TY 250 Improvements

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Stanm
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TY 250 Improvements

Postby Stanm » Mon Jun 25, 2007 8:47 pm

Hi
I have a TY250A that I am running in the Vic troy series. It goes OK
but I am no expert in the suspension set up or what can be done to improve them.

At present I have standard fork springs with 17mm preload 7.5w oil 175cc and the forks are down in the clamps 6mm. Rear end has steel falcon shocks 340mm long. Footpegs have been lowered. Flywheel is weighted.

One problem I need to fix is the baffle in the main pipe is rattling about. (bike still runs ok). Any one know wat side it is supposed to be fixed to?

I would appreciate any advice on how to improve the handling power delivery, weight reduction etc



Stu
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Postby Stu » Mon Jun 25, 2007 11:05 pm

Can't help you out on the muffler problem. It sounds like you have the suspension sorted though. I'd like some ideas on how to lighten my TY as well. I've had mine for 20 years and i ride it anywhere and everwhere!


Feet up, as always!

David Lahey
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Re: TY 250 Improvements

Postby David Lahey » Tue Jun 26, 2007 6:06 am

Stanm wrote:Hi
I have a TY250A that I am running in the Vic troy series. It goes OK
but I am no expert in the suspension set up or what can be done to improve them.

At present I have standard fork springs with 17mm preload 7.5w oil 175cc and the forks are down in the clamps 6mm. Rear end has steel falcon shocks 340mm long. Footpegs have been lowered. Flywheel is weighted.

One problem I need to fix is the baffle in the main pipe is rattling about. (bike still runs ok). Any one know wat side it is supposed to be fixed to?

I would appreciate any advice on how to improve the handling power delivery, weight reduction etc


The main exhaust section on a TY250A does not have a baffle but is a double wall design. The inner wall is made of perforated steel and is spot welded to the outer wall. The noise may also be a mud-wasp nest or a lump of carbon.

Re your suspension: I've found that 15 or 20 WT oil works best for me (90kg) and I run standard springs and standard preload. Be careful adding extra preload to those springs as they will coil-bind, limiting travel. Setting oil level using depth measurement is more repeatable than measuring oil volume and those forks are sensitive to both over and underfilling. Too little oil - they snore and too much oil - travel is reduced. 125mm from the top with forks bottomed works well.

Rear I use 50lb/inch springs on 340mm Falcons with 10wt oil. Preload set to give 5mm sag unladen.



Stanm
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Re: TY 250 Improvements

Postby Stanm » Tue Jun 26, 2007 9:19 pm

David Lahey wrote:
Stanm wrote:Hi
I have a TY250A that I am running in the Vic troy series. It goes OK
but I am no expert in the suspension set up or what can be done to improve them.

At present I have standard fork springs with 17mm preload 7.5w oil 175cc and the forks are down in the clamps 6mm. Rear end has steel falcon shocks 340mm long. Footpegs have been lowered. Flywheel is weighted.

One problem I need to fix is the baffle in the main pipe is rattling about. (bike still runs ok). Any one know wat side it is supposed to be fixed to?

I would appreciate any advice on how to improve the handling power delivery, weight reduction etc


The main exhaust section on a TY250A does not have a baffle but is a double wall design. The inner wall is made of perforated steel and is spot welded to the outer wall. The noise may also be a mud-wasp nest or a lump of carbon.

Re your suspension: I've found that 15 or 20 WT oil works best for me (90kg) and I run standard springs and standard preload. Be careful adding extra preload to those springs as they will coil-bind, limiting travel. Setting oil level using depth measurement is more repeatable than measuring oil volume and those forks are sensitive to both over and underfilling. Too little oil - they snore and too much oil - travel is reduced. 125mm from the top with forks bottomed works well.

Rear I use 50lb/inch springs on 340mm Falcons with 10wt oil. Preload set to give 5mm sag unladen.


Guys
thanks for the feedback
Re the muffler the inner perforated wall must have come loose as I cut a hole in the muffler and you can see it moving about. I rivited a patch over the hole as i was not sure of what best to do.
So can I get any lightweight /performance replacement or is it best to stick wit the original?
My 175cc of fork oil( Lazy way to do it I know) is about 150mm oil level so i have less oil than you. So i will try some 20 W and higher level.


Stu
I have been listing some of my ideas for weight reduction but not sure whether the effort is justified except for item 6

1/ Drilling the rear sprocket
2/ Alloy side stand or remove it
3/ Alloy tank
4/ Lighter Seat ( Mine is already Fiberglass)
5/ Cut off Misc small brackets
6/ Rider to loose weight

Anyone know if boysen reed are available and worth considering?

Thanks



David Lahey
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Postby David Lahey » Tue Jun 26, 2007 9:55 pm

Generally the higher the item is on the bike and the closer to the front or back the more benefit it is to lose a given amount of weight. Same for the front end, weight lost from the wheel rim or handlebar ends will have a bigger effect than the same weight lost from the wheel hub.
In other words the weight of the bashplate or footpegs or motor flywheel is much less important than the fuel tank or exhaust.
Yes Boyesen reeds available for TY250 from B&J racing. I have some on order - yet to try.
Yes better (fully aluminium main section and end muffler) exhausts are available. Still uses steel header section. Brand is WES. Quite expensive but works well and much lighter than stock. B&J Racing sell WES as do many other places.
You can make a thin-wall stainless steel header section and save weight.
Yes remove the stand.
The standard TY250B,C,D aluminium tank is pretty light and fits TY250A.
Majesty replica aluminium tanks are even lighter at 1250grams but are very expensive.
The steering head stem can be replaced with an aluminium alloy item at great expense as can the bolt that screws into the top of the stem.
I'm assuming you have lightweight handlebars already.
Aluminium rear sprocket drilled to the max.
The aluminium bodied Falcons save weight.
Rider losing weight doesn't help the bikes handling. It is the bike that is improved by losing weight.
Suppliers:
B&J Racing (Tennessee) http://www.bjracing.com
Moto Majesty (UK) http://www.yamaha-majesty.com
France Trial Classic (France) http://www.francetrialclassic.com/fr
Trials and Trails (UK) http://www.tytrials.com



Stu
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Postby Stu » Thu Jun 28, 2007 1:41 pm

At this stage getting the rider's weight down would be the easiest to do! We'll see at mt Kembla this weekend.


Feet up, as always!

Stanm
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Postby Stanm » Thu Jun 28, 2007 10:02 pm

David
Thanks for the comments on the weight reduction. I figure every bit counts and it will either cost time, effort and or money. So I will chip away at it.

Do you have A WES exhaust? I am interested to know what the boyesen reed perform like.


Thanks for the web sites.Some great stuff on them.

Here is one I used that has a good article on setting up suspension

http://www.gasgas.com/Pages/Technical/t ... -tips.html.



David Lahey
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Postby David Lahey » Fri Jun 29, 2007 7:19 pm

Yes Stan. I chip away at my bikes too. That's why it has taken me 12 years from getting the first TY250 till I have finally bought my first set of Boyesen reeds for one.

Getting the suspension right, motor running perfectly, new tyres, strong brakes, nice controls and the bike running as reliably as possible are my primary goals.

Those things are more important to me than the weight savings from a WES exhaust so that mod hasn't happened yet but is definitely on the list.



Stanm
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Postby Stanm » Mon Jul 02, 2007 6:29 pm

David
I tried the 20W weight @175cc in the forks and it did no get so twitchy in rocky sections so I will stick with it for a while.
I also burnt out my exhaust on the weekend. Basically built a fire and threw the exhaust on and rotated ot now and then. Waiting till it stopped smoking and then steam cleaned it when it cooled down.I took off the patches made to look in the exhaust and steam cleaned through these which made it easier to rid of the gunk, I recon it weighed at least half a kilo lighter. Didn't seem to improve the performance but it is a bit quieter.
Somene told me that they soak the exhaut with petrol before burning. So what is the normal method of cleaning a two stroke exhaust?

Cheers



David Lahey
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Postby David Lahey » Mon Jul 02, 2007 7:03 pm

Good to hear the front suspension is working better.
If the exhaust is steel only ie no mineral fibre sound deadening sections, it can be burned out. What you did on the fire is pretty normal. Oxy acetylene welding gear works a treat and usually doesn't need any follow up cleaning.
If there was still gooey gunk inside after the burnout, you didn't burn it out for long enough. Do run the bike soon after the cleanout to prevent the pipe rusting on the inside.
Mineral fibre melts and makes a mess if you try and burn a pipe that has it inside (like a Sherpa T front muffler)
If you live in a city there may be anti-pollution laws that prevent you cleaning it out this way.
I've heard that motorbike shops have a special solvent for cleaning out the gunk without burning, which may be needed for bikes with aluminium exhausts or steel exhausts with special coatings which would otherwise be destroyed by the high temperature generated when burning out.
One time when I cleaned out a well-used TY175 pipe, it was about 650grams lighter than before and the bike ran better too (cheap weight loss hey?)
I wouldn't think it was very safe to soak the exhaust in petrol due to the risk of it exploding the pipe when lit up. I've never needed to add anything to get it to burn all the way through.




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