Getting slower with age

[Whosthedaddy]

My ZXR according to the figures in 1991 (when new) has 100 bhp, will do 0-60mph in 3 secs and top out at 150mph

Now the bike is 15 years old, it doesn't feel this spritely

How much power do you think a bike loses as it gets older? How can this power be reclaimed?
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Current : MSX 125 Past : CBR 900RR Monkeybike : c50 LAC : ZXR750 H2 : FZR600 : ZX7R P3 : YW100 : TRX850: Trophy 900 T309 : GSXR 600 L0: Monkeybike : XJ6S Whosthedaddy

[base]

i also have zxr H2 and all i can say if it does not feel rapid something is wrong maybe you need to rev it a little more, by any standards in my opinion they are quick bits of kit, i dont know what has been done to your bike but a good quality aftermarket exhaust and dyno jet kit will make a difference, and i cannot seee any reason why if it made 100bhp 15 years ago why it should not be making that now, unless its a ill little puppy

[kb-zxr]

150mph? I would have thought it was higher, as the 400s aren't far off that. I would have guessed at a good 160-165mph by looking at other 750s.

[Whosthedaddy]

[WR450_geezer]

On TopGear they did the test with old super cars and I think they were around 30-40 years old and they were originally around 200bhp but through the years and to the present day one of them had lost something stupid like 100bhp!

WR
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[base]

yes this is true top gear did show some had lost loads of BHP but they did run like utter dogs

[kb-zxr]

[mchaggis]

Bearing wear, camchain wear ('lengthened' chain means dodgy cam timing), worn cams/ followers, worn valve seats (loss of compression) and springs, worn piston rings + bores (increased slap and blowby), worn clutches, worn pretty much everything.

To regain lost power, renew everything which is worn, which includes a rebore and new pistons, new plugs, new cams, valves, cleaned ports, new bearings, etc etc etc. Hell a new radiator might even help things.
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[Barry_M2]

[Silver]

[loply]

Might be worth getting the bike dynoed, its not unusual to have problems with a bike that result in a large loss of power.

Wasnt there somebody on here who had a Triumph that was giving out 80bhp when it should have made 110 or something?
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Yamaha SZR660 Caution to the wind, the throttle pinned!

[Type_Mo]

I thoguht engines get a little quicker as they do more milage.

but then the engine could be getting clogged with carbon deposits or whatever.

or maybe your soo used to the bike it feels slow?
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[mchaggis]

[oldgit]

I've got a GPX750 (basically the same engine as the ZXR, but only 106bhp) which has done just over 50,000 miles. A GPX750 was tested by Bike in 1987 with a top speed of just over 150 and it did the quarter mile in 11.5 seconds with a terminal speed of 120. I took mine on the Bulldog run what u brung and even with me riding it did 11.8sec and 117mph, so I don't think it's significantly down on power.
The ZXR develops slightly more power (112) and is 8Kg heavier, so it should produce more or less the same figures - the 1/4 mile time was supposed to be 11.3.
Things like carb balancing, dirty air filter, worn spark plugs, dodgy leads, valve adjustment, dry drive chain etc. can reduce power by quite a lot.
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grumpy old man

[Visitor Q]

I would imagine a 1980s RGV250 without any miles on it makes the same power now as it did then.

Its mileage and wear.

Im experiencing something similar to this with the smod.
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[Kickstart]

Hi

Wear and servicing will affect it. In addition to what was mentioned above, the drive chain is probably past its best, eating a bit of power, air filter in need of replacement, jetting is probably miles out from wear to the attomiser tubes (and probably someone fitting a race can in the past and not setting it up right), carbs out of balance, wheel bearings are probably past their best, airbox not sealing to the carbs, double bubble screen making the bike taller at the front, brakes dragging a touch, coked up exhaust, etc.

Even really silly things might have an effect. Throttle cable for example. If it is getting old then it will take more effort to open the throttle, which subconciously will make the bike feel slower.

Also, not sure how much experience you have, but to produce that kind of performance the bike needs to be thrashed on full throttle at the red line, rather than half throttle at the red line or full throttle and changing up at 7000rpm (both common).

[R6jonny]