1973 Yamaha XS650 engine noise

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kimoaj

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Hi guys!
This is my first post on this forum, I`m a 26years old guy from Norway. A few days ago I got my 1973 XS650, bought it unseen and got it shipped from Oslo to the North of Norway.
I love the looks of the bike, the sound, size, handling, all in all a great bike. My previous bike was a 2003 Kawasaki Z1000 so this vintage stuff is all new to me.

I am having some concerns about some engine noises. I`ve read that the XS engine makes alot of noises but I wonter how much is normal?

It is hard to describe a sound especially when you write in a foreign languagem but I think it sounds like "clank clank clank clank clank".

I hope it`s just a valve that is too loose, today I changed the oil on the bike and while I was at it removed the left side exhaust valve-adjustment cover. Measured the clearance to 0.30 (hot engine). As soon as I get the chance I will remove all covers and adjust all valves when the engine is cold.
From what I could read on the internet the clearance should be 0.15mm for the inlet valves and 0.30 for the exhaust valves, is this correct?
One thing I notised was that the rocker arm was hitting the valve in the center of the valve, is this normal?

Could the sound have anything to do with the camchain being to loose or wornout/wornout guides?

Or can it be a bad rod big end bearing? (really hope not!!)

I dont know the milage of the motor cause the bike has been rebuilt and customised with a speedometer from another bike so.. .
I will try make a recording of the sound and post it here.

Any opinions will be greatly appreciated!

Thanks
Joakim
 
I just did a recording with my photocamera:

Although I must say that it actually sounds even worse on the recording, it is not that noticable in real life.
Any opinions?
 
It sounds normal to me, or I should say it sounds like other recordings of normal engines on Youtube :)

In the last seconds I hear a higher tone peck, but I still don't think it's out of the realm of normal. See what's going on under the timing covers.

I think all the noises are too high in tone to be the bottom end. Also, it doesn't sound like a loose cam chain. I would adjust the valves and then go from there. I don't know the gap for your year engine. For an '81 it's .003" and .006"


But check the cam chain too, and before the valves. Unfortunately the engine will warm up while you do the chain, and the valves should be done cold, so it might take two days....
 
That sounds like loose valves to me. Set them @ .075mm (.003") intake and .15mm (.006") exhaust. The .15 and .30 spec was only for the 1st model year, the 1970 XS1. Yamaha reduced them after that, probably due to all the racket they made, lol.
 
Hei, ikke veldig mange norske her? Veldig bra forum, det eneste leie er at jeg føler meg veldig amatør i slikt selskap.....
Min 1975 lager litt lyd den også, bør sikkert sjekke/justere camkjede og deretter ventilene.
 
Hi guys!
Thanks so much for the replies, I really appreciate it! :) I would like to comment each reply but it is very time consuming.

I will adjust the camchain and then adjust the valves.
There are alot of writeups on how to do both this and that but I like to ask myself so that I know the methods are correct for my year of bike etc. (I also wonder what changes have been made on these engines since start to end of production?)
So how do I tighten the camchain correctly?

As for the valves I am alittle confused about the clearances.
From the little reading I have done it seems like you have to set the valves somewhat too tight to avoid the ugly sounds?

I havent checked my valves yet but I figure I am running the .006" - 012" , (0.15mm intake and 0.30 exhaust)
Can I really readjust to 0.75mm on the intake and 0.15mm on the exhaust?

I dont want to burn a valve!

I also really wonder what oil to run on the bike? I put Yamalube mineral 10W40 on it, is that okay?

I`m very happy with the looks of the bike, it is converted from dual shocks in the rear to a mono shock, it looks like they have done a real good job.
I dont know what bike the front end comes from, will try to get in touch with the owner to get some more history on it. (his father arranged the sale cause the owner has moved to another country). I am missing the left side sidepanel but a new one is on its way.

They have fitted cone style airfilters on it and I figure it would be a smart move to put some prefilters on them to avoid water entering them cause they arent that protected from the surroundings.

Thanks again for the replies!

Stigda: I dont know how many Norwegians are in here but probably more then we think:) Where in Norway do you live?
 
Hi there, Bergen and then of course a lot of rain. Dont think I'll try the pod filters, then again I only ride in goo weather.

Stigda
 
On the 75 and 81 I have I set the valves to .003 I, .006 E. They both run well with just a slight noise.
I like to adjust the cam chain with the engine warmed up, at idle. Remove the cap, look to see that the plunger is moving in/out about 1-2 mm. As the plunger moves in/out adjust so it just comes flush on the out part of the movement.
If you get it too tight the plunger stops moving. If too loose it moves more than the 1-2mm.
Leo
 
that's a great bike! You can take a long screwdriver and hold the handle end up to your ear and touch the bit to different locations on the running motor, and the sound will be conducted quite well to your ear. Try it! Be careful of the vibration however! Beautiful bike well worth investing a little time and money in.
 
Hey Joakim, did you find out the problem with that noise? That is a good looking bike. Hope it is out on the road.
 
How often do you guys find yourselves readjusting the valves? After hard running, I have to adjust mine again back within spec probably within 400miles cause of all the tappity-tap-taping going on inside the rocker box.
 
I check mine at about 2000 to 2500 miles, every other oil change.
Checking at 400 miles is ok, but if they need adjusting at that point then I think you have something wearing too fast.
Hold on, how long have you been running this engine?
If you just got it running after a long sleep then it might need adjustments more often, but should get better after a couple thousand.
Leo
 
This bike is my daily driver. I've had two different cylinder heads in the engine (stock and then one ported with elephant feet adjusters) with the only common denominator being the cam. The valves seem to get loud after a couple hard runs or after a weekend of cruising on the freeway. I checked the oil pump and the screens and they looked fine.
 
I had one ...believe it was the left exhaust, that would loosen up after a bit. Last time I adjusted it I tightened the dog crap out of it. Been about 2 grand and she's still quiet.
 
i've got 22xxxx miles on the original tensioner (not the front cam guide), but how long will the rear cam chain tensioner last? I have a dense clank going on that seems to get worse with climbing rpms and it persists even after setting the cam chain tension (to the best of my ability) and the valve lash..... what else could it be?
 
Also check your oil see if there are any black plastic pieces if there are then the plastic from the cam chain guide is coming off, thats what it sounds like to me. Check your sump filter as well for little black plastic pieces. Good luck!
 

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