1st post and some questions

[BillyRok]

Hello Everyone - I discovered this site about a year ago and followed the conversations for a while before joining...been reading and learning a ton since the start...quite a resource of knowledge and experience you've all put together here in one place. In fact this site is a big reason I bought an '82 XJ last July after deciding to start riding again ('82 Kaw KZ750 was my only other bike). It had 32K on it and was in good running condition...here are some pics (I hope?!)





http://i1249.photobucket.com/albums/...2XJ1100003.jpg

I put a couple thousand miles on it last year but want to do some work on it before the season starts again here in upstate NY (snowed today ) Got a new fuse block from T.C. and YICS Eliminator from Yahman (thanks men) and sprung for a new service manual.

First I checked the compression and got readings of 125, 125, 125, and 130...the book says 142 lbs so I guess I'm good there. Then I pulled the valve cover to check valve clearances, here's what I got:
Intake #1-4: all read .005 in. Exhaust #1-3 read .009 in and #4 reads .008 in.
So everything is in spec with #4 exhaust at low end, so I'm good right?
But here's where I hope somebody can enlighten me. If you measure clearance between the shim and cam heel, since the heel never contacts anything (no wear on heel), the clearance gets tighter as the valve gets recessed into the head with wear? And too little clearance means the valve doesn't open all the way leading to burned valves? If this is all true, what I wonder about is where does wear on the cam lobe factor in? If all my clearances are in spec couldn't I still potentially have problems if the cams are worn so the valves still don't open properly? Is this a silly question? I appreciate the input. Any other tips/suggestions are welcomed as well!

Again, you've got a great forum here. I'm looking forward to learning more about these great bikes and meeting some new people.

Thanks - Billy

[JasonRedbeard]

First off, welcome to the board.

About valvetrain wear: valve clearance does tend to get tighter over time, as the valves and seats wear. However, excessive valve wear doesn't mean the valves don't open enough...it means they won't close fully. If you don't have any valve clearance the valve won't close against the seat because the heel of the cam will still hold it ever-so-slightly open. This is why it NEEDS some clearance...to be sure the valves will close fully through the full range of thermal expansion that the engine sees.

As far as cam lobe wear goes: keep your oil changed and you'll never see enough to make a difference.

[motoman]

Decent lookin XJ!..................someone even swapped out the stock exhaust for the unobtanium Jardine 4into2's/ spagetti head-pipes.........sweet!

[fredintoon]

Hi Billy and welcome,
valve train wear happens like this:-
Over time the cams & shims wear to give more valve clearance.
At the same time the valves pound deeper into their seats to give less.
With the XS11's DOHC shim & bucket valve mechanism, the valves pocket deeper into their seats quicker
than the cams & shims wear away so the valve clearances get less over time.
Finally the valves have so little clearance that they stay a little bit open when they should be fully closed.
That's when the exhaust gases start to act like a cutting torch to burn the valves out.
Guess what? There's no place to buy new valves.

[ddragon63]

It looks as everyone has explained how the seats and shims wear to make tighter clearances thru the years... and the importance of the valve closing. I will try and explain to you now the reason why you measure your clearance @ the heal of the cam.

The heal is the most distance between the cam and its contact surface... you measure clearance here because all the cam timing is based upon this small area. if the clearance is tight the cam will have more duration and overall lift, if too loose the the cam will have shorter duration and lift. Cam timing is very important for many reason I could type about for hours.... but most important its designed for a specific timing to ensure that the follow don't happen... if the valve is open too long on the intake side you can lose intake draw as the exhaust valve opens... and if the valve closes too soon you can cut the full draw off too short... obviously if the exhaust valve opens too soon it will contaminate the intake draw... if it closes too soon it wont fully scavenge the cylinder of waste and contaminate the next intake draw... and if there is NO clearance the valve will never fully seat and all is lost

all valve clearance on all motors is determined from the heal of the cam that is how they grind the cam... that's why even on a hydraulic V8 cam you set each valve when the cam is on the heal side. 1/2 turn from static is roughly .100 into the plunger of a non oil loaded hydraulic lifter wich is the "factory" equivalent of .000 when pumped up with oil upon fire. this is why the starting side of the lobe of a Hyd cam is a VERY gradual climb and on paper a Hyd cam will always have more duration @ .001 than a solid cam even thou they share the same duration @ .050... because the hyd cam has to climb from 0 and keep the valve closed for the time as allotted by the heal as where the solid cam has a set heal clearance and once contact is made it can go ahead and set the valve on its course...

This is why all Hi performance engines run a solid "mechanical" lifter (most motorcycles run solid lifters) where there is a set heal clearance. therefore the cam grinder can profile the cam for best volumetric efficiency. based on "At this given point the clearance WILL BE THIS!"

now that we are cam smarter I think I forgot how to spell my middle name
that was long winded but I hope it helps other to understand how a cam works

[Schming]

Nice XJ

Hello Everyone - I discovered this site about a year ago and followed the conversations for a while before joining...been reading and learning a ton since the start...quite a resource of knowledge and experience you've all put together here in one place. In fact this site is a big reason I bought an '82 XJ last July after deciding to start riding again ('82 Kaw KZ750 was my only other bike). It had 32K on it and was in good running condition...here are some pics (I hope?!)





http://i1249.photobucket.com/albums/...2XJ1100003.jpg

I put a couple thousand miles on it last year but want to do some work on it before the season starts again here in upstate NY (snowed today ) Got a new fuse block from T.C. and YICS Eliminator from Yahman (thanks men) and sprung for a new service manual.

First I checked the compression and got readings of 125, 125, 125, and 130...the book says 142 lbs so I guess I'm good there. Then I pulled the valve cover to check valve clearances, here's what I got:
Intake #1-4: all read .005 in. Exhaust #1-3 read .009 in and #4 reads .008 in.
So everything is in spec with #4 exhaust at low end, so I'm good right?
But here's where I hope somebody can enlighten me. If you measure clearance between the shim and cam heel, since the heel never contacts anything (no wear on heel), the clearance gets tighter as the valve gets recessed into the head with wear? And too little clearance means the valve doesn't open all the way leading to burned valves? If this is all true, what I wonder about is where does wear on the cam lobe factor in? If all my clearances are in spec couldn't I still potentially have problems if the cams are worn so the valves still don't open properly? Is this a silly question? I appreciate the input. Any other tips/suggestions are welcomed as well!

Again, you've got a great forum here. I'm looking forward to learning more about these great bikes and meeting some new people.

Thanks - Billy

Looks like the upper posts took care of the cam and clearance facts for ya the only thing I can suggest is "Set 'em and forget 'em" and in the off season about a 10,000 mi. interval You may want to check the clearances again. Now the cam chain adjustment done at 3000 mi. intervals, when a usual oil change is done, will keep the top end running smoothly.
These engines are bullet proof with a little maintainence.

Have you gone over your braking system?
Have you changed your middle drive and final drive oils?
Have you pulled the final drive to lube the driveshaft splines as the grease zerk on the swing arm is poorly located and won't get the grease where it needs to be?

You may want to check out XJBikes.com , look up Chacal for parts.

[fredintoon]

It looks as everyone has explained how the seats and shims wear to make tighter clearances thru the years... and the importance of the valve closing. I will try and explain to you now the reason why you measure your clearance @ the heal of the cam. - - -

Hi Don,
thanks for the expanded explanation.
Spoiler alert, the following will reveal that despite my denial just perhaps I am a curmudgeon after all
Why don't you fellows learn to spell?
BREAK is what the loan shark's enforcers do to your legs when you don't pay.
A BRAKE is a device that slows your bike down.
HEAL is what you hope your legs will do.
A HEEL, besides being the thing on the back of your foot, is part of a cam's surface.
Thanks.

[BA80]

Hi Don,
thanks for the expanded explanation.
Spoiler alert, the following will reveal that despite my denial just perhaps I am a curmudgeon after all
Why don't you fellows learn to spell?
BREAK is what the loan shark's enforcers do to your legs when you don't pay.
A BRAKE is a device that slows your bike down.
HEAL is what you hope your legs will do.
A HEEL, besides being the thing on the back of your foot, is part of a cam's surface.
Thanks.

Thanks for the spelling lesson Fred

[ddragon63]

Hi Don,
thanks for the expanded explanation.
Spoiler alert, the following will reveal that despite my denial just perhaps I am a curmudgeon after all
Why don't you fellows learn to spell?
BREAK is what the loan shark's enforcers do to your legs when you don't pay.
A BRAKE is a device that slows your bike down.
HEAL is what you hope your legs will do.
A HEEL, besides being the thing on the back of your foot, is part of a cam's surface.
Thanks.

Meh.... as long as i can spell my name right on the deposit slip when I put my pay check in the bank I'm not too worried about the rest

[ddragon63]

Hi Don,
thanks for the expanded explanation.
Spoiler alert, the following will reveal that despite my denial just perhaps I am a curmudgeon after all
Why don't you fellows learn to spell?
BREAK is what the loan shark's enforcers do to your legs when you don't pay.
A BRAKE is a device that slows your bike down.
HEAL is what you hope your legs will do.
A HEEL, besides being the thing on the back of your foot, is part of a cam's surface.
Thanks.

Hopefully I spelled all your info correctly on the shipment of lights I sent you.... Ball buster!

[ddragon63]

Looks like the upper posts took care of the cam and clearance facts for ya the only thing I can suggest is "Set 'em and forget 'em" and in the off season about a 10,000 mi. interval You may want to check the clearances again. Now the cam chain adjustment done at 3000 mi. intervals, when a usual oil change is done, will keep the top end running smoothly.
These engines are bullet proof with a little maintainence.

Have you gone over your braking system?
Have you changed your middle drive and final drive oils?
Have you pulled the final drive to lube the driveshaft splines as the grease zerk on the swing arm is poorly located and won't get the grease where it needs to be?

You may want to check out XJBikes.com , look up Chacal for parts.

+1 While the oil is draining out of the pan it takes about 2 minutes to adjust the CCT. gives a Fella something to do while waiting. I'm still thinking of possibly putting an auto CCT on mine but that's a can of worms to be opened @ a different time.....

[motoman]

I'm still thinking of possibly putting an auto CCT on mine but that's a can of worms to be opened @ a different time.....

That can of worms may open itself if you think about it TOO long........just sayin'.....

[Poprock]

Obtain one. Pull old one off. Clean mating surfaces. coat liberally with Yamabond 5. Put a gasket on...or not. Be sure to shorten the bolts a little bit. The Venture cam tensioner is a little thinner than the XS-XJ one. Button her up and never look back.

[James England]

If your OEM tensioner allows the chain to jump a tooth, you'll have several cansful to keep you going

[XS1100_OEM4ME]

Chill

Hi Billy, and welcome. From what I read, you are all good, so CHILL and ride that sweat bike

Hello Everyone - I discovered this site about a year ago and followed the conversations for a while before joining...been reading and learning a ton since the start...quite a resource of knowledge and experience you've all put together here in one place. In fact this site is a big reason I bought an '82 XJ last July after deciding to start riding again ('82 Kaw KZ750 was my only other bike). It had 32K on it and was in good running condition...here are some pics (I hope?!)





http://i1249.photobucket.com/albums/...2XJ1100003.jpg

I put a couple thousand miles on it last year but want to do some work on it before the season starts again here in upstate NY (snowed today ) Got a new fuse block from T.C. and YICS Eliminator from Yahman (thanks men) and sprung for a new service manual.

First I checked the compression and got readings of 125, 125, 125, and 130...the book says 142 lbs so I guess I'm good there. Then I pulled the valve cover to check valve clearances, here's what I got:
Intake #1-4: all read .005 in. Exhaust #1-3 read .009 in and #4 reads .008 in.
So everything is in spec with #4 exhaust at low end, so I'm good right?
But here's where I hope somebody can enlighten me. If you measure clearance between the shim and cam heel, since the heel never contacts anything (no wear on heel), the clearance gets tighter as the valve gets recessed into the head with wear? And too little clearance means the valve doesn't open all the way leading to burned valves? If this is all true, what I wonder about is where does wear on the cam lobe factor in? If all my clearances are in spec couldn't I still potentially have problems if the cams are worn so the valves still don't open properly? Is this a silly question? I appreciate the input. Any other tips/suggestions are welcomed as well!

Again, you've got a great forum here. I'm looking forward to learning more about these great bikes and meeting some new people.

Thanks - Billy