily adjustable. Because the spring retainers use nuts, you can set the spring preload at the point where you get just enough force to not slip. If you buy modern high-friction plates and have nice flat steel plates you can get a very nice action even with the standard length lever arm.
relax, nothing is under control
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Re: Basket Cases
I forgot to put this photo in my last post. The rechromed forks tubes look awesome. I miss the patina of the original as found condition, but these won't eat fork seals anymore. Work done by Rad hard chrome in Brisbane
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- Champion
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Re: Basket Cases
Looking good. It's great that you are retaining as much patina as practical.
I also like the neat way you protected the swingarm pivot internals and steering head internals for the blast and paint.
Seeing that big seat reminded me of a bike that one of the salesmen at Annand and Thompson Yamaha had set up for riding enduros. I think it was a YZ seat he had fitted to his TY175 and reckoned it was a great bike for the events we used to ride in the mountains.
At the same time, a faster, sponsored Yamaha rider (Geoff Petler?) was using what started out as a YZ125C.
I also like the neat way you protected the swingarm pivot internals and steering head internals for the blast and paint.
Seeing that big seat reminded me of a bike that one of the salesmen at Annand and Thompson Yamaha had set up for riding enduros. I think it was a YZ seat he had fitted to his TY175 and reckoned it was a great bike for the events we used to ride in the mountains.
At the same time, a faster, sponsored Yamaha rider (Geoff Petler?) was using what started out as a YZ125C.
relax, nothing is under control
Re: Basket Cases
chippy wrote:Hi Everyone,
Phil you are correct. The end of the shaft has been machined down where the spline was. Someone has been at it well before it came into my hands.
Your previous picture:
Chippy
Thanks for the info.
Do you think it is possible to find another shaft with the correct spline and weld it to my shaft (hopefully concentrically).
Any ideas on what other bikes have the same kick start spline as a Cota 123/172 ?
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Re: Basket Cases
David Lahey wrote:Looking good. It's great that you are retaining as much patina as practical.
I also like the neat way you protected the swingarm pivot internals and steering head internals for the blast and paint.
Actually David, I am not going to be keeping the aged patina on the refurbished bike. It's going to look like the other 10, 000 repainted TY175's in Australia. I'm not going to be doing any real mods to it either. Just a carby change and no oil pump.
I'm having a ball on my old barn find patina bike with everything as it left the factory. The long extra padding seat is great for riding between sections and I don't think it's a hindrance in sections.
I'll end up with the original bike I've had for a couple of years, 1 that looks nicely painted etc and the JC spares bike.... Until I decide to fix it up too haha
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Re: Basket Cases
In reply to Phil,
I would be very surprised if a kickstart shaft with the end welded on would last more than 2 kicks.
The weld would create a weak spot in the steel shaft due to the heat imparted by welding effecting the microstructure of the steel.
The steel they use for shafts isn't the garden variety and doesn't take kindly to welding.
Which leaves you with three options:
1. Have a shaft manufactured by a good machine shop.
2. Search for a replacement for sale.
3. Pretend that you haven't noticed the bend and twist in the shaft and see how long it hangs on for.
I would be very surprised if a kickstart shaft with the end welded on would last more than 2 kicks.
The weld would create a weak spot in the steel shaft due to the heat imparted by welding effecting the microstructure of the steel.
The steel they use for shafts isn't the garden variety and doesn't take kindly to welding.
Which leaves you with three options:
1. Have a shaft manufactured by a good machine shop.
2. Search for a replacement for sale.
3. Pretend that you haven't noticed the bend and twist in the shaft and see how long it hangs on for.
Re: Basket Cases
Hi Kurt
Yes, I realise the issues with a welded shaft.
I’m constantly using option 2, but will probably end up with option 3 unless my luck changes.
I did order a lot of parts from a Spanish supplier including a kick start shaft as they had it advertised on their web site. But they unfortunately couldn’t supply it for some reason
Phil
Yes, I realise the issues with a welded shaft.
I’m constantly using option 2, but will probably end up with option 3 unless my luck changes.
I did order a lot of parts from a Spanish supplier including a kick start shaft as they had it advertised on their web site. But they unfortunately couldn’t supply it for some reason
Phil
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- Champion
- Posts: 4062
- Joined: Thu Jun 05, 2003 7:01 pm
- Bike: Many Twinshocks
- Club: CQTC Inc, RTC Inc
- Location: Gladstone, Queensland
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- Champion
- Posts: 4062
- Joined: Thu Jun 05, 2003 7:01 pm
- Bike: Many Twinshocks
- Club: CQTC Inc, RTC Inc
- Location: Gladstone, Queensland
Re: TY250 swingarm bushes/bearings
David Lahey wrote:I will soon be replacing the bushes in a TY250 swingarm and decided to try out something a bit different this time.
The gear in the top of the photo are the normal bits used for this (Yamaha OEM parts and an aftermarket inner bush from John Cane in the UK).
The lower package is four needle rollers and two bronze thrust bearings from the US, supposedly for TY250. I'm keen to try them out but am wondering how easy the needle roller outers will be to get back out again when/if they fail. I think I'll need to be diligent with servicing it if/when I ride in water.
Has anyone tried this setup?
Well here we are a couple of years later and I noticed that the swingarm on the TY250 with this roller bearing swingarm pivot setup was starting to seize up.
The grease was still fresh but the surface of the inner bush had failed where one of the four sets of rollers ran and was starting to fail in two of the other locations. The rollers on the set that had been gouging away at the inner bush look fairly dodgy. The other three sets of rollers look OK.
I suspect that the inner bush would have given perfectly good service had I used the normal plastic bushes but using needle rollers may have caused too much stress on the surface of the bush.
relax, nothing is under control
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