New to me TZR250

[m in sc]

yup. no carb heaters.  got carbs off last night.  they are cleaning now, def need  new intakes soon though..

[mnein]

Man. Way cool.

[busa1300]

3xc is R1-Z.

Another bike that used the 1KT motor.

Makes sense, as I don’t think the early TZR had the carb heaters like the later TDR and R1-Z.

Must have swapped the the 2XT for a 3XC somewhere in its life.

[m in sc]

this thing looks completely mechanically unmolested, i would he highly surprised and doubtful if the motor was ever swapped, there's zero wrench or witness marks on any of the motor bolts.  The only history i know on it is it came from japan from a collector over there. is it possible? i guess... but id find it unlikely. but im sort of out of my knowledge element here on specifics.



 

[RDFL]

Can't beat a Marlboro paint job.

[busa1300]

Here are the various paint options and serial range through the years for each version of each model

http://pure2strokespirit.net/redandblueftp/model_history/tzr250/tzr250_model_history.html

If you need parts

http://pure2strokespirit.net/redandblueftp/download/1KT/1KT_2AW_parts_catalogue_jp.pdf

If you have a 3XC engine, the intakes and carbs may be different than the 1KT / 2AW

[m in sc]

i APPRECIATE THAT. webike has a bunch of stuff for it as well. the intakes are the same as the tdr from what ive seen.

so looking very closely at it, it does appear that the rear motor mount bolt, indeed, has been taken out at some point. 

so.. what motor is this then?

this link tosses in the 3xc with the tzr, but as a 91? do i have a later R1Z motor in there? Is it some weird japanese market stamping?  I seriously would like opinions on this as i'm a bit out of my element as to identifying this. oh, and no carb heaters. like said, everything looks dead stock so im totally confused.

 http://pure2strokespirit.net/redandblueftp/download/3XC/index.php


pics for id:

[pdxjim]

3XC is absolutely an R1Z.

No VIN on cases is standard for JDM bikes.

Join the TZR FB group and start asking questions.

[m in sc]

will do.

in some reading, appears this (r1z) is a 40 hp motor.. at 8500 where as the 1kt is .. 50? at 10k? not sure how much truth there is to that, im sure some, but , internet.. anyway, thats fine, and the guy i got it from def didn't know the discrepancy, so i'm not mad at all. just trying to figure out what's in my hands right now . as far as collectability and resale, really don't care as much as most would.  In some respects... if its a bastard bike, that give me freedom to be more open to mods.

the deal isnt 100% locked in stone. in a lot of respects, having one i can mod guilt-free is a bonus to me. that being said, how much more tame -is- the r1z motor? and aside from (porting i would guess?) what are the differences? 

 

[pdxjim]

I believe they are all the same really.

Just some subtle differences between models.  Trans ratios, CDI and loom, carb heaters etc, but the cases, crank, cyls, pistons etc are all the same.

[busa1300]

I know the differences between the 1KT and the 2XT, (2XT is noticeably different) but not sure of the 3XC (more like 1KT).
If the upper case has 3XC cast (not stamped) into it then there is a difference.
JDM bikes became restricted to 45hp around/after 1989. In 93 they were restricted to 40 hp. Most restrictions were in ignition box and carbs, pipes
So I would first look into the carb jetting and compare it to the parts fitch to see what they were off of.
For the TZR 3XV models, the standard bike and RS version all had 28mm carbs, the 91-92 SP had 36mm, the 93-94 SP had 32mm and the SPR had an oblong 32mm.
LOTS of variations from the factory, and not sure if there were different sizes for the first gen  TZR. The bike was sold in Canada for a year or two, and all those were in unrestricted form I think…could be a source for upgraded parts.

Impex and megazip are direct from Japan parts warehouses where I get most my stuff.

[pdxjim]

... and yes, your bike does indeed have the carb heater head.  It just has been bypassed with that loop of hose from the therm housing to the head.  If you have 3XC/2YK carbs, you should see the corresponding in/out water fittings on them.  Coolant flows from the therm housing into the left carb, over to the right carb, then back to the head.  Useless in your climate.

Much cleaner to just remove the banjos and hose, and replace with button heads and copper crush washers.

2YK and 1KT don't have a YICS boost bottle either, just a straight crossover between the intake boots.

[m in sc]

Jim, admittedly i hadnt dug into the cooling system yet. I see what you are saying. (i did just get it running last night) but theres none on the carbs themselves.  The carbs were super gummy.

carbs are, for sure, tm28s, i did measure them. and it is jetted as a TZR, 230 main jet, 20 pilot. (from what i found).

it looks like somebody may have just swapped the lump itself. 

i will definitely plug the coolant ports down the road, sooner than later.

and the mark is stamped into the upper case, not cast in (at least not anywhere i found). From the little bit ive read, when the parallel twin was replaced by the v twin for the TZRs, they then started using this motor int he r1z with the restrictions as mentioned. Like said, everything else seems unmolsted so far. so, maybe i got lucky. I'm by no means a purist but i'd hate to be down 10hp from what it could be.
 

 

[busa1300]

Some final parallel  history
Will need a web translator.

https://mr-bike.jp/mb/archives/3714

End of the line for Yamaha 2 stroke street bikes...
https://mr-bike.jp/mb/?p=3775


I had some 2XT engine pictures, but can't find them now....only found this one showing cylinder markings
2XT...

[pdxjim]

Looks like you’re getting some answers in the FB group.

These are the pipes you want. Hand hydroformed by Martin Johnson in the UK. Super nice, humble genius. Modestly priced as well. He makes road (midrange) and race versions.