Suggestions For My "New" 1991 CBR1000f
 

Hey everyone, I just bought my first "fast & tuned" bike and it happens to be a CBR1000f - I think I'm in the right place :) For the most part I built/bought/rode/sold HD V-Twins over the past 25 years. The Hondas and Suzukis always stayed in the garage more for some reason - Maybe because the ones I had were all lackluster small displacement cruisers and nothing spicy. So I picked up a sweet older Goldwing Aspencade to couch-ride to FL this winter and got the Honda bug - The Wing is a marvelous motorcyle, I love it. Whirrs, purrs and handles great. It will take me the 2050 mile trip in style - I can endure about 1000 miles on an FXR only to stop between fillups - Definitely shouldn't feel as beat riding the Wing. And don't get me started on the radio lol!

Anyway, I'd like to give you some specifics on the kind of bike I've always wanted and just never got around to it. A whimsical purchase but it was fueled by Honda research and my love for older motorcycles (but not too old!). The CBR, kind of downplayed from what I've read, looked to have the solid bulletproof reliability combined with a higher speed thrill that I was looking for. Perfect for a 48 year old dude that doesn't want "issues". So I impulsively snapped one up - That's how I roll...

(I'll post photos when I receive permission, but first help get me loving this thing! I've worked on a lot of bikes and this one is a little alien to me starting out.)

1991 CBR1000f - Lovingly called a "Hurricane" - Yes, I got me one!!
$1,000US - Hence the impulse part, normally would have tried for 700 being right before winter but I had to have it and it was a long ride home.
40,500 Miles - No history or helpful knowledge regarding the previous owners. It does not look loved, so clearly it was not loved.
All safety features and lights functional, and has what we call in Maine a "State Inspection Sticker"
New chain, sprockets, caliper pads & tires. The rotors look good - Plenty of meat on them and no grooves.
No obvious hand play in axles, swingarms or steering yoke - Just checked enough so I would dare ride it. Much more to look at.
Seat is new, plastic has some glued together cracks, couple broken louvers on the sides, otherwise looks good in the dark 20 feet away
Wheels are brake dust dirty and should clean up.
Charger is chargin', sparkers are sparkin', runs on all four, clutch is clutchin', all that stuff seems good.

A laborious first thread, sorry, but now down to the engine, which concerns me. I mentioned bulletproof but I don't know, man. 40K is a turning point for a lot of things for a CBR I guess. My inspirational research was good, technical research was not. The noises are normal from what I'm gathering and it does quiet down a lot after a few minute warmup, but to the extent of continued use I'm not sure. So far after a tank spiked with Sea Foam, at 5K RPM and below it's somewhat of a turd that doesn't idle right without the choke cracked a little. After 5K its "OMFG I love it!!" Scared me enough to buy my first helmet in 20 Years. And I haven't even breached 8K RPM yet.

So I have to clean the carbs to get the obvious idle circuit unclogged and smooth again. Then put them back on. Then sync them.
The CCT at least needs to be replaced/cleaned, most likely chain too. I did research and watched You Tube videos about why a manual tensioner is not a good idea.
Valve adjustment is necessary.
There is a rattle at exactly 5K RPM, not sure if something on the frame is loose, or unadjusted valves yet, or cam chain.
Don't have the panels off so I can't tell if some of the rattle is lower end, indicating chain noise from other components I guess?

Normally at this point with something familiar to me I would take the engine out and just "do it" which would involve checking tolerances and if everything was reasonable replace rings, bearings, pumps and clutches. Or find another motor. Did I mention you can't find any parts for this thing?

Is it worth just cleaning/setting up the carbs and doing the tensioner/chain, and is there anything else I should know about? Also, if there is alternator and oil pump chain noise, what happens if I just let that ride?

Thanks for reading if you got this far!

Mark

Hey Mark,
For what it's worth, I've got one on the bench with similar mileage right now and the alternator chain / oil pump chain don't seem to be particularly failure-prone. Not saying they couldn't be, but I would start elsewhere first (ie, the timing chain). A stethoscope could be your friend here to find the rattle but as you describe it it definitely sounds like the timing chain. Pretty common for Honda's of the era and after obsessing about the noise myself, I couldn't find a lot of reason to worry about it. I think they just run a little loose (my 82 interstate is even worse)

What does compression look like? Will you be doing the engine anyway? If not I'd do the valve adjustment, mic the cams and inspect cam journals to get an idea of general wear, and check out the cct while I was at it. If you see evidence of oil starvation or abnormal wear, or if compression is low, apart she comes. In my experience, they're fairly tough engines and I didn't see a lot of wear on mine so if it's been cared for she'll serve you well with minimal headaches

Parts can be tricky but I was able to get an OEM top-end kit, seals, bearings, and rings from the states without too much trouble. Standard bore is much easier to find than oversize, and larger components (crank, cams, pistons, cases, etc.) won't typically be available new. You'd need used for those. Supply does seem to be tightening so best to check availability before undertaking a rebuild

Either way when you do the carbs make sure to check out the fuel pump. If she's hesitating that can be another factor

Also with old bikes like this, it's a good idea to re-torque any critical chassis bolts (motor mounts, brake pivots, axles, steering head, swingarm, etc.)

I'd say fix the minor bugs, give it an inspection, do the valves and replace the obvious stuff, then ride it as-is for a season at least. There's a lot to like about these bikes

Just my 2c

That is great info, thanks! It will most likely be my course of action to just clean the carbs and adjust the valves for sure before I get froggy with that engine. Very key for you to mention checks for oil starvation, mic the cams, fuel pump check and especially the compression test. I'm definitely cleaning or replacing the CCT, read that cleaning it is perfectly fine if not replacing the chain but it's only $130 and a chain is $50 so on the fence about that. If tolerances check out, maybe just buy those while it's apart?

And good point to to retorque the critical chassis bolts. I already got my repair manual, Honda common service manual and owners manual downloaded and ready to go (The owners manual, often overlooked, already helped me get my seat removed lol!).

Thanks again tentacleslap, I'm already feeling better!

Mark

Hi Gronk, welcome to the forum.

The advice from Tentacleslap is good, with the exception of the fuel pump, in as much as it doesn't have one. The 87/88's do, but 89's on are gravity fed :D

They are great reliable bikes, the only weaknesses were the R/R, the cam chain/tensioner and if the headers are original they can rot through.

I bought mine with 32,000 miles and sold her earlier this year with about 60,000 miles on her. The original cam chain rattled when she was cold, but quietened down once she warmed up. In all the years I've known these bikes, I've never heard anyone report a cam chain actually failing, doesn't mean it can't happen, but they're tough old engines :)

Thanks Hawkwind, I see why there is an aftermarket exhaust on it now - Mine has a tomato can looking thing similar to what the kids put on their junky little cars. I probably get .0025 more horsepower but it's ugly.

One more ride today before the panels come off. It is running better and sounds quieter after the 182 miles I've put on it. The previous owner definitely let it sit too long. Sea Foam in every tankful, and I put some in the oil too. The only thing I've noticed so far is a couple drips of antifreeze out of what I think is the reservoir tank coming from the right side of the bike. The oil is clean and exhaust is clear so probably just a leaky hose or something. I really want to crank this thing up but it's not ready for it yet, so far just easy riding with occasional acceleration spurts.

I feel stupid asking, but what is R/R? I don't want to be riding around with a bad one of those whatever it is :)

:icon_worthless:

I'll add checking your wheel bearings and steering tube bearings as well. No play doesn't mean no wear

cheapcycleparts.com and bikebandit.com are still viable places for OEM parts, plus the all valuable fiches.

Gunk, you are right, I'm going to post some pics of the old 'Cane even though she's rough! And thanks wofferdog, I'll check those bearings after one more tank of fuel. Put another 100 miles on her today :) Regarding parts I'm glad to have a couple more sites to look at.

It looks like the Sea Foam has opened new worlds on the top end and way less choke at the stop signs. I can't believe I haven't ever owned a bike like this! And now there is only a rattle after 5K rpm regarding the timing chain noise when warmed up. I wonder if it's something loose on the frame instead. Maybe one more tank of fuel before the panels come off. It might be a decent day again tomorrow...

Some pics of the dirty bird! That's my mint wing in the background on the first pic.

A couple more