Trying to figure out what this noise is

So i pick up my 1981 yamaha xj650 from where i bought it and got it home just fine. It was making some poping noises when i turned it on. So i had it for a few days riding it around when it died. I waiting 20 minutes tried turning it on again and it did. Not wanting to die on a main road i took it around a park when it died again. I left it for 8 hours ,went back to which it started fine and i was able to get it home.

Since then it wont turn over and is making a noise. So far ive put in new spark plugs, fixed an oil leak which only needed new o rings, the soleniod was making a clicking noise which a new battery fixed right up and the left turn signal just needed some solder.

The last owner said he did a carb clean and that it just needed to synched (which i have not done yet) and i noticed its running lean. I have a video of the noise and area its coming from.

Any thoughts, suggestion or advice would be awesome.

youtube

 

it sounds healthy, but make sure the battery is fully charged, or try jumping it from a car batt with the engine off.

 

Welcome to the forums!

First off, let's make one assumption: you cannot assume anything the PO did was done correctly.

Remember, when on the bike you have two small patches of rubber connecting you to the road and giving you control. If anything happens to interrupt that, your life is on the line.

So you want the bike to be able to GO, and that is the easy part. Before you can get on it and SAFELY ride it, make sure the bike will be able to STOP when you need it to. A bike that runs like a champ but can't stop when someone cuts you off doesn't save your life - it shortens it. Here are the things you need to check before you can safely ride:

Rear drum brake delamination: IF the bike has original brake shoes in the drum there is a chance they have delaminated, meaning the pads are no longer one with the shoes. This will happen all at once, probably while you are doing 50mph down the road and suddenly your rear wheel locks up on you and you no longer have full control. You can search the forums for 'Brake Delamination' and there should be a write-up on checking this.

Front brake lines: if you have rubber brake lines, check for the date codes on them. They will be a month/year date code. If your lines are dated 04/81 they are manufactured in April 1981. These lines were designed to be replaced every 4 years, so anything older than a 2008 date code should be replaced - if they rupture and fail you lose 70% of your braking - the front brakes. Also look for anywhere along your hydraulic brake system where there is a leak in brake fluid (hint: it has probably peeled paint off). These leaks need to be repaired, either by replacing brake lines or rebuilding the caliper or master cylinder. Rebuild kits are cheap and keep you alive. Order them through user Chacal or by emailing 'info @ xj4ever.com'.

Now with that noted, a carb cleaning will not guarantee a perfectly running bike. The carb cleaning is one of the LAST steps in proper engine functionality and fuel mixture. Let's start with the list, IN ORDER:

Valve clearances. Check them, make sure they are all in spec. An out of spec valve can cause tuning nightmares (that is, if you ignore / forget to do it).

Compression: Disconnect the TCI (that part is VERY important) and check your compression. If you have a low cylinder, this may indicate deeper engine demons. I believe you want to have 140psi, I'm sure someone will be along shortly to elaborate / correct my numbers here.

Clean the carbs. I know you were told it was done right, but click on the banner at the top of this page (XJ4Ever) and find 'The Church Of Clean'. That will give you the importance of properly cleaned carbs.

Clunk test / wet set fuel bowl levels. Also important, both of these ensure the engine gets the amount of fuel it needs when it needs it - both done OFF the bike. There is a write-up on XJ4Ever.com about wet setting the float levels.

Bench sync the carbs. Also done off the bike, you will need a cut piece of film (like that stuff in your old camera) and a screwdriver. If you search the forums for 'bench sync' there should be a how-to writeup on this as well.


Now once you do all that, reinstall the carbs on the bike. The bike should start and run. It will likely be a bit rough, but if you did everything so far correctly, you will have a baseline for getting started on syncing.

Test for vacuum leaks. Use an unlit propane torch and slowly go around the carbs while the bike is running. If the engine idle speed revs up at any point, you have a vacuum leak. This may be easily fixable (example: new vacuum plug caps on the intake manifolds) or it may be a deeper demon, such as worn or dry rotted throttle shaft seals.

Assuming all of this checks out, you can then do a Carbtune sync.

I know this seems like a lot to tackle, but you a member of possibly the greatest source of information relating to the motorcycle you are the proud owner of. Ask questions and search the forums and you will learn how to do just about anything to your bike that a dealership or shop would happily charge you for.

Update your profile with your location information and add your motorcycle info to your signature so we can all have important information readily available during troubleshooting and your questions. If you get stuck and we know where you live, there might be someone close by who is willing to stop in or have you stop by for a personal repair / renovation day to get your bike running in top shape.

 

xcatinthyshadowx,

Welcome and EVERYTHING Bluesbass said. Do you have a Manual yet? How many miles do you have on the speedo? Might need to check your starter motor and rotor brushes. I'd also check the Ohms on your stator and rotor. Like mtnbikecrazy said "It sounds healthy" but it's not turning over. The "clicking" sound you hear when you move your "kill switch" to the run position is suppose to happen. It lets you know that your solenoid is ready to pull and send the "large" charge from your battery to your starter motor that is needed to start your bike. Hope this helps.

Gary

 

WOW! so much to think about thanks guys. So far theres 30,000 on it and i have the hyanes (sp?) but heavily thinking about getting the original service manual.

 

Good idea.

Actually, it is turning over. It just sounds like it's not getting spark.

In addition to the above, check your fusebox, replace with blade type fusebox and fuses.

You can disconnect the safety relay to see if it's a bad safety switch somewhere in the system. I don't advise driving it that way for long though, the safeties are there for a reason.

 

Keep something in mind. Getting it to run is only a small victory in a MUCH larger process.

If you're going to properly resurrect a 30-year old bike such as these, it's going to run you between $600~$800 in parts plus a TON of work. It's very worth it; but it's not quick, easy nor cheap. (A lot cheaper than a cheesy new bike though.)

I would definitely recommend a factory book AND the Haynes; while there are mistakes in both, the ones in the Haynes are BIG and ones in the factory book, minor.