RE: 1992 cbr1000f - Loss of power
 

There's a positive side to all this (believe it not!) - You've probably heard about what a mission is to strip the fairings/covers etc off a CBR1000F? Well, once you've done it 50 times, I can tell you that it's no big deal. I now have it down to about five minutes work!!!! Next bike is a naked Vtwin!

RE: 1992 cbr1000f - Loss of power
 

Very odd with the detuning by one blockedair inlet and a possible hinder in the downpipes. I wonder why anyone would have done that because it doesn’t appear to be a factory restriction. As far as I am aware of the restricted bikes only have intake rubbers with a restriction that can be carved out to full diameter. The good news is that the bike has not been loaded hard and the fun will begin when things are sorted out.

RE: 1992 cbr1000f - Loss of power
 

Amen to that. As long as I don't have to cough up for a new exhaust system!

RE: 1992 cbr1000f - Loss of power
 

Maybe someone from the future sent us that bike in a time machine, just as a warning of what will come when crazy politicians get to roam freely with motorcycle laws:D


I don´t know what kind of driving licenses you have in Kiwi land, but here in Sweden we have a "middle class" driving license with a 25 kW power limitation to explain it roughly. The bikes here is possible to restrict in power, get it documented on a dyno bench and registrate it as a "middle class" bike. This is what 18 to 21 year olds are allowed to drive, not really sure about ages and the exact power number, but you get the picture atleast. Could this be the case in your bike?

RE: 1992 cbr1000f - Loss of power
 

Hey Swede. We also have a couple of licensing restrictions in Aotearoa (the land of the Long White Cloud) but most of us adults believe they are much too liberal. e.g. You can drive a car at age 15. You can ride a 50cc scotter with a car license. You have to have a full motorcycle license for over 50cc, but are limited to up to 250cc for a couple of years (even if you are 40 years of age). As far as I am aware there is no power restriction in place, and a young rider could buy a hypersport 250cc Suzuki GSXR to Honda CBR250RR and ride the thing at 160+kmh without any problem at all (until they fall off).

Spoke with the Motorbike Shop boys this morning, and they suspect that the ICU or regulator may have been "spiked" at some stage, and while it's still firing the motor on all four, it's possibly not advancing the spark under load, hence the "flat" performance. Am hoping that's the case, and will find out next weekend.

RE: 1992 cbr1000f - Loss of power
 

I don’t think the CBR 1000 F’sECU isable tosense the load and advance the timing differently under load than free reving. If the advance curve is correct when free reving, it will be the same under load. What could be done to make the bike load sensitive, other than restrictions of air intake and exhaust system, is limiting the throttle movement, either in or outside the carbs. Perhaps the throttle springs can have been changed or there is some modification to the vacuum channels that lifts the throttles.

Is it possible to review the bikes history and talk with previous ownersor the company that have detuned the bike? Whatdoes the registration papertells about engine power?

RE: 1992 cbr1000f - Loss of power
 

Okay. Here it goes. No restrictors in exhaust or Inlet, but still we only have aroud 50bhp under full noise. We have a bunch of spare bits to play with next week, so will let you know whgat the fu;;;;cks going on in due course. At the moment, bike is in bits in the workship and I'm having a bit of a cleanup.

RE: 1992 cbr1000f - Loss of power
 

Good idea about talking to previous owners. If the bike has been full power in the past, then it's just a case of eliminating stuff until we find the missing link.

RE: 1992 cbr1000f - Loss of power
 

Through some internet tracing I was able to locate the original NZ owner of the bike when it was first imported in 1998. The good news is that it IS a full power version (120+bhp) and he said he'd seen 260kmh on the speedo and that it was a real "bullet". So, it can really only be one thing now and that's ignition, as all else checks out okay. Pheeeew! Hopefully the spares sent up from Bucket n Bits in Wellington this week will make the difference. Had the full exhaust system off this weekend checking for restriction baffles, and decided to give the headers/collecter a re-spray. There was a bit of surface rust, which I removed with wire brush/wet and dry, but the metal was near perfect - After 15 years, try that in a car? Used VHT Aerosol paint to respray (1350 degrees) and the system now looks like new again. Radiator looks a bit shonky, but is also sound, so that went back in untouched. Will report back in due course on what is becoming a very interesting project!

RE: 1992 cbr1000f - Loss of power
 

Wasn't the ignition timing checked OK, I think you said that in a previous post? And if it fires on all cylinders and without misfiring, the ignition appears to be OK.

Has the carbs been opened and inspected?
Can the throttles move freely all the way to the top?
Are the vacuum diaphragms checked to in order?
When you run the engine, can you see that all four throttles moves upto the same height?
Has a vacuum test been done so the vacuum to all cylinders are known to be about the same?
When the valve lash was adjusted, did they verified that the cam settings where OK?
Has a compression test been done?

Perhaps you don’t want to have questions like this, just tell me then.