Motorcycle issues! Any advice? (long/extensive/detailed)?

Question

Thank you in advance for taking the time to read this, ive included a lot of detail, some may not be permanent, but bear with me!? :) Any responses will be appreciated!

Bike: 78 cb550k sohc 4 stroke/4 cylinder with 36k miles. its recent changes: Carbs cleaned and synched, valves adjusted, OEM rectifier, stock rust free gas tank, fuel filter, newly rewound stator, new yuasa battery.

1. My throttle seems to get stuck, or is forced to be constantly turned about a quarter of an inch in rotation counterclockwise from the right profile of the handlebars. I am usually have to twist the throttle a quarter inch clockwise when I come to a complete stop to reduce the rpms from 3000 to 1000 while idling. Having thought it may be a valve getting stuck ive tried revving the engine holding the clutch to see if the throttle goes all the way back on its own, but it doesn't. Do I need to tighten the throttle cable to pull the throttle all the way back to the expected/standard stationary position?

2. Im rarely able to get the bike into neutral when the bike is running. It slips past neutral, always going into first or second gear, until i kill the engine and it goes to neutral easily(kill switch or key while holding clutch in when i turn it off).

The clutch also slips often when riding, especially from first to second gear. The clutch usually doesnt grab first gear until its almost completely extended as well, which makes it frustratingly easy to release the clutch too far. The bike also jumps forward abruptly if the friction zone isnt handled gently when going into first from a stop. How can i adjust the friction zone? Ive been told it could be my clutch cable, or someone has said most likely the gear itself that has been worn down/dulled.

3. Squeaking coming from the front fork, which i can see the seals are leaking and have been leaking. The fork now squeaks over bumps and whatnot. Is there an easy way to supply more fuel? I dont have the tools to fix the fork seals. Id like to avoid paying a mechanic because ive heard it is possible to do yourself.

4. Final issue that worries me the most is that the engine becomes louder in any gear above 4000 rpms in a way that sounds similar to rattling or clanking. It usually only happens after ive been riding for an hour or so - sometimes continuing to make the sound even in lower rpms, just not as loud. But it is a distinct sound that occurs only after an 30 min to an hour of riding. I do live in arizona, where it is over 100 degrees during the day. The sound is less common at night.


What baffles me is that when I have taken the bike to a mechanic they tell me the bike has a great strong engine.

~Thanks~

Answer 1

Throttle response, Honda's of that period used 2 cables counter twisting the throttles , replace both cables and the clutch. The neutral problem is really a NO PROBLEM there is no detent or grabbing point for neutral it is is just a spot between 1 &2, the slip is an adjustment issue, but since your cables are thirty years old and has been adjusted causing lots of kinks you're better off replacing the cables.

The fork seals just as old, and can be replaced with a manual and an Ice pick.

Answer 2

Ahhh...the beauty of a 30 year old bike!



I too own a 78 550k, a 75 550f and an 02 Harley SuperGlide. That aside...



1) Throttle cables need adjustment and return spring may be shot.



2) Adjust clutch cable or clutch needs replacement.



3) You could try using a heavier weight fork oil but I think that'll only provide a temporary solution. In the long run, it may make the seals worse. You should probably just bite the bullet and replace them.



4) Hmmm, this one puzzles me a bit. Perhaps your oil pick up tube is restricted and not able to pump enough oil to the top end. Valve adjustment (oops, you already did that, maybe done incorrectly or loosened) or timing chain could be another cause. What weight oil are you running? I suppose if you're running 10-40, in your heat you could go to 20-50 without too much problem. But again, the heavier weight oil is going to put greater stress on gaskets and seals. Particularly those that may already be compromised.



The engine can still be considered "strong" yet still have the symptoms/problems you've described.



Try www.sohc4.com. Its a forum for bikes like ours.



Good Luck!



EDIT: Enjoy the sohc forum.



I guess some HD basher gave me a thumbs down for owning a Harley. Oh well. Or they're just jealous I own 3 bikes. To add to the jealousy factor, I also own a 2009 Pontiac G8 GT (rockin muscle car!) and a 2000 Toyota 4Runner SR5 to take me to the mountains to ski in the winter. Next year I'm adding a Cobalt 240 to the stable. One guy, five (soon to be six) vehicles.



Life is good!

Answer 3

Older bikes like this often have 'idiosyncrasies' that you can't get rid of now matter how hard you try. I have a 78 BMW that's getting crotchety in its old age. 8^) But then so am I.



The throttle problem could be the cable is too loose. It could be the return spring is stretched and no longer pulling the cable back to 'home' position. Check it out, look at the spring and you can probably see.



The clutch problem sounds like a cable adjustment too. Sounds like the clutch is not closing all the way or opening all the way. You might need a new clutch.



Fork seals are a common problem with old Hondas. I'm pretty sure you can still get the seals. Replacing them is something you can do yourself. It's a pain in the neck, but you will learn a lot about the forks in the process. If you don't replace them, you'll wear out the surfaces, and then even new seals won't help.



The last issue sounds to me like valves need adjusting. But you say that's already done, so it can't be that. It might be the cam chain, either the tension needs to be adjusted (easy to do) or it needs to be replaces (not so easy, but still doable).



My Beemer makes lots of intermittent rattling/clanking noises. But my mechanic says nothing is wrong, and it's been making those noises for about 30k miles now. So I wear a pair of foam earplugs and I don't hear them. 8^)

Answer 4

1. Lubricate your throttle cable and return spring (if any). If this doesn't solve the problem, get a new cable.

2. Adjust your clutch cable properly. If it still acts up, replace your clutch plates.

3. Replace your fork seals and fill with the correct amount of fluid.

4. Drain your oil. Remove your oil filter and run the bike, pumping the old oil left in the engine out the filter line while pouring fresh oil into the oil tank. Once the fluid coming out of the motor comes out clear, shut the bike off, put on a new filter, and fill to specs with straight 50 or 60 weight oil from a bike shop. Your oil is thinning out in the AZ heat and losing viscosity. Change it like this religiously every 3k miles.

Answer 5

Not with a regular car plug from the outside. Patch/plug from the inside. From the Dunlop website FAQ: Some punctures in motorcycle tires can be repaired if no other damage is present. Dunlop recommends only individual permanent plug-patch repairs of small tread area punctures from within the demounted tire by a qualified tire repair shop or motorcycle dealer. Never perform an exterior repair and never use an innertube as a substitute for a proper repair. Your bike should not exceed 50 mph for the first 24 hours after the repair and the repaired tire should never be used over 80 mph. Dunlop speed ratings are voided by repairs.

Answer 6

lots of good advice....



have a look here.. M/C mechanic online.. tells you how to do lots of stuff on your bike.. including fork seals..



http://www.dansmc.com/MC_repaircourse.htm





& you can get a manual for free here.. download from honda..



http://hondatech.info/downloads/Moto/