HELLO

Is a TY250 twinshock engine the same as a DT250 engine, if not what is the difference?

So if not, what other bikes have the same engine as the TY or a engine that will fit (different cc etc)

thanks

Owen

HELLO

Is a TY250 twinshock engine the same as a DT250 engine, if not what is the difference?

So if not, what other bikes have the same engine as the TY or a engine that will fit (different cc etc)

thanks

Owen

Im not 100% sure but I would guess the gearing & cylinder porting is different

I would think the DT is closer to the early YZ rather than the TY

Edited February 9, 201115 yr by Monty_Jon

A DT engined TY just sold on flea bay. Wonder if the buyer knew what they were buying???

So save me the mistake and explain.. whats the difference between the DT and TY engine? help

Edited February 10, 201115 yr by Andy
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So save me the mistake and explain.. whats the difference between the DT and TY engine? help

About 30mph probably. I'm not taking the P but that seems the easiest way to sum up the various differences in tuning, gearing, expansion chamber, carb size etc that would render the DT hopeless for trials use.

maybe you are asking which parts are interchangable?

Unfortunately for would-be parts swappers, Yamaha made quite a few changes to their 250cc dirt bike engines during the time frame that they were producing the TY250 motor, so your question would have to take into account which DT250/DT2/DT3 motor and which TY250 motor you are referring to. Many parts are interchangable but also many are not.

As far as performance-oriented design differences, the TY250 motor has a much heavier magneto flywheel, similar port timing, closer gear ratios for 1,2 and 3 gears, lower compression ratio, smaller carby and very different exhaust pipe design to what was used on the DT2, DT3 and DT250ABCDEFG motors.

If you are talking about twin shock then the crankcases and covers are all different. Some internal parts fit

There are 4 different sets of crankcases, each with diff engine mounts & diff non-interchangeable clutch covers:

1) DT1/2/3, YZ A/B,

2) DT A/B (& perhaps C)

3) TY

4) DT D etc (eng mounts are close to DT A/B but slightly diff

DT A/B/C/D cases are about 1" longer than TY cases, so its not a straight forward engine transplant, but I did read of somebody (foolishly, IMHO) putting a DT400 engine in a TY in USA (where else?) I think.

TY stud spacing on barrel & head is same as DT250 A/B/C/D, & interchange, but diff porting, Comp Ratio

Some internal cluth/primary gear/g'box parts exchange, but not all.

IIRC TY A & DT A use keyed primary gear; B/C/D models for ea use splines (or vice versa)

DT C/D gears were diff (wider) to DT A/B IIRC but not sure if the whole set will interchange.

Don't know if shifting forks & drums are diff/same

Edited February 12, 201115 yr by JC2