Understand the concern.
Not sure about the different part numbers but only difference that comes to mind is that in later years the forks (certainly in the UK) were non-adjustable but that was around 2004/5

 

I think that I bought the most lemony of lemon bikes. I decided to check the left fork before buying a new right fork. The left one looked OK from the outside except for the completely blown seal (which I knew about).
It seems that the previous owner rode the bike with no oil in the fork and the preload and damping dialed up to their max settings. This resulted in the bushings in the left fork getting jammed, one under the other, and will not move.
No amount of WD40, slide hammering, hitting with a rubber mallet, or jamming a broom handle in the lower and banging on the floor made any difference. I spent 3 hours trying everything I could think of or find on the forums and I didn't move the fork a fraction of an inch.
I ordered some replacement forks... but does any one have a suggestion for this problem? I would love to just fix one thing on this bike. Thanks.

 

Dude. I know it doesn't help, but I've been there (and will likely be there again)! At least this is happening while the weather is crappy...

 

Well, there's good news and bad news.
The bad news is that the bike is no less lemony, but the good news is that I'm slowly making lemonade.
I spend a good 2 hours last weekend and replaced the front and rear suspension with working parts from eBay and everything went without a hitch.
I also replaced the fuel injectors with some better condition ones from eBay and tried starting it up. It took a few seconds to get going, but started up, rev'd to about 3000 rpm and then settled down quickly to just below 1500 rpm once it warmed up. I put some Seafoam in the tank with the new fuel and when I rev'd up to 5000+ rpm it blew clouds of black crap out of the back but that also soon stopped. Now it seems to start and idle without anything too crazy happening. The new injectors do feel like they work better then the original ones.
I also found the source of the ugly metallic sound it was making previously... the exhaust header is original and in fairly poor condition and I found that the bracket for the #3 cylinder connection is loose even though the nuts are as tight as they will go, and #1 cylinder is missing one of the studs completely. It seems that the rust was holding everything together previously but when it was revving at high rpms it shook everything loose. So now I need to remove the exhaust header and fix that up. Has anyone replaced the studs for the header before? I see lots of threads about studs breaking or just not coming out... but how do I get them out - do they just unscrew using a spanner/wrench?
I feel like all the problems this bike has are fixable, but the list never seems to get any shorter. I'm just happy to finish today with a bike that starts, idles, and has a working suspension that I have confident to ride on safely.
If anyone has any advice on changing out the exhaust studs, I'd appreciate it. Thanks.

 

Lots of plusgas or equiv over many days. Applying heat also helps. I would also drop the radiator to give you room to work in and ideally wheel and forks removed as well.

Your aim is to try and crack the corrosion which has developed due to the metals being dissimilar (steel and ally) if you are trying to remove the studs, if just trying to remove the nuts then that will be plain old rust.

I always try to tighten a little first to try and crack them and then gently back and forth, in all likelihood the stud and nut will come off before the nut comes off if they are as rusty as you are suggesting at which point stud and nut need replacing.

You could try an impact driver, I have managed to free some off as the sharp impacts crack the corrosion / rust.

Or you could get a nut splitter in order to avoid shearing to stud as that is when things go south very quickly, I sheared one on my old 600 and was very lucky managing to get if out by cutting a slot in it and smacking with an impact screwdriver.

If you are really unlucky and snap one close to the head drilling out or welding a nut onto the stud are you only other options.

Fingers crossed they will come out easily....

 

I think this thread has become a kind of therapy for me now.
I have had a successful few days with the CBR. I sprayed penetrating oil on the exhaust header nuts/studs a few days ago and when I went to remove them over the weekend they came out without a fight. A couple needed replacing, but I had anticipated that and was ready with the parts. Draining and removing the radiator, and removing and replacing the headers went about as smoothly as is possible. I found that, true to form, the last guy had no exhaust gaskets installed so I put new ones in with the replacement header.
I also removed the old chain, replaced the front sprocket, and loosened the rear sprocket bolts - but here's where I got stuck. The two rear axle nuts will not loosen. I have used penetrating oil, impact driver, and breaker bar but they won't budge at all. I also found that my new chain is missing the master rivet link so even if I could get the back wheel off I can't complete the job until I get a replacement link.
I'm out of ideas and energy for today - does anyone have any tips on getting the back wheel off? Thanks again.

PS - I bought an imitation DID chain brake/rivet tool for $20 on eBay (its labelled as Python brand but I've seen loads that look the same with different names), and it works really well and is very sturdy - if any one needs to buy a chain tool, I can recommend that one.

 

Fantastic news on the exhaust studs and if course the free therapy!!

As for the rear wheel axle... the rear disk side is the nut to initially concentrate on which you will probably need and extension bar in addition to your breaker bar to shift, the sprocket side is the full axle and sounds like it is seized.

Once you have un-wound the nut a little leave the socket on it and try some sharp hits to try and break the rust build up, then on the sprocket side forward and backward motion to free of the axle.

Thanks for the tip on the chain tool.

 

Slow but steady! Try tightening just a bit before loosening... sometimes that'll give you just enough "play" to get it moving in the direction you want...

 

I had to take a bit of a break due to family visiting and school holidays, but I've made some progress.
Thanks to Al1040 and Doc Samson, I got the back wheel off with a bunch of penetrating oil and the impact driver - once I got a small amount of movement it came off easy. Changing the sprocket was simple and even putting the new chain on wasn't too difficult. Pressing the plates together took all my strength, and I learnt that only a small amount of effort is needed to rivet the new link (I cracked the first one).
I have flushed and replaced the coolant, changed the oil (full synth), installed the new muffler (a chinese clone), and put all the bodywork back on. Yesterday it was running great (after removing the DB killer from the muffler - that made it idle crazy erratic), but I accidentally let the tank run dry and the engine stalled. Today I put more fuel in and thats where the new problems started.
At first it would start but would not idle, it just kept stalling. Yesterday it would rev at 3,000 for a few mins then drop to about 1,500 and juts hold at that. Today there was no high idle. I had to hold the throttle open to keep it running. It kept stalling, and I had to re-start it many times. Eventually it seemed to click and it suddenly started to idle at 3,000 and then drop to 1,500 again after a minute. I took it for a quick test ride and everything worked ok except the bike now idles at 2,000 - 3,000 when in gear, and drops to 1,500 in neutral. Has anyone experienced this? Is it just a hangover from all the crud that was in the bottom of the tank when I let it run dry?

 

Hello again - I am in need of help again and I'm hoping that someone here can give some advice?
My bike starts without issue and will idle nicely until the engine starts to get hot. Once it gets to about 120 degrees the revs drop down to about 500rpm, then it stubbles and stalls if left alone. This means that it was stalling at every junction unless I can hold the revs higher.
I adjusted the idle screw pretty much all the way clockwise and it would sit and idle at around 1500rpm until it got to about 160-170 degrees, but as soon as I touched the throttle the revs jumped up to about 3500rpm and held there. I could turn the idle adjust screw to get the revs back down, but when I do that it stalls outs again. It seems like the idle is either too high or too low, with nothing in between.
I replaced the FPR just recently and I've never seen any sign of fuel coming out of the vacuum side. I also replaced the coolant recently, so the level is correct and the fluid is in good condition. I have checked all the vacuum hoses and seals and I can't find anything lose or unsealed. The battery connections are tight and its well charged, (starts on first crank).
I have read dozens of old posts on the forums with similar symptoms but none had a solution that has worked for me - can anyone help - any suggestions? Thanks.