TY250 E Piston

Need help finding information or parts for that old machine in your shed? Someone in here will know!

Moderator: Moderators

Guy53
A grade participant
A grade participant
Posts: 195
Joined: Tue Nov 09, 2010 4:22 am
Bike: Ty250A
Club: ATAQ

Re: TY250 E Piston

Postby Guy53 » Wed Mar 02, 2011 11:06 am

Here are the pictures of the pistons,
DT on the left and the Ty on the right. Note that the corner of the skirt on the ty piston is slightly cut to clear the crankshaft.

Guy
Attachments
IMG_2571.JPG
IMG_2570.JPG



TriCub
Expert participant
Expert participant
Posts: 273
Joined: Fri May 28, 2010 11:38 am
Bike: Triumph
Club: Wester districs trials club

Re: TY250 E Piston

Postby TriCub » Wed Mar 02, 2011 2:20 pm

Just picked up a Wossner catalouge this morning and they list the same piston for DT2/3, DT250, MX250 and TY250. I Guess they would have the corners cut away making them universial. If you got a DT piston it would be easy to trim of the corners to suit.
Incidently while I was at Serco I checked and they have the .5mm Wossners in stock.



Stanm
A grade participant
A grade participant
Posts: 121
Joined: Wed Jan 14, 2004 10:17 am

Re: TY250 E Piston

Postby Stanm » Wed Mar 02, 2011 9:50 pm

Hi Tricub & Guy
Thanks for the info I think I may be able to source a genuine TY/DT Piston. But still interested in the DT piston code.
I looked at MX250 pistons on Ebay the original pistons only have one ring and the skirt on quite a few look cut away more on the pin sides. So the aftermarket may suit but original???
Tricub thanks for the info on rebore I will try another rebore shop tomorrow. Its on the original bore so sould be OK square wise.

Cheers

Stan



Guy53
A grade participant
A grade participant
Posts: 195
Joined: Tue Nov 09, 2010 4:22 am
Bike: Ty250A
Club: ATAQ

Re: TY250 E Piston

Postby Guy53 » Thu Mar 03, 2011 2:21 am

Hey Stanm be carefull in choosing MX, YZ or other high reving motor pistons, they don't have the same shape ( high reving motor tend to heat up ) they will be loose and you won't like the sound of your motor , plus I prefer a 2 rings piston.

Guy



Stanm
A grade participant
A grade participant
Posts: 121
Joined: Wed Jan 14, 2004 10:17 am

Re: TY250 E Piston

Postby Stanm » Sat Mar 05, 2011 6:30 pm

Thanks guys for your comments. I got a original 0.25mm oversized piston from ebay and Phil at Dandenong Motorcycles said no problems to bore to that.

So some info on the A vs E model as promised. I am keen to know why they are so different in power

I have started with the piston and head

Pistons look the same and measure the same or close with measurements by vernia
I have an original E piston that weighed 288 gms and a 1.0 0/S A the weighed 311gm. So that about same for weight vs size.
I think the E and the A piston are the same

The Heads
I levelled the heads and added water and got the following

Both heads take 33ml . I measured to the plug and 1cm in and measurements close to the same so I think the same profile. I believe the E and the A head are the same.

If anyone can suggest a critical dimension i should check please advise.

I will investigate the Cylinder next and Post the results

Cheers

Stan



David Lahey
Champion
Champion
Posts: 4062
Joined: Thu Jun 05, 2003 7:01 pm
Bike: Many Twinshocks
Club: CQTC Inc, RTC Inc
Location: Gladstone, Queensland

Re: TY250 E Piston

Postby David Lahey » Sat Mar 05, 2011 7:26 pm

Stan please compare the distance from the top of the exhaust port to the top of the cylinder. I'm thinking the E distance might be greater than the A.
Please also have a look and see if the conrods look different. I remember reading that one of the improvements that came with the B model was a lighter conrod compared with the A. I think this might be right too because my B and D motors have much less motor frequency vibration than the A.


relax, nothing is under control

Stanm
A grade participant
A grade participant
Posts: 121
Joined: Wed Jan 14, 2004 10:17 am

Re: TY250 E Piston

Postby Stanm » Mon Mar 07, 2011 9:21 pm

Hi David
I measured up most dimensions on the A & E cylinder and taped off the transfer ports and measured their volume by filling with water. I have attached the scribble results. From results conclusion is from the outside they look different but inside they are quite similar. Will investigate the crank and crank case volume next.

Cheers

Stan
Attachments
StanMSCAN01.jpg



Stanm
A grade participant
A grade participant
Posts: 121
Joined: Wed Jan 14, 2004 10:17 am

Re: TY250 E Piston

Postby Stanm » Mon Mar 21, 2011 10:29 pm

Hi David
Finally got around to checkingthe bottom end of the A vs E

I have both with the cylinder off at the moment.

Filled both cranks with petrol and got close to 490ml in both so not a great difference there.
Crank wieghts on E may be very slight ly thicker but only by 1mm.

Con rod on the A has markin of '311" and is 8mm thick

Con rod on the E has "498" marking and is 6.5mm thick

I got an original piston from Ebay and I believe it is a DT piston. It is almost 30gms heavier than the original Piston.

I will let you know how it goes.

Cheers
Stan



David Lahey
Champion
Champion
Posts: 4062
Joined: Thu Jun 05, 2003 7:01 pm
Bike: Many Twinshocks
Club: CQTC Inc, RTC Inc
Location: Gladstone, Queensland

Re: TY250 E Piston

Postby David Lahey » Mon Mar 21, 2011 10:50 pm

Stan I'm amazed that the port timing was so close between your TY250A and TY250E cylinders. I'm wondering if your A model is of a later type to mine. My A model has a very low ID number so I think it is an early one.

The first photo shows the front of the cylinder on my TY250A. Does your A cylinder have the flat round bit above the exhaust pipe like this one, or does it look like the cylinder in the second photo (which I think is an early B model cylinder) with the fins going all the way across the front?
David
Attachments
P9140029.JPG
P9140033.JPG


relax, nothing is under control

Guy53
A grade participant
A grade participant
Posts: 195
Joined: Tue Nov 09, 2010 4:22 am
Bike: Ty250A
Club: ATAQ

Re: TY250 E Piston

Postby Guy53 » Tue Mar 22, 2011 11:45 am

David, I have 2 434 cylinder and none of them as that flat round above the exhaust.

Guy




Return to “Twinshock & Classic Trials”

Who is online

Users browsing this forum: No registered users and 37 guests