TY 250 Improvements

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Stanm
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Some More Questions

Postby Stanm » Wed Jul 04, 2007 5:21 pm

So does anyone know how the pros used to set uo the TY250's. For example mine has a flywheel weight ring which I believe is not standard but was a mod that was quite common.
I just use normal Unleaded. Does premium fuel make much of a difference.
Mine is set to standard timing, Can this be improved?
What are the best performing brake pads?
What about the aftermarket BJRacing fork springs? Anyone got these to comment on?
I put 520 chain and sprockets on but did not put on a spacer to compensate for the original dished rear. Had some trouble with the chain coming off. Can anyone tell me what the offset spacer thickness should be.

thanks
Stan



David Lahey
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Re: Some More Questions

Postby David Lahey » Wed Jul 04, 2007 6:10 pm

Stanm wrote:So does anyone know how the pros used to set uo the TY250's. For example mine has a flywheel weight ring which I believe is not standard but was a mod that was quite common.
Standard TY flywheels have a weight ring. The A model has a narrow ring and the B,C,D models have a wider ring. If you want a photo I will send one. I prefer riding competition with the ring removed for dry events and with the ring on for mud.

I just use normal Unleaded. Does premium fuel make much of a difference.
If your bike runs well, why change? Premium may make the bike run a bit smoother if you are having problems due to poor jetting or carbon buildup.

Mine is set to standard timing, Can this be improved?
Timing is adjustable to suit what you want. Standard timing works fine. Advance it a bit for more top end or * it a bit from standard for better throttle response at very low RPM. A hint here is if you set the timing using a static method, make sure you set the plug gap to recommended gap as a wide gap will affect the timing.

What are the best performing brake pads?
Ones that fit the shape of the drum properly. EBC pads have metal particles in the material which provide a stronger braking effect for the same cable pull than Yamaha TY shoes.

What about the aftermarket BJRacing fork springs? Anyone got these to comment on?
I bought two sets of B&J fork springs and rode with them for a couple of years in my TY250B and in my TY175 with TY250 forks and eventually took them out again as the spring rate was a bit high for my weight. They are well made and are high quality. If you are heavy and love big obstacles or trail riding, they are great.

I put 520 chain and sprockets on but did not put on a spacer to compensate for the original dished rear. Had some trouble with the chain coming off. Can anyone tell me what the offset spacer thickness should be.

6mm offset.

David Lahey

thanks
Stan



Stanm
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Postby Stanm » Thu Jul 05, 2007 6:16 pm

David
That's really good info and gives me a few things to tinker with and the excuse to test ride each weekend.
Yeh i saw a the TY 250 B has a flywheel weight that is much thicker. My A has nuts that stick out that are handy to hold with a screwdriver to take off the flywheel Nut. Do you have a special set up to take the weight off easily??
I hover between 85 to 90kg so I will take the BJ springs off my wish list. I used to hit the big obsticles but found I was chewing up tyres and injuring myself. So now cut back on this and concentrating on the slower technical stuff.
Is there another way to set the timing other than static? Can you use a Strob timing light? I have always just use a bit if chip packet foil to sense the points opening. I will check the spark plug gap.
Easy i will wip up a spacer from a bit of 6mm alum.

Thanks



David Lahey
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Postby David Lahey » Thu Jul 05, 2007 7:43 pm

Stanm wrote:David
That's really good info and gives me a few things to tinker with and the excuse to test ride each weekend.
Yeh i saw a the TY 250 B has a flywheel weight that is much thicker. My A has nuts that stick out that are handy to hold with a screwdriver to take off the flywheel Nut. Do you have a special set up to take the weight off easily??
I use two different flywheels. One with band and one without. I've heard that the ring can be taken off without cutting it but each time I have tried to get a ring off in one piece there has been some pretty fierce glue holding it on as well as the screws so I have given up and made a cut with a hacksaw to get it off without risking damage to the flywheel.

I hover between 85 to 90kg so I will take the BJ springs off my wish list. I used to hit the big obsticles but found I was chewing up tyres and injuring myself. So now cut back on this and concentrating on the slower technical stuff.
Is there another way to set the timing other than static? Can you use a Strob timing light? I have always just use a bit if chip packet foil to sense the points opening.
Yes set the timing close to the right spot static then check the timing with a strobe light. The strobe sensor is triggered by the HT lead and a 12V lawnmower battery powers it. My favourite timing is 22mm BTDC measured around the circumference of the flywheel rim.

I will check the spark plug gap.

Easy i will wip up a spacer from a bit of 6mm alum.
You will probably need to use countersunk head screws or machine the heads of the standard screws thinner to give clearance to the swingarm once you space the sprocket over to the left.

David

Thanks



Stanm
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Postby Stanm » Sat Jul 07, 2007 7:03 pm

David
I will give the dynamic timing a go tomorrow. I previously made some timing marks in the flywheel and case and standard timing looks about another 6mm BTDC than your 22mm. My points gap is on the low side. Points seem OK so I believe it must be a worn cam to have this effect?
It will be interesting to see where the timing really is compared to wher i think i set it. And to play wit the settings.
Have you Lowered you pegs? I made up some adapters and have the pegs in the lower cross tube. Also extended my pegs. Last trial I had some issues with clearance in tight rocks ( both of the things I did dont help) so want to optomise the size and position. Any ideas on this?
Cheers



David Lahey
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Postby David Lahey » Sun Jul 08, 2007 7:22 pm

Stanm wrote:David
I will give the dynamic timing a go tomorrow. I previously made some timing marks in the flywheel and case and standard timing looks about another 6mm BTDC than your 22mm. My points gap is on the low side. Points seem OK so I believe it must be a worn cam to have this effect?

More likely to be wear of the cam follower than wear of the cam.

It will be interesting to see where the timing really is compared to wher i think i set it. And to play wit the settings.
Have you Lowered you pegs? I made up some adapters and have the pegs in the lower cross tube. Also extended my pegs. Last trial I had some issues with clearance in tight rocks ( both of the things I did dont help) so want to optomise the size and position. Any ideas on this?

The pegs on my B model are only 25mm lower than standard and the handling is terrific and the bashplate still hits before the pegs. Let me know if you want a closeup photo.

As for how far the footpegs stick out sideways causing a problem with clearance to rocks, surely they can be made to reach to the outside edge of your boots before they become a limiting factor? If there is going to be a scrape against something, there is always the option to just lift your foot clear and allow the peg to be pivoted by the passing object.

David

Cheers



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smack
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Postby smack » Sun Jul 08, 2007 8:33 pm

Congrats on the win this weekend David, some nice riding on that TY of yours.



Stanm
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Postby Stanm » Mon Jul 09, 2007 9:55 am

David
Good to hear the TY had a win.
I used the strobe connedted to the car battery and found the timing to be about 25mm from TDC and altered it 22 mm. I did not notice the differenceto tell you the truth. Will stick with this for a while. But now will use the strobe to check the timing.
The cam follower is the bit on the points that touches the cam. This is still about 4 or 5mm long from memory so should be OK.
Yeh send me a picture of you peg set up please . Mine is almost at the bash plate. Bash plate hits first. Maybe I need to chamfer my pegs a bit more so they do pivot more easily when they hit.
The Front end is definetly better with the 20w.

regards



David Lahey
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Postby David Lahey » Mon Jul 09, 2007 11:27 am

TY250B footpeg photos

Click on photos for higher resolution

David
Attachments
TY250B pegs July 07 004.jpg
TY250B pegs July 07 003.jpg
TY250B pegs July 07 001.jpg



David Lahey
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Postby David Lahey » Mon Jul 09, 2007 2:45 pm

Thanks Smack. It was a good fun weekend all right. You looked very much at home on Cedric's TY175.
Are you going to boost the number of Hondas at next year's Brooweena with one of your TLs or stick with the winning formula and ride a two-stroke again?




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