2XT Worth it ?

[mellorp]

I've been offered a 2XT in px.  I've had a quick search on the downloads etc. and I can see they are different.

Are they that special to make it worth owning one ? The RD/LC lot seem to think so

[SeaR1ck]

The cylinders are hard plated so lighter weight and have sub exhaust ports different power valves
8 petal reed blocks so different centre cases and such.
Bigger rad
Different swingarm and linkage setup
Different shock fork clevis
Bigger front axle
Different front forks better internals
Different carb settings
Bigger wheels 2.75 front 3.5 rear
Different ignition

That about covers it I believe on the differences. It was considered to be a more track oriented version. 1 year only. So yea good deal snatch it up.

This bike started as a 2ma it's a bit of a mix now. It has most of the 2xt parts. Minus the cylinder head that's still 2ma and the ignition still 2ma so are the other parts clutch trans crankshaft. Carbs still 2ma. But it has the 2xt cylinders pv's cases reeds wheels fork swingarm linkage.

[Mojoracinguk]

I've often wondered the same.
Couldn't see much about the engine upgrades in terms of performance. Couldn't see any stock 1kt vs stock 2xt comparisons.

I assume they were still capped at 45 horses as per the other jdm bikes? Just they had more potential for tunning???

Being a 1kt owner I may be biased, but the 1kt barrels etc were taken over and used on the R1z 250? So why didn't yamaha use the new improved 2xt motor, if it was an improvement?  The r1z was sold into the 90's!

I still get tempted occasionally when looking at ebay or importers and I see 2xt barrels and Reed blocks. But I'm not willing to go down that route....yet 

[Need4speed]

I use the 3MA reed blocks in this 2XT project - plan for my TDR 250

[SeaR1ck]

I've often wondered the same.
Couldn't see much about the engine upgrades in terms of performance. Couldn't see any stock 1kt vs stock 2xt comparisons.

I assume they were still capped at 45 horses as per the other jdm bikes? Just they had more potential for tunning???

Being a 1kt owner I may be biased, but the 1kt barrels etc were taken over and used on the R1z 250? So why didn't yamaha use the new improved 2xt motor, if it was an improvement?  The r1z was sold into the 90's!

I still get tempted occasionally when looking at ebay or importers and I see 2xt barrels and Reed blocks. But I'm not willing to go down that route....yet 

It was cheaper at the time and considered more cost effective with the avg street rider in mind. Not only was Yamaha saving money they thought they were helping you save too. Getting a cylinder bored over was easier to come by than having cylinders replated like now. 

2xt plated cylinders tighter tolerances better cooling as well. More power. Lighter weight. This may also be noticeable in weight feel of the chassis. Unsprung weight losses. But yes it's power is very similar to the 2ma in stock form. But the bike does run cooler and that's with the smaller 2ma style China rad.

Outside of the F3 parts bout as close it gets to like stock tz cylinders for it.

[Mojoracinguk]

I'm pretty sure it would come down to cost too.

Iron liners were proven and it makes no sense going to extra expense, making parts to a tighter clearance, if the r1z was not being sold on performance figures in Japan.

The 1kt barrels were plenty capable in meeting their performance requirements. And as you say, rebores are easy to do back in the day at a machineshop.

So engine wise, we can assume if stock....2xt is similar to 1kt.

Running gear as mentioned is different.
Again I feel the weight saving of the liners is going to be offset by the mass increase of the wider wheel rims and tyres. As it is rotating mass,  they will cause morre effect on handling than a kilo of sprung weight (the liners). Still wider tyres do help a lot. Grip from the tyres and changes to swing arm is again pointing the 2xt as yamahas attempt to sell it as having more 'track potential' but most of us road riders......wouldn't notice a jot 
And as we know today, the wider rims are in demand, if nothing else, because the 1kt rims are a pain to find oe tyre sizes  .

And the news avon are going out of business has stuffed my preferred tyre choice right up 

Maybe I will be after some 2xt or fzr 250 wheels after all

[f3]

look at the spec sheets and you will find the piston clearances are the same on the 2ma as the 2xt 0.50mm to 0.55mm

[James P]

Phil,

It seems obvious to me that Yamaha took some trouble to incorporate improvements in the design of the 2XT engine...and then took more trouble to negate the performance increase by adding further restrictions. Other respondents have mentioned most of the improvements, but here are some of the additional restrictions I am aware of:

1. Ignition characteristic 'worse for performance' than original 1KT characteristic
2. Restrictor rings welded into exhaust header pipes
3. Thicker head gasket fitted to reduce compression ratio

Also, the rarity of the special engine casing, cylinders, PV drums, reed blocks, inlet rubbers etc. makes it difficult and expensive to replace any of those parts which are missing or damaged beyond repair. Having said that, the 2XT model is collectable and sought-after on account of its rarity. Someone like you should have very little trouble engineering out the restrictions with little effect on outward appearance...and so end up with a bike which does actually have some small advantage over a standard 1KT model. If the 2XT you have been offered is in good original condition, it may be worthwhile. However, it depends on whether you want a bike to ride or a bike to just add to the collection. Looking at the machinery you have presented so far, I get the impression that you generally prefer customised bikes to ride, rather than original ones to maintain and polish!

Please show us a picture of the 2XT in question if you have one.

Regards,
James

[mellorp]

Thanks for all the replies. I decided against the 2XT on grounds of it's rarity and potentially not being able to source parts. I've been down the route a few times and TBH I'm getting a bit tired of it. I'll stick with what I know & understand. No new tricks for this old dog.

[chippy]

One other minor difference was the colour. Pearlescent white and a different red 👍

[James P]

One other minor difference was the colour. Pearlescent white and a different red 👍

True, but I think the export-model 1KT-based TZRs from 1988 onwards had that same colour scheme. The 2XT was however also available with blue 'speed blocks' and white wheels (photo here: https://www.motorcyclespecs.co.za/model/yamaha/yamaha_tzr250%2088.htm), also:



Regards,
James

[oldiggy]

Hi James when you compare those two photos in blue and white the single seat and wider rims make a massive difference to the look.

[James P]

Hi James when you compare those two photos in blue and white the single seat and wider rims make a massive difference to the look.

Yes, I agree. The fact that the rear wheel is 40% wider (and the front nearly 30% wider) than the earlier models illustrates how much difference the wheels make to the appearance.

Regards,
James

[jools]

2XT was an official import into the UK (likely other countries too) so it's highly possible it wasn't restricted.

[James P]

2XT was an official import into the UK (likely other countries too) so it's highly possible it wasn't restricted.

Are you sure Jools?? I know that Europe got the 2XW1 (1988) and 2XW2 (1989), both of which had '2MA' frame number prefixes. These seemingly had the following features:

1. Same colour scheme as white & red 2XT (I don't know if any other colour schemes were offered on Euro export models for 1988 or 1989)
2. Same updated rear suspension as 2XT
3. Same small changes to carburettors as 2XT (i.e. screw instead of pressed-in ball to blank the atomiser air supply hole in the bell-mouth)
4. Original 1KT iron-sleeved cylinders
5. Original 1KT six-petal reed blocks
6. Original 1KT 'narrow' wheels

I had always thought that the 2XT model was JDM only (and only appeared in UK by 'grey import' in the 1990s) - please let us know!

Thanks & regards,
James