?:-| hello all. I'm new to this group. Would like to know or talk to someone about fitting a 2XT Stator and CDI to my 1KT. I've been told this is part of the unrestricted process. I have had a look at other forums about TZR CDI but can't find the information I'm after.
Any help would be much appreciated.
David.
I think 1KT are not restricted bikes as the power was 45 hp at 9500rpm.
For Japan market they were fitted with 80km/h over speed light but I think this was just a warning for the rider.
There is no wire at the CDI to get the information of over speeding.
I've captured some comparison between TZR 1KT / TDR 2YK & R1Z 3XC (long page so scroll down)
http://rd500lc.free.fr/forum/tzr-tdr-r1z/tzr-tdr-r1z.htm (http://rd500lc.free.fr/forum/tzr-tdr-r1z/tzr-tdr-r1z.htm)
The 2XT model has the same over speeding light and no wire at the CDI to take this information into account.
2XT chambers are restricted with a collar at the cylinder mounting.
Sure the CDI curves are different.
David,
To add to what Olivier said:
The 2XT supplement to the 1KT workshop manual shows 1KT and 2XT ignition characteristics plotted on the same graph. Basically, the 2XT characteristic starts out about 5 degrees more advanced than the 1KT, but the 2XT's rate-of-increase of advance from 2,000rpm is much less than that of the 1KT (the lines cross over at about 3,000rpm). The graph is small so the resolution isn't fantastic, but it appears that maximum advance for the 2XT (at about 3,500rpm) is 22 degBTDC, while that for the 1KT (at the same speed) is 26 degBTDC. From that point onwards, the 1KT characteristic line is always above that of the 2XT. The lines almost meet again at 10,000rpm, but then the 2XT retards at a much greater rate than the 1KT as speed increases further (so the lines diverge again). The graph's engine speed axis continues to about 12,500rpm.
I should state that it is unclear whether the 1KT characteristic shown on this graph is for the 1KT-50 or the 1KT-51 CDI unit. I haven't yet found a published characteristic for the 1KT ignition before the 1KT-51 CDI unit was introduced. The early 2MA and 2MY characteristics are published in workshop manuals and are very close (but not exactly identical) to the 1KT characteristic shown on the aforementioned graph. Despite this, I can only make assumptions about the characteristic of the 1KT-50 CDI unit.
In the absence of definite information to the contrary, there appears to be little advantage in converting from a 1KT system to a 2XT system (unless intended for reasons other than performance improvement). The 2XT system may perhaps offer easier starting and better pulling away from a standstill, but the improvement (if noticeable in practice) would seem to exist only up to 3,000rpm.
I get the impression that Yamaha made a bit of effort with the 2XT to improve the 1KT design (larger reed valves, different cylinder porting), but then built in restrictions (thicker head gasket to reduce compression, rings in exhaust header pipes, different ignition characteristic) to bring the performance back to 1KT level!
From what I have seen, I would tend to agree with Olivier that none of the JDM 1KT models (1985-86 1KT and 1987 2AW) were 'restricted' as such - they share all of the important parts with the various export models of the same years, except for very minor differences in carb jetting (power jet and air jet sizes, as I recall...?).
If you are seeking performance improvement without loss of tractability, here are some suggestions:
a) Fit aftermarket 'street' exhausts with similar characteristics to the OEM pipes. This will lose a good few kilograms of weight, improving the power-to-weight ratio straight away.
b) Modify the air intake system to be more free-flowing (bigger air box, filter with larger area etc.) and convert the carbs to Formula 3 specification.
c) Modify the cylinder head to reduce the squish clearance and raise compression just a little.
d) Modify the YPVS control unit to allow adjustment of the opening point and/or rate of the power valve.
e) Fit a programmable ignition system, to allow full control of ignition timing and power valve opening.
f) Change final drive gearing in conjunction with any/all of the above, if required.
Naturally, there may be pitfalls if the modifications aren't done correctly! I have to say that my own 1KT/2AW is pretty much standard apart from some early SP Tadao Jackal pipes - it is great fun to ride and I don't feel the need for any further performance improvements for road riding. Still, there is nothing wrong with wanting to make improvements to suit your own requirements, whatever they may be - please let us know! :)
Regards,
James
My friends 2ma / 2xt running this setup it was one of the Canadian models.
2xt cylinders and power valves
2xt centre cases and reed blocks
1kt cylinder head and gaskets
2xt cylinders when replated had matched to stock size A 2ma pistons.
1kt/2ma carbs
2ma wiring harness - believe same as uk model
Canadian cdi it's that rare one I think 2my-50 ?
Had jolly moto pipes on it but he went to the K2-tec stamped ones. They are better for the street vs the jolly moto and clear the lower fairing no touching.
It's been running great got like 4500 miles since rebuild.