1991 yamaha TZR125.... 250 Engine? please help

[shaun6017]

Hello im new her (my first post)

I have a 91 yamaha tzr n i was woundering if i could fit a 250 cc engine onto the bike. N if so what would be the best engine. i.e another 250 tzr engine??? also what would i need appart from the engine??
please help
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[mad4it028]

ide guess the yz250 engine would be easiest as its a single unlike the tzr250 which is a twin
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always looking to buy bikes crashed ,unfinished projects,none runners pm me
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[P.addy]

[Vincent]

You won't get a TZR250 lump in there very easily. CRM 250 might be your best bet. Have a look on youtube, someone I know from another forum has one on there.

[Vincent]

I stand corrected

https://www.racingsm.org/fp.php?project=tzr250

Don't think it will be "a walk in the park" though

[MarJay]

The hard part will be finding a TZR250 engine.

Your best bet is to sell the 125, and buy a TZR250. They are very good bikes and will be much better as a package than a TZR125 with a 250 engine in it.
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British beauty: Triumph Street Triple R; Loony stroker: KR1S; Track fun: GSXR750 L1; Commuter Missile: GSX-S1000F; Cheap project: CBR900RR FireBlade
Remember kids, bikes aren't like lego. You can't easily take a part from one bike and then fit it to another.

[Truzo]

Why would you want to put a 250 engine in a 125 frame ?
You would need to upgrade brakes forks and all kinds of stuff.

Be easier and cheaper just to get a 250 bike.
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Current Bikes: RXS 100, RD 125lc3, RD 350 F2

[binge]

I dont often agree with MarGay, but he has a very valid point.
I considered a Teezer 250 lump when building my hybrid pit bike, but they are like rocking horse shite!

Here is my old Pit bike, which I put a TZR125 engine in. So anything is possible.
Biggest regret of my life selling it.

https://a2.sphotos.ak.fbcdn.net/hphotos-ak-ash1/28192_397612980605_506045605_4039071_1788577_n.jpg

[shaun6017]

ok well thanks 4 all the replys. next question when i first pull away from stand still it seems 2 have no power it jus splutters sort of thing till i hit certain amount of revs? ant ideas?
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[G]

Use the clutch to pull away at the correct revs .

Hard to tell, but 2 stroke road bikes tend to be very 'powerbandy', in that they need to be above a certain rpm to get going properly.
Or, there may be another problem with your bike, of course.
Powervalve stuck open is definitely worth checking, though the later TZR I've ridden, it didn't seem to make much difference either way.

The older TZR250 frame is pretty small and light, so I don't see any real point in removing the engine from one to put in a similar frame that's not designed for it.

[cloric_tzr]

my 1988 tzr 125 has a slight splutter on pull off you can cure it like G says by using more throttle. i also have a dead spot at 4.5 rpm to 5 rpm in ever gear (exept 1st if i use enuf throttle)
due to power valve being open fully i opened it to unlock the bikes full potential (28bhp) but due to a lack of torque and back pressure it splutters when not on the valve. not a problem tho because when you hit the valve change gear the bike doesent drop below 7000 rpm so i just rag it everywhere .
latter models where fitted with the servo to give full power and cure this low rev splutter can be bought for £70+ and finding a servo and pulley system together is like trying to find rocking horse shit.

so in short dont be a pussy and cain it everywhere like it was designed for problem solved. tho it might be worth lookin at the main jet encase some numpty has put a dtr carb on not realising the jet size is 125 but the tzr needs a 180 jet.
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Is the internet connection.

[G]

Yea, on my NSR I would typically pull off at 7-11k rpm to make (relatively) reasonable progress.

[cloric_tzr]

^^ its like scooters there clutch does not engage until 5-6000 rpm 2 strokes just dont have the bottom end torque there all about screaming.
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i dumped my girlfriend the other day! she wouldnt act out one of my fantasy's. all i wanted her to do was come home from work, catch me fucking her sister and join in!!! miserable bitch!
My wifes so ugly, the only thing that goes down on her
Is the internet connection.

[G]

Not specifically 2 strokes, but generally is true of 2 strokes tuned for top-end power.
For instance (from my bikes) the Beta Rev 3 probably has the relative most low down power of the bikes I own, the KTM300 next. The KTM 144 is actually really flat. While the KTM 200 is probably the peakiest of the bikes I own - so quite a range, all 2 strokes.

[cloric_tzr]

i suppose its down to bike design and gearing i.e tzr is a super bike replica in its own respect so it has all the power at the top of the gearing (power kicks at 7000rpm but really kicks at 9000-11000 rpm the dtr on the other hand (same engine) is based on off road bikes so it more mid range (between 7-10000 rpm) any more than that is sounds like its going to shove the con rod through the engine. and so on.
____________________
i dumped my girlfriend the other day! she wouldnt act out one of my fantasy's. all i wanted her to do was come home from work, catch me fucking her sister and join in!!! miserable bitch!
My wifes so ugly, the only thing that goes down on her
Is the internet connection.

[Kickstart]

Hi

TZR125 is a very different bike to the 250 (assuming the older UK models). And a 250 is still going to need to be revved to go properly. If you want more bottom end power then set the power valve back to the low rev position and say goodbye to about 1/3 of the top end power, or get a power valve kit. Otherwise just get used to using all the revs.

All the best

Keith
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[shaun6017]

As of bout 5am this morning my freshly painted mint condition tzr was a pill of ash on the back fields coz some little twats decided 2 burn it when they realised that they were 2 stupid 2 get it started after robbin it frm my house.

Again thanks 4 all your replys
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[MarJay]

[cloric_tzr]

^^^ +1
ouch
____________________
i dumped my girlfriend the other day! she wouldnt act out one of my fantasy's. all i wanted her to do was come home from work, catch me fucking her sister and join in!!! miserable bitch!
My wifes so ugly, the only thing that goes down on her
Is the internet connection.