my bikes soooo sloooooooooooow

[neeeel]

i just got my first proper ride on my bike, a tzr 125 2rk, after buying it over a month ago, have ridden it a bit in town, but never had a chance to try it out full speed before now, and im very dissapointed, its slow!!
it doesnt go much over 50 in top gear, unless im goin down hill
and it doesnt rev really over 7 k in the top 3 gears

The engine apparently had a rebuild before i bought it, and im sposed to run it in, could this be why?
I have started raising the revs in the lower gears now, after getting back from my ride, and it is starting to rev over 8k in the lower 3 gears, havent tried it in the higher ones

My bike has a powervalve, i have the kit for it, but not fitted it yet, could my powervalve be closed, and would this make the bike so slow?

thanks
neil

[Paddy Blake]

I would run it in before revving it to much.but you ould clean
out the exaust.

[Kickstart]

Hi

As above, run it in.

However the TZR should manage an indicated 75~80mph restricted (ie, power valve closed).

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[neeeel]

so you reckon the reason for the slow speed is that it isnt run in yet?

[NC30UK]

sounds like either the powervavle is fucked or not fitted properly, or you were lied to and the engine needs a rebuild.

The bike should only start making its power at about 8k.

[Kickstart]

[neeeel]

ok so things i can do to sort it out

check and clean air filter
clean out exhaust
clean powervalve

any others?

how about changing the spark plug?


I had a look at the end of the exhaust, its black, but it doesnt seem too bad
also, im not sure, but my fuel and oil consumption seems very high

[Frost]

Check the vavle is the right way around, not ceased up and opens whent he bike is revved.

[stevo as b4]

Yeah a 12bhp TZR should peak at 7500-8000rpm, and then the power will die quickly, but it should not feel slow to get there. You should easily get to 70mph or more indicated speed and be able to maintain a close to this speed on the open road.

You should firstly service the bike, and check everything one thing at a time. This includes air filter, transmission oil, clutch, carb and oil pump adjustment etc etc. If it does not feel lively, then id check the exhaust system for an exhaust restriction, or a heavy carbon build up etc. Then a compression test can be carried out to see if the motor is healthy.

You are doing the bike no favours by trying to rev it hard when it's not yet run in after a re-build. Why do kids always try and ride a freshly re-built bike flat out and then moan when it fails and is expensive to fix after anyway? By the way, as you may have seen from other posts on BCF about people with broken 125's, do not listen to any advice about what is wrong with your bike from mates, who don't know a thing about them. And if you don't know confidently how to service your own bike, then take it to someone who does know what they are doing and has the tools and equipment to fully work on the machine, instead of having a go at repair's or re-builds yourself.

[neeeel]

ok thanks for all the help

"Yeah a 12bhp TZR should peak at 7500-8000rpm, and then the power will die quickly, but it should not feel slow to get there"

So you mean that I dont need to be too worried about my bike not revving above 7 k?


I will clean the air filter, and check the oil pump, i am confident about doing these, then if things still arent right i will have the compression checked by a garage, and maybe clean out the exhaust, haynes manual says its fairly easy to do with caustic soda

[KyleH]

conisdered the possibility thats its restricted and youve blown part of the restrictor if youve got a 125 there is an official power limit you can have on your learner licence
my NSR rocked enjoy it but dont let it fool you into thinking its a blackbird

[stevo as b4]

Is it a TZR125L (early model, possible drum rear brake), or the TZR125R last model with USD forks?

The older TZR's felt far less restricted at 12bhp than the newer DT125R's which share an almost identical engine, internally. The peak power was 12.2ps at 7500-8000 rpm, and as long as you change up at this point it should keep pulling briskly/steadily at the same rate. If you go over 8000rpm, the power drops away, because the engine cant't breath enough air at this speed in restricted form. Either way it should do 70+mph.

The new DT125R's 1998> don't like revving past 6000rpm, and i suspect that the TZR125R's are also more heavily restricted too, than the early versions, so they won't like revving very much with a closed PV and at least 3 exhaust restrictions and maybe a cat too, at least in the case of the TDR anyway!

[neeeel]

its a tzr 2RK, first registered in 1992, but it could be from earlier according to my local yamaha shop, when they saw the engine and frame number. I have disc brakes front and rear

It revs nicely up to and over 7k in first and second, starts to struggle a bit in 3rd, i can get to about 45-50 in 4th, and then nothing happens after that, even if i change up, it just stays at 50 or just over, and wont rev over 7k

[neeeel]

ok i bled my oil pump to get rid of any air bubbles, it looks like it needs a bit of adjustment, will do that later, also looked at my air filter, the foam element looks brand new, i oiled it a bit, not much else wrong with it as far as i could see.
That only leaves the carb to clean , and compression to check
any one got any other ideas?

[the grim reaper]

Exhaust - de-coke it, especially if the bike has been run in as it cokes up worse at lower revs.

DO NOT use caustic soda though, if you have any aluminium parts in your exhaust, they will dissolve, instantly. Use a 50/50 mix of paraffin and petrol, pour into exhaust and shake well (do not smoke ).

Cheers

Grim
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[simon1221]

Are you sure the fuel line is not blocked? The fuel level on mine was too low so didnt go over 60mph for any great period of time.
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DNA50 (sorry) ->> TZR125l >> GPZ500S

[simon1221]

You may want to fit the powervalve as well, or at least open it. Without the powervalve you have bugger all past 7000rpm.

Check absolutely everything and reset it to standard (mixture, jetting, spark plug etc).
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DNA50 (sorry) ->> TZR125l >> GPZ500S

[dj-999]

need some help with my tzr 50. It starts fine and performs brill on a straight but even the smallest of inclines on the road cause massive power loss. The bike will not accelerate but just boggs down. I have tried everything from checking carb, changed plug, air filter, carb settings even exhaust. I have ran outa ideas hope someone can help

thanks