Part number may be stamped on it? But IIRC, even the new ones still failed prematurely. If its making too much noise, safe to say you should replace it. But if its not broken, don't fix it

 

Are folks comfortable with this procedure vs. removing the valve cover and measuring chain deflection during adjustment? Obviously it is a lot easier to NOT deal with valve cover removal which also includes draining coolant and removing the radiator. But I have done it a few times now; so it is not a huge deal either. Just looking for opinions. Also would be interested to hear how people feel about the manual CCT in general. I read one post where it was stated that the intent of the auto adjuster was to chain the pressure on the chain at different engine speeds, but then have also read that is exactly what should be avoided since it can result in unwanted timing changes. Thanks folks.

 

I'm not sure where the 'timing changes" misinformation started, but I have seen it multiple times here in the last 3 months. The Hurricane, even with a collapsed CCT, does not jump timing. It just rattles like crazy and sounds like marbles in the crankcase on a completely bad one from the chain hitting the guides and being way too loose. The head/cams/gears/chain/guides are tight enough the chain can't jump timing, even at 11K rpm, unless you have more worn out more than just the CCT.

Even when I had my head decked like .040" to raise the CR significantly, with all the other mods I did, and checked it, with everything in place and no CCT installed, it would not be able to change timing unless revved way out due to the captured center gear design. Without any CCT it would have to be high RPM for the chain to get serious momentum so that it could have all the slack in one place. Even when I was putting the final iteration of my engine together with all sorts of crazy internal work there was not enough slack in the chain to pull it off the gear to move 1 tooth.

Not to say you don't have to worry about it, because you still do. If it is too loose the chain guide can wear out very quickly, if it is too tight it will wear out the gears for both cams and the center cam drive gear on the crank. Both too tight and too loose can also wear the chain itself quickly.

If both your guides were worn out, and the CCT was worn out and completely collapsed, and the chain had some high wear, and the teeth on the gears were cupped, you could get enough slack at that point to jump a tooth, but that would be everything worn out at that point, not just 1 item. The CCT is designed to be the "fuse", if you will. A manual CCT lets you adjust it to compensate for wear. The stock CCT automatically adjusts based on engine speed, wear, and oil quality and is basically a hydraulic lifter.

 

Thanks. I honestly wasn't worried about jumping a tooth, I just thought maybe slack in the chain could result in very small variations in timing as the engine pulls-pushes as you get off the throttle. I believe there are a lot of threads that discuss CCT failure possibly resulting in timing issues and even engine damage. If these statements are false, then fine. But if they are true, then it has to be the result of timing changes resulting in piston to valve contact. I don't believe any of those threads are discussing the long term impact of timing chain wear; but an immediate failure resulting in quick off-throttle at high RPMs. It was my understanding folks say a manual CCT is the solution to avoid that problem. Maybe it is all just false information; not sure about that part.

As to my problem, my 87 CBR 600 has hesitation ONLY after it is warmed up at constant engine speed or in off-throttle to on-throttle conditions. Once you are on the throttle (hard acceleration), it runs great. So in a different thread, we were having a debate about CCT problems resulting in this type of problem due to small timing changes resulting from slack in the chain. I am currently exploring this along with carb jetting, cleaning issues (I have two carb racks, one cleaned and re-jetting, one from an 89 that I bought used and fixed fuel leaks on).

 

The carbs are so insanely temperamental on these bikes. I had to plan on a cleaning every single year with re-balancing, and a valve adjustment. I got to the point I could do the whole thing in about 4 hours due to owning the bike for so long, having all the specialty tools, and all the practice. I found soaking the metal parts in pure acetone cleaned it the best, far better than carb cleaner. Make sure none of the plastic or rubber gets near the acetone or you will have to try and hunt a new one down. Use WD40 to clean and recondition the rubber and plastic. You can soak them in a Ziploc baggy with the WD40 after cleaning them up. I would also have to use ultra fine steel wool on some of the needles inside to clean them up.

Another issue with them is the R/R and stator. The stator puts out a very low amount of voltage and the R/R does a poor job. When you got to tip in from a roll it can fritz out and temporarily cut voltage to the battery and coils, causing a short misfire on 1 or both coils, giving the hesitation. Electrosport's R/R and stator and the Factory Pro +6* adapter should be basic maintenance items on the Hurricane to make it run correctly. I ran a few different R/R's over the years and Electrosports was the best.

Coil on plug with stick coils is also a good idea to assist the hesitation if the carbs are dialed in perfect. RRasco did a good write up here on converting to COP about 10 years ago.

On the CCT, I know several other engines from Honda and from several other manufacturers that the CCT will case massive timing changes and engine damage if it goes out. The F2/F3 and newer and the 90's liter bikes like the 929 and 954. My 2011 Kawasaki Concours 1400 was one of them. It could retard/advance a good 10* as the CCT started to go out. If it failed you would have massive engine failure. I had that happen at 19k miles. CCT failed and I bent all 16 valves. Replaced under OEM warranty, but man it never ran as good after that, with tons of other issues cropping up. I sold it off last year. I'm currently riding a 2018 FJR1300.

 

Thanks for all of the info and advice. I have dumped the R/R in favor of a new MOSFET unit and it fixed so many of the problems with this bike. I am at 14V consistently even at idle. This has eliminated most of the inconsistencies. I have two carb racks (one I bought used from an 89) and I am finding the temperamental nature of these things. Pretty close on the 89 carb rack but still have some hesitation accelerating out of idle and again when cruising at higher engine speeds (almost like it is running out of fuel, and then recovering). This carb rack does have a 102 main jet, which is smaller than stock. Currently down to playing with mixture screws, rebalancing and then I may replace the main jets unless it is running perfect. The original carb rack has 112 main jets and doesn't seem to have the hesitation at speed but smells too rich and idles terrible and stumbles when accelerating from idle. I discovered it was missing the washers in the mixture screws which may be related. I took out the CCT and cleaned it but deferring switching to the manual CCT for now.

 

Current problem with the 89 carbs is stumbling from idle and some stumbling cruising below 3000 RPM. Fluttering might actually be a better description. Note that this starts happening only when the bike has been running for 5+ minutes; it has no such symptom while cruising for the first 5-6 minutes where most of that time is without any choke; so choke is not fixing anything. It idles pretty decent although it surges just a bit. Last thing I did on this carb is blow out the jets and replace the pilot jets. I haven't yet disassembled the top half of any of the carbs or changed the balance. Mixture screw is currently 2 1/4 turns out.

So do you think I should continue turning OUT the mixture screw? Or go to rebalance step with sync tool? Replace the main jet with a 105? Or start thinking about top end disassembly?

I can also go back to the 87 carb rack which has been completely cleaned and rebuilt; but this rack shows some signs of vacuum leak that makes me unsure this is the way to go. I has the 'idle stays high' symptom that folks have suggested is a vacuum leak. I can't think where the source would be other than the throttle shaft seals (saw a youtube video about this type of problem on a different bike, but no one on this forum says they have ever disassembled carbs to this level. The carb re-build kit does some with a bunch of orings I didn't use, so guessing those are throttle butterfly shaft seals.

 

The rubber boots from the carbs to the head can crack and leak. Spray some ether around them to see if that is the idle issue. If you have california emissions and didn't get everything off it can also give a slight vacuum leak. The crush washers under the balance screws in the intake tracts can also leak.
One thing I never asked was if you are streetfighter or still plastic covered. The carbs have nothing but problems as a streetfighter unless you block the frame inlets.
Honestly you probably need a 106, 108, or 110 jet since 102 is too lean and 112 is too rich.

 

Rubber isolation boots are new. I am very careful during install to seat the carbs well and make sure the clamps are centered. I installed new copper crush washers on the sync ports. No CA emissions. I have been running the bike without plastic side panels while I have been working on the bike. Everything else is installed and stock, including stock airbox with frame inlets and new air filter. Fuel filter is also new; but petcock hasn't been worked on. Fuel pump is also original but seems to be moving fuel. I have 105 jets (stock ones) that came with rebuild kit I plan to try. Mixture screw changes had little effect; actually turning them out on the 89 carb (with 102 main jet) might have made it worse. I will consider getting some other jet sizes to play with. Do you think altering the pilot jet size could improve transition from off-throttle to light throttle? I was considering trying a 38 pilot jet. Note that this bike does have low restricted exhaust; it is loud.

 

Absolutely the jet sizes can mess with transitions.
This is the Factory Pro guide for carb tuning.
https://cbrforum.com/forum/cbr-600f-...et-kit-127567/