Project T20 250 Dirt Tracker.

[firko]

Steve....could you measure your engine's total length for me please? If on the long chance it's capable of fitting in a PRE '70 TS250 frame I'll donate one to the cause and we can rake it at the same time as Pete does our TM/TS project bike frame.I suggest The TS frame as it's already in the ballpark in wheelbase and geometry, needing only a 26degree rake adjustment. Aftermarket bodywork and/or proper dirt bike bodywork fits and proper dirt wheels and forks are already there. I think I can also donate a pair of wheels to suit if needed. If, for some reason the engine doesn't fit the TS frame I can donate yet another, more exotic frame that might also fit the bill but....first things first. PM me the overall dimensions of the engine and I'll see what it fits.
                                                                                                        ......just another thought

[yamaico]

I think Mark is going to wear you down in the end Steve. Pretty good offer - sounds like a good plan to me.

[Curly3]

Overall length = 440mm and height = 380mm.
I'm thinking again, if I go down this line I should probably look for another engine because it'll be a shame to split up the matching no's of this bike.
My head hurts again.

[firko]

Steve....revert to original plan my friend . The TS 250 frame cradle measures only 400mm in length, the DT1 380mm and my choice for a plan B, the American Eagle/Sprite frame I've got kicking around only measure 400mm or so. I'm guessing the TM/TS 400 frame would accept the T20 motor lengthwise but unfortunately it doesn't fit into pre '70. Sorry mate, I guess it was a good idea at the time .

[Freakshow]

Go with plan A, its just another bike, just ride it as it is, if you place 2nd at the NAts in your class then you can go about tweeking the frame.  Get it on the track first, Ride have fun, then get all Fussy if it amounts to anything.  Otherwise its going to shit in your shed for another 20 years with the best of intentions and a lot of spiders.....

[yamaico]

Go with plan A, its just another bike, just ride it as it is, if you place 2nd at the NAts in your class then you can go about tweeking the frame.  Get it on the track first, Ride have fun, then get all Fussy if it amounts to anything.  Otherwise its going to shit in your shed for another 20 years with the best of intentions and a lot of spiders.....

We'll be looking at first place here Kerry
Looks like plan A Steve. Had a look at the frame photos again and it will be a piece of cake to de-rake it. The motor is the same bore x stroke as a CR125, so we'll spec the motor, pipes and carbies that way. Throw in some head mods and I don't think you'll have any problems seeing close to 40 useable hp.
We don't want this, as Freaky would say, shitting in the shed for another 20 years.
Pete

[firko]

How hard would it be to twingle the T20 Pete? I seem to recall Frank doing it to some twin or other a couple of years ago.
Remember also chaps that my bikes will be in the same pre 70 division so let's not make it too bloody fast...OK?

[vmxrider]

Whats a twingle, and why would you do it?

[mainline]

Whats a twingle, and why would you do it?

It's like a savoury pretzle. Flattrackers have been using them as a fuel additive for years

[piney]

Hey Slidez I
more than happy to help out with paint if you wannna look as good as its gonna go.

[firko]

To twingle an engine is to rephase the 180 degree crankshaft to allow both cylinders to fire at the same time every revolution, essentially turning the egine into two singles...a 'twingle'. It was common to see Suzuki T20's and other 180 degree twin's crankshafts rephased to fire both cylinders at the same time in USA flat track back in the day. When he was experimenting with 2 stroke Suzukis on the dirt track, master tuner Erv Kanemoto created "tringle" three banger on his Suzuki triple tracker as well as 'twingling his T20 and T500 twins.
Below: Erv Kanemoto's three cylinder Tringle

[yamaico]

How hard would it be to twingle the T20 Pete? I seem to recall Frank doing it to some twin or other a couple of years ago.
Remember also chaps that my bikes will be in the same pre 70 division so let's not make it too bloody fast...OK?

Quite common on four stroke twins, but I'm not sure about a parallel two stroke Mark. I don't know how the crank goes together on a T20, and the right balance factor would have to be calculated and implemented. It's the big bang theory and significantly changes the characteristics of the engine, whether for better or worse would remain to be seen. Probably worth just trying it in stock configuration and getting it to handle and see how it hooks up. Food for thought, though.

[EML]

T500s for sidecar x and speedway outfits were modded that way(twingled) to give better drive and it is definately the way to go or you wont get that 40hp to the track. You will find the back end will keep wanting to come past you-at the end of the straight when you least expect it.
 

[yamaico]

To twingle an engine is to rephase the 180 degree crankshaft to allow both cylinders to fire at the same time every revolution, essentially turning the egine into two singles...a 'twingle'. It was common to see Suzuki T20's and other 180 degree twin's crankshafts rephased to fire both cylinders at the same time in USA flat track back in the day. When he was experimenting with 2 stroke Suzukis on the dirt track, master tuner Erv Kanemoto created "tringle" three banger on his Suzuki triple tracker as well as 'twingling his T20 and T500 twins.
Below: Erv Kanemoto's three cylinder Tringle

You posted as I was posting Mark. From your post it would appear that it is quite doable. If the T20 has a splined crank with an even number of splines then it would be no problem. The only thing to consider is the difference between flat track and short circuit, with our version being more stop go and hard braking and accelerating. It's probably worth a try as an experiment,
Pete.

[firko]

I remember reading a very interesting article on the 'net about Kanemotos experiments with twingling his engines, especially the T20 and later the T500. Apparently both were fast and got the power down really well. The problem with the triple was finding a sympathetic balance factor and starting the thing. I'm going over to the Grand Poobahs place on Tuesday Pete so I'll get in his ear and see what he knows about this twingling black art .