ty 250 mono aftermarket parts

Got a technical question? Ask it in here.

Moderator: Moderators

Ferretflasher
A grade participant
A grade participant
Posts: 102
Joined: Fri Nov 24, 2006 7:45 am
Location: grimethorpe, UK

Re: ty 250 mono aftermarket parts

Postby Ferretflasher » Sun Apr 29, 2012 3:28 pm

Back in Blighty once more before flying back next month .... ! Darwin has the terrain I now see after a drive down to Adelaide River but in reality NT, Australia is for big dirt bikes and quads!! Its just too bloomin big and hot to do much else. Besides which, your rivers and creeks have Croc's in 'em, not normally a problem here in Barnsley, Yorkshire or top of Glen Nevis or Fersit !!!



sharpie
Junior participant
Junior participant
Posts: 19
Joined: Thu Jan 15, 2009 5:37 pm
Bike: 2011 Sherco 250
Club: Oakleigh & SQTA

Re: ty 250 mono aftermarket parts

Postby sharpie » Sun Apr 29, 2012 5:53 pm

Hi Ferret Flasher,
I spent the first twenty odd years of my life in Barnsley and the last twenty between NSW and Queensland the odd croc is much less of a risk than a night out in town. You do get used to the heat but having been a bricky over there breaking the ice on the water barrel to mix up on a winters morning is no fun either. If your back over here in a while take some holiday and see the country, come and have a ride with us in South East Queensland I'm sure we can find you a bike.

Sharpie.



Ferretflasher
A grade participant
A grade participant
Posts: 102
Joined: Fri Nov 24, 2006 7:45 am
Location: grimethorpe, UK

Re: ty 250 mono aftermarket parts

Postby Ferretflasher » Wed May 02, 2012 1:13 pm

Cheers Sharpie Mate!! You are right about nights out in town .... most folk are OK in Darwin but you do get the odd nutter and that mixture of lager & heat do make a dangerous cocktail. I find most Aussies laid back and very friendly, you can strike a good natter with anyone.... anyone at all! Mitchell Street was certainly a fab place on ANZAC day evening, all the US Marines were there and most of the Aussie Navy and Army in full uniform with full regalia & medals on show. Brilliant atmosphere, shall remember that for years !! The heat and humidity in wet season here were horrific to me but now cooling down as dry season takes over. Back to Darwin next week for another spell then home in July. Still like the old Barnsley though, winter in Thurgoland, Wortley or Wooley Edge still takes some beating!
The native locals however .... I find should be generally avoided at all costs, never yet seen a male sober and usually laid out senseless in a shop door way in a pool of their own vomit !
Next year may possibly working in Perth, depends on energy oil&gas business!
Cheers matey ..... shall start again soon on short-stroke TY mono when I catch breath.



Ferretflasher
A grade participant
A grade participant
Posts: 102
Joined: Fri Nov 24, 2006 7:45 am
Location: grimethorpe, UK

Re: ty 250 mono aftermarket parts

Postby Ferretflasher » Mon Jul 09, 2012 3:07 am

IMG_4441.jpg
Wiseco MX piston with large crescent cut-out to be assessed!!
IMG_4436.jpg
Barrel height about to be reduced by 2mm to accept short stroke crank


Hi reader .... back in Blighty once more ... and had chance to restart the short stoke saga!
Remember the point about pistons particularly 70mm types, well here is the Wiseco ex-MX variety that most Hamilton Yams are fitted with, note massive crescent cut out at back as opposed to the tiny windows in the skirt of standard. Birketts and Thorpe recommend these so good enough for me, its just that in say a Fantic, the lack of skirt soon causes wear due to the piston thrust and the dreaded rattle/slap soon onset! Anyway, if its OK by Thorpe & Co, then its OK by me. They do recommend that the bore is honed so piston "just" fits, any bigger and it will slap. So my piston is 70.50 and cold the skirt measure 70.39 so thats what I instructed machine shop to do!
Secondly, as its now a short-stroke, I have to loose 2 mm of barrel height because my crank stroke is now 66 and not 68 standard, so have just set up barrel in lathe to remove 2 mm off base. Third job for later is to set ignition timing so pick up coil is at around 5 oclock position rather than TDC but more of that later.

Spend 1 week in WA near Bunbury and Donnybrook/Balingup ... fabulous country, you Aussies have kept that little place a secret!! What fabulous trials country, hills, forests, rivers, rocks its got the lot!! You guys could run a 2-day trial out there just like the Reeth 2-day we have, country is exactly the same !! :lol:

Next stop is New Plymouth, NZ .... hope its superior to Darwin .... strange city with strange people!!

Anyway more when I get chance to build it up and test it out in the frame.



User avatar
Tee-Why
Expert participant
Expert participant
Posts: 261
Joined: Fri Apr 16, 2004 12:05 am
Location: Central QLD

Re: ty 250 mono aftermarket parts

Postby Tee-Why » Mon Jul 09, 2012 11:42 am

[quote="

Spend 1 week in WA near Bunbury and Donnybrook/Balingup ... fabulous country, you Aussies have kept that little place a secret!! What fabulous trials country, hills, forests, rivers, rocks its got the lot!! You guys could run a 2-day trial out there just like the Reeth 2-day we have, country is exactly the same !! :lol:

.[/quote]

Hey FF, we'd hold a 2 day trial down there on the June long weekend. It's actually just near Donnybrook in the hills called Kirup. The trial is the Blackwood 2-Day. Pity you didn't give a shout out before you came out this way.

Also the Australian Nationals is held over here this year, closer to Perth, and the WA Championships the week before. Pity I will miss them, as I will be moved over east by then.


I would rather push my twinshock than ride a modern!

David Lahey
Champion
Champion
Posts: 3377
Joined: Thu Jun 05, 2003 7:01 pm
Bike: Many Twinshocks
Club: CQTC Inc, RTC Inc
Location: Gladstone, Queensland

Re: ty 250 mono aftermarket parts

Postby David Lahey » Mon Jul 09, 2012 12:44 pm

Tee-Why wrote:I will be moved over east by then.

8) :D


relax, nothing is under control

Ferretflasher
A grade participant
A grade participant
Posts: 102
Joined: Fri Nov 24, 2006 7:45 am
Location: grimethorpe, UK

Re: ty 250 mono aftermarket parts

Postby Ferretflasher » Tue Jul 10, 2012 4:20 am

Hi T-Y, so pleased to hear it, like I said .... I knows trails country when I sees it !! Went to Kirup but stayed in Balingup with my Aunt, so I shall doubtless be back again next year. Provided your economy keeps growing at 5% then you will keep buying out turbines and I will be out there...... just need to blag a bike ???? :wink:



Ferretflasher
A grade participant
A grade participant
Posts: 102
Joined: Fri Nov 24, 2006 7:45 am
Location: grimethorpe, UK

Re: ty 250 mono aftermarket parts

Postby Ferretflasher » Sun Jul 29, 2012 2:17 am

Hi reader, to continue ... head needed machining to increase compression ratio, basically had to turn down the head to produce a raised combustion chamber to fit some 5 mm down inside the bore. Birkets piston must have been a twin-shock variety with a lower crown height but anyway got round it without too much grief to give me a squish of 1.1mm without the copper head gasket. However I can run with just a thin seal of mastic to the head joint as I have tried this previously without any probs.
Total reduction needed was some 9.6 mm of which 0.6 was for base gasket, some 5 mm off the head and some 3.0 mm off the barrel base.
Anyway much more than I expected but there is plenty of spare to go at and I have arrived back with good compression, scavenge and just about 1mm squish.
To be continued ...!

ps next stop is New Plymouth NZ for a tour-of-duty !!!
Attachments
IMG_4495.JPG
Skimming some excess metal off head to move combustion chamber back down cylinder.



FM350
Expert participant
Expert participant
Posts: 488
Joined: Thu Apr 14, 2011 7:04 pm
Bike: Fantic
Club: Otter Vale

Re: ty 250 mono aftermarket parts

Postby FM350 » Sun Jul 29, 2012 6:27 pm

Was speaking to someone in the know about the TY Mono motor last week, and he has an ex works short stroke bigger cc motor with plated cylinder. Sounded like it would go very well indeed, but apparently no better than a bog stock 249cc piston sport Fantic, and pretty costly to do!

Have had a close look at the TY Mono motor over the last few weeks as I was thinking of doing some development work on one, and it seems to me that the easiest way to get them going properly is increase bore size, and I know of one using various ex works parts thats 340cc, and runs far better than the lethargic stock bikes.

However ex works parts are very hard to find, so I would guess an off set ground crank pin and a different rod to provide shorter stroke, Wiseco TY twin-shock piston, and some careful work with Devcon to make the ports work better, would work pretty well, and not cost as much to do as the other options mentioned above.



Ferretflasher
A grade participant
A grade participant
Posts: 102
Joined: Fri Nov 24, 2006 7:45 am
Location: grimethorpe, UK

Re: ty 250 mono aftermarket parts

Postby Ferretflasher » Thu Aug 02, 2012 11:03 pm

Not quite sure how an off-set crank pin would work, would be difficult to balance me thinks ???? And getting hold of one .... !!
No, I have chosen to use stock parts wherever possible, biggest cost has been Nigel's piston, about 138 GBP all in. Crank came from USA about $35 and so too did flywheel which I cocked-up on, in future buy both items as a matched set. Flywheel was $30 but attracted VAT and duty so that pushed it upto $55. Everything else was found lying about in shed and done by self. Put a new gear selector shaft in from TY as all mine stripped splines. Reed valve mods was price of a beer to welder and if you ignore cost of lathe (thousands !!!!!) then I estimate whole job has cost me 320 GBP. Fibre reeds are about 28 GBP. Lot of work to convert bores to chrome, Shirty did his but Hamilton dont! Barrels I can pick up ebay for 30-40 GBP so not a problem in obtaining doner parts. Beauty of mono is parts availability ... if you can repair them, fortunately engines are bombproof.
I have still to sort out ignition timing but that just means reposition back plate so trigger coil pick-up is about 5 o'clock position but I can play with that once in frame.
Quite how she will run is unknown as yet. The idea of a short stroke is to make it rev like a modern bike which detracts from original Yam ethos where low down torque comes into play but I would think a 340 cc lump would be difficult to handle in the wet, like Kockies Cotswold, needs a darn good rider to exploit it !! Torque band will be narrow and probably sacrifice top end ??
This is purely experimental at moment, if it works then I shall do another with the #3 bike where frame and engine numbers match. This lump will be sold next year.




Return to “Technical help”

Who is online

Users browsing this forum: No registered users and 4 guests