XJ550 SECA Engine Noise

Went on my first 10 mile ride on my XJ550 today. This was the first time I have had it on the road and got to beat on it. First thing, is its making a thumping sound at idle. Can't be the bearings, since I don't notice it when not at idle. I figure an exhaust leak. You can hear it in the video. Also getting some other intermittent noises when accelerating. Not all the time though. I got on it pretty good a few times in the 7000 to 8000 rpm and it sounded pretty good. Other times I get a high pitch sound. I'm hoping it is something simple like the tachometer or its cable. You can hear one sound in the video at the 3.08 second mark. Any guess out there? My camera was running out of batteries. I will try to post a better video tomrrow.

XJ550R Noise - Click Here

 

Re: XJ550 SECA Engine Noice

yeah not sure about sound judging from the video. you should get like a plastic lawn marking flag or your hand and actually feel around the areas you suspect a leak and see if you can get the flag to move or feel something on your hand.

on your xj. im pretty sure there are two small holes. one near each silencer muffler deal. other than those holes and the two exhaust ends, you shouldn't get any air coming from anywhere else.

 

There is a bunch of extra noise in the video but it sounds like you have an exhaust leak to me.

 

The "thumping" sound at idle is a characteristic of the 550/600 motors due to the hydraulically tensioned "true" primary chain. In those motors, the primary chain actually drives the transmission, and as such it has an oil-pressure operated chain tensioner (as opposed to the shafties. Their "primary" chain only connects the alternator and starter to the motor, primary drive is by gear.)

So when a 550 is idling, with lowered oil pressure, the primary chain goes slack and will "thump" or "knock." What's actually happening is it's shaking the trans guts and clutch and magnifying the sound.

This particular sound can be greatly reduced by getting the bike properly tuned and smoothing out the idle; and by making sure you run the correct oil.

That being said, you have worse noises going on. It sounds like the cam chain is horribly loose, and it also sounds like the motor is only running on about 3 1/2 cylinders.

Have you adjusted the cam chain, checked the valve clearances, done any of the important maintenance items? A compression test? What oil is in it?

Quite honestly, that's one unhappy motor. When you take the valve cover off to check the valves, pay close attention to the front cam chain guide. It sounds like it might be out of place. It does also sound like there might be an exhaust leak; but honestly I wouldn't ride the bike with that motor sounding the way it does.

 

that took a lot of cranking to fire up

 

Yeah it did.

 

Yeah, haven't done anything to the engine yet. Thanks for the information regarding the primary chain noise and cam chain guide. Will certainly investigate it. So far I have only rebuilt the M/C and caliper. Unfortunately, I have spent all of my parts fund for this quarter on a new original fairing. Here is a list of things l still have to do before I can use it as a daily rider:

1. Change oil and filter (filter should have be in yesterday).
2. Once money is available, inspect/adjust valve lash (need gaskets).
3. Adjust the cam chain tension.
4. Do compression test.
5. Drain old fuel in the tank and clean out any debris (if any). Confirm vacuum petcock is funtioning properly.
6. Inspect and replace front fork fluid.
7. Colortune the carburetors.
8. Sync the carburetors. I have a Morgan Carbtune for this.
9. Change the rear break shoes (already have the new shoes).
10. For now, inspect the rear bearings when the wheel is off to do the
brakes. Grease if needed (unless the are the sealed type)
11. Check for exhaust leak.

I have another set of carbs I will be cleaning at the same time. So that will be ready as well.


I will post a better video with better sound this weekend. Thanks for the help.

I must say, the bike is so much different than my KZ. It felt like a scooter in comparison with regards to weight, LOL. It feels more refined as well. The handling is worlds better. The power delivery is completely different and very smooth. Comes on strong starting at the 7000 rpm range. I can only imagine how much better it will be once its tuned. I'm psyched!!!

 

I wasn't kidding. Don't keep riding it like it is or you're gonna kill it.

#3 needs to become #2 or immediately. It's BAD loud. NOT good.

#2: park it until you do. It's not running on all 4.

#4: wait until the valves are in spec lest you freak yourself out.

#7 is LAST; you don't ColorTune until it's in sync; then the two go hand in hand. The carbs need to be serviced first; and their float levels meticulously wet-set. The Morgan won't help if you have wonky float levels. Mikunis are fussy. (ask a man with two 550s-- oh, wait...)

#10: is impossible without removing the bearings. The originals are sealed on ONE side; the side you can't get to. Removing them will damage them. Just replace them; or leave them alone. You should be more concerned about the chain and sprockets.

Rear wheel bearing how-to: http://xjbikes.com/Forums/viewtopic/t=35134.html

But you seriously have to attend to the motor before it gets badly hurt.

 

Oh, and I'm sorry you sunk all your funds into that silly fairing. It clobbers the handling and slows the bike down. Yamaha did away with it for the '83 model year; and I did away with it on my '81 as well.

Once the bike is running right, ride it both with and without the fairing. You'll understand.

 

No worries, won't be starting it up again until I sort these things out for sure. I had planned on pretty much following the sequence I jotted down. Step 2 valve adjustment and 3 tensioner adjustment will be done at the same time. I was a bit surprised to learn the bike has a manual tensioner. Figured that it would be an automatic one for an 80's bike. But of course, even an automatic tensioner can fail and needs maintenance. I do like the manual ones better. The compression numbers from step 4 will determine what happens from that point on. Assuming the compression is O.K., I can move forward.
Totally agree about the rear bearings. Although I'm pretty confident I can take them out without damaging them. I generally use my torch to help ease the removal and installation of the wheel bearings and they come out with about the same amount of required effort as the do going back on. But I guess for the 30 bucks for a set of new All-balls bearings, I should just replace them now.
Fitz, I'm not sure if this is correct or not, but my other service manuals (other make) pretty much state that the fuel / air mixture is to be adjusted first before syncing. For the XJ, the PDF service manual I have is specific to the 81 XJ550RH and doesn't even go into the setting of the pilot circuit mixture. Only has a statement about it being factory set. I guess due to emission laws of the day. Now you have me wondering. I may send a query to Morgan Carbtune Ltd to get their opinion. I think it is important. Although, I feel the times I have synced my other bike it has worked out great.
Oh, and as for the fairing, LOL, I have read your concerns about it in other threads. I have two SECA's, an '81 and an '82. I want to restore the '81 to as close as possible to the bike below. More for sentimental reasons. This is a picture of my roommate's SECA after he wrecked it taken in '82. It was a gorgeous bike up to that point. The only thing I see that won't be able to find is the Yoshimura 4 to 1 exhaust. That bike had one of the sweetest sounds that I can remember.



Click Here For Larger Image

 

Call Yoshimura. If you have the money they will make you that same exhaust (they used to take requests anyway).

 

Your "RH" manual IS the only FSM for the 550s. And yes, they refuse to acknowledge the existence of any adjustability to the pilot screws.

Mixture tuning comes after the vacuum sync; although you may need to go back and touch it up after adjusting mixtures. But to get your initial vac sync, set all the pilots at 2 3/4 ~3 turns out to start. Vac sync; then tweak mixtures. Then go back and touch up the sync. Lather, rinse, repeat as needed to get it idling as smooth as a sewing machine. It's possible to completely eliminate the "lump, lump, lump" from the idle but it takes some doing.

That being said, having a Morgan CarbTune and a ColorTune makes it much easier to achieve. Just be sure to properly block YICS for the sync and mixture adjusting.

Rear wheel bearings get "killed" in the removal process because there is no way to get at the outer race to tap it out, you end up having to beat on the inner and then the bearing is compromised.

 

I am reviving this thread in hopes it will help others. Thanks to help from a fellow member specialk, I have recently solved and fixed a noise that appeared at 4000 rpm. You can hear the metalic noise at the three minute and eight seconds mark of the video. The cause turned out ot be the sheild that is attached below the carburetors covering the float bowls. By wedging some rubber fuel hose in a couple places between the shield and the float bowls, I was able to surpress the noise. Makes for a much more enjoyble ride.

 

Funny thing is when the noise first occurred on my bike it was right after spanking on it at the drag strip, I thought to myself "well thats it I've finally killed it, time to stuff in the 600cc motor." But no! Just an annoying heat shield.

 

You can see how long I have been chasing the noise. About 2 1/2 years. Granted, I didn't ride this bike because of it. Maybe about a 1000 miles. Used a harbor fright stethoscope a couple of times in search of it. Inspected tank for contact with the frame, speedo cable and tach cable. Followed by the clutch, charging system components and complete exhaust system. Of course, all of these components checked out. How did you track it down?

 

I noticed it was loudest at a certain rpm which made me think it wasn't something mechanical as I would assume it'd get louder as rpms increase if that were the case. I was riding one day and held the rpms constant at the speed the sound was the loudest. I placed my hand on the heat shield and that stopped it completely so I figured it out that way, just lucky I guess.