The Saga of my First CBX

[erik]

All,
Thank you for approving me to join this site. It is with great happiness and sorrow that I became a member of this site. I finally, after several years or dreaming and looking, have bought my first CBX, a 1981 Prolink, all original, with 54 hundred miles on it! This is the nicest classic bike I've ever purchased and had big dreams of riding it all over Texas as my go to tourer. I purchased the bike sight-unseen from a dealer in Dallas who specialized in classic bikes. Joining my CBX in his shop were several SOHC Hondas, a beautiful KZ1000, a Kawasaki Mach1 Triple and many late model bikes. I live in San Antonio Texas, and hitched a ride up to Dallas today to pick up my new ride. The bike has a rather aggressive clutch chatter, which was disclosed to me and a portion of my original purchase price refunded, so that I may have a professional install it if I wished. I signed the paperwork relevant to the bike and sped off, happier than a clam and genuinely impressed with the performance of this machine. The six sounded beautiful, all carbs singing a song Sichorro Honda would've loved, no problems at all. It had acceleration and power I had never experienced on a classic bike before, I can say while not as fast as my former ST1300, it did pull a huge smile on my face. With a full tank of gas, I pointed her south and sped down 35, having a bit of fun with my newest ride. My triumph however was short lived, as after approximately 43 miles, the oil pressure light illuminated and the engine stalled. I pulled the clutch in and pop started it at speed to find that the oil pressure was back and the engine ran about 10 more seconds before the light coming on and it stalling again. This time I was at an exit and I pulled off and coasted to a stop. The battery was dead and the engine wouldn't crank. Fearing the worst I began pushing my bike in the hopes a good Samaritan would stop and give me a jump. Eventually one did, we jumped the bike off and I rode it to his house some 2 miles from when I met him. While my nerves and body cooled off in his AC living room, we charged the bikes battery, hoping that low voltage caused my woes. After about an hour, with a fully charged battery and all the lights disconnected, I restarted the bike and set off again, hoping that my troubles were behind me. In fact they returned some 5 miles down the road, this time, I heard the engine making some terrible noises before it staled and I popped the clutch again, the engine again sounded great until it didn't and stalled again. I got to a truck stop and my friend I had met earlier, came with a trailer and towed my sorry butt and dead bike to Austin, where a gentleman I had spoke to on Facebook, who was a member of a group I'm in came to my rescue and took me and the bike home. I'm broken hearted now, and it is with great disappointment that I ask anybody who has any idea what happened to please lead me in the right direction, so I can get this beautiful Honda back on the road. If it makes diagnosis easier, The oil was clean, filled to halfway on the dipstick, and looked good, if a bit thin.

[daves79x]

Welcome and thanks for that introduction, though a sad tale for the moment. From all you've said, it could be a lot of things. It sounds like your bike was not charging at all and the 'clutch chatter' you were hearing might well have been the alternator clutches chattering due to a bad bearing. The alternator may have finally locked up. The actual drive clutches in the late models are fairly quiet and don't usually 'chatter', unless carb sync is way out.

Your bike may very well be a 'school bike'. It is a low mile bike, but may have been worked on by vo-tec students and not assembled properly the last time. That is always my first question about an '81.

Anyway, take the alternator off and see if everything in there is crispy. If so, then you'll have a bit of work to do there, if not, deeper surgery will be necessary.

You need to find a good CBX specialist in your area if you aren't comfortable going into the bike very far. But we'll certainly help you diagnose what you find with the aid of pics and good descriptions.

Dave

[erik]

Dave,
The previous owner of the bike had swapped out the original alternator for what I believe, is the alternator from a newer Kawasaki using a kit I had happen to see advertised online before purchasing my bike. The chatter seems to go away when the bike is put in gear but returns in force when leaving a stop. it does go away after you accelerate a bit only returning when the clutch is again pulled in.

[daves79x]

OK. Well then, it sounds like something has come loose in the clutch housing. The clutch hub nut would be one. Or something was incorrectly installed there. I'd drain the oil and pull the sump cover. What's there will likely tell you what the problem might be.

But all this still doesn't explain why your bike is not charging and just 'quits'. Does the engine lock up causing it to quit, or is it due to a discharged battery? In any case, don't run it again until you have checked the sump and pulled the clutch cover to investigate. These things get real expensive real fast if something like this goes unattended.

Dave

[erik]

Dave,
I was under the temporary impression that the bike might have some sort of kill switch connected to, or triggered by a loss of oil pressure. I will pull the sump to see whats going on in there. The PO said the oil had been changed, could a lack of the washer in the oil filter housing, coupled with a thin viscosity oil cause a complete loss of pressure when the engine warms up? If the dealer I bought it from was anything like the dealer I used to work for, I would have assumed he threw in the cheapest 10W-30 oil he could get on sale, and possibly not being familiar with the bike, left the washer out when the filter was changed. I'm just speculating here, as I have to fix the brakes on my 1960 Olds Dynamic 88 to get it out of my shop before I can tear into the CBX. Is there a kill switch connected to the OPS? this wiring harness looks bone stock.

[erik]

Also, does anybody know of a CBX specialist in the San Antonio area that may be of some assistance. If worse comes to worse and I need a new motor after this ordeal, I would like to know where to source one.

[daves79x]

I'm still confused as to whether the engine is actually still running when the oil light comes on. If so, you definitely have some looking to do inside the clutch cover. Now my guess is that the clutch basket was not seated into the oil pump drive gear fully. This results in possibly some broken teeth on the primary gear/clutch hub and these parts could catch in the oil pump drive chain and de-rail or break it. There is for sure something rattling around loose in there and there will be evidence of that in the sump. The filter spring missing would cause no problem (most CBXs are running around without them). Oil type is not a problem either. Get the sump drained and checked and the clutch cover pulled. Something obvious there.

Dave

[FalldownPhil]

Hi Eric,
Sorry to hear your tales of woe. There is a CBX guy that I know that is in New Braunfels, TX. I believe that is not terribly far from you.
His name is Jeffrey Gadiant AKA Jebbysan on the forums. Let me know if I should try to get the two of you together.
Best,
Phil

[erik]

FalldownPhil,
That would be great, New Braunfels isn't far at all.

[FalldownPhil]

Erik,
I have talked to Jebby and he is expecting to hear from you
PM sent. Please keep us updated on what you find.
Best,
Phil

[EMS]

Erik:

Let's assume the noise and your engine stalling are not the same problem. There is no such thing as a "kill switch" at low oil pressure.
But you could have an electrical problem, that affects a couple things. It could cause your ignition to go off and also ground the oil pressure circuit - which will make the light go off. Just a theory. Difficult to say without getting hands on the bike.

[erik]

EMS,
It's possible, the bike came with a complete hacked up harness, possibly the bike was rewired improperly? It only died when the oil pressure dropped though.

[EMS]

It only died when the oil pressure dropped though.

If it is not an electrical problem, the oil pressure dropping could be a result of the engine losing RPM and stalling, not the other way around.

[erik]

Jebbysan has advised me that the oil pressure issue, coupled with the clutch rattle, could be the result of the clutch center nut not being properly tightened, allowing the clutch to "walk" off the oil pump sprocket/shaft. After starting the bike the other day, I think my electrical woes may have been caused by a poor connection at the battery as I was able to crank it up without charging the one in it. It started ok, with the exception of a knocking sound in the top end over by the (left?) clutch side exhaust cam (number 1 cylinder?) Jebbysan thinks I may have killed a cam bearing, so I may be attempting to secure a set of early cams since I will be in there anyway. Any particular year better than the other?

[daves79x]

Easy does it - one step at a time. What you were told about the clutch hub is exactly what I was speculating a few posts earlier. If you only saw the oil pressure light very briefly on, and the PO didn't run it that way long, you didn't trash any cam bearings because of that. And if you did, the head is junk as well. The crank and rod bearings suffer first in a low oil pressure situation.

I can't emphasize enough - DO NOT run this bike again until you pull some covers and check things out. Might have already gotten expensive.

Dave