shimming valves...

I just came back in from checking my valve clearances. It looked to be an extensive project and I figured I'd be in the shop for the remainder of the day, but, they are all in specs!! The valves haven't wore a bit. It could be the fact that I use synthetic oil?
The dealer next door (motorcross and snowmobile dealer) has the tool, but I didn't even have to go get it. Now after the paint dries on my valve cover, it can go back on.
The gasket I won off Ebay Monday, came today by UPS, so things are looking up! After the paint dries on the valve cover, I can put things back together. PD

 

thats okay i cast a hardening spell on them :lol: just kidding. hopefully it doesn't matter too much because thats what i was told to do by a veteran yamaha race car builder... (yes i do realize i said yamaha and car in the same sentence.) we'll see how it ends up and i'll let you guys know

 

I know this will make RickCoMatic and possibly a few others shudder,but I have knocked a touch off valve stems rather then trying to lap down the shims

 

as long as your willing to accept the consequences do whatever you want.

 

Yamaha race car??? Tell us more!

 

actually there is no consequenses if you know what your doing and have correct tools, valve stems should be touched up when grinding valves to resquare and eliminate any pitting and scoring

 

perhaps i gave the wrong impression... its a yamaha powered race car it has the engine from a mid-eighties FJ1200 similar in many ways to the XJ bikes just bigger mostly.

they're generally called 'legend cars'

http://www.circletrackracingnews.com/wp ... stom-2.jpg

they're a bastardized yamaha motorcycle, toyata car, and 30's ford.... pretty lame if you ask me but it was always fun to work on them with him. now he's moved up a bit (or gotten more money ) and he's racing an A/C cobra

you can see a dumb video of it here

http://www.youtube.com/watch?v=7YjyGqcxitc

 

"Can't be done!" I love when people tell me that. It just makes me prove the wrong. Some just think because the book says that's the way, isn't always the ONLY way. PD

 

I am about to tear in to the valve cover myself and check/adjust clearances. I've never done that but I have studied up on it, and understand it. I ordered feeler gauges on ebay. Im still looking for a valve shim tool (Chacal PM me a quote if you have one) and I know Im going to need a new cover gasket. Also where is the best place to get shims?

 

Some have stated that Yamaha dealers might have them discs and will just exchange the new size ones for yours. I was fortunate enough not to need any, so I don't know if they do here or not. The tool would come in handy. I was about to make my own untill I found out I didn't need one this time, but I will need to get (or make) one eventually.

 

Energi2er....you got mail!

 

hummm i always like checking and ajusting valves always makes me feel closer to my bike.

 

This is a project I will soon tear into as well and am dreading. I have a manual on cd, can't remember which one. I hope it tells me and I understand but I wouldn't know what my goal even is. I mean with the shims and clearance and what not. I have no idea what ideal or out to lunch looks like. But I'll guess I'll find out.

Also I need to take off the head as I'm certain that I have a leaking head gasket. That brings more worries with the timing chain and what have you. But I'll save that for another thread coming soon.

 

hmmm i wouldn't fret the valve shimming... i made it sound alot worse than it was but it was the single most beneficial thing i've done for my bike so far... so the moral of the story is GO OUT AND DO IT! 'just take your time and you'll be sitting pretty. it also helps to have a micrometer but you absolutely must have a set of feeler gauges.

 

I'm 'bout to do mine on the Maxim, just have to figure out a way to get the shims out. Like a dumba$$ I measured the clearance but didn't plan far enough ahead to be able to take out the shims and measure them. As the clearances turned out, about half my valves are out of spec on the tight side. It seems my valve seats wore faster than my shim/cam did. Ahh, a fun job for spring.

As far as grinding on the shim, I would be less concerned with grinding off the case hardening and more concerned with making sure the shim is ground flat, i.e., both sides are parallel to each other. Think about it--if you grind a taper into your shim, one end of the lobe or the other will take all that load and possibly lead to premature wear. You'd have a corner/edge of the cam lobe bearing down on the face of the shim, rather than the whole face of the cam lobe.

This is assuming, of course, that the ground side goes DOWN (into the bucket) and does not face the cam. The hardness is there to reduce wear between the cam lobe and the shim. Case hardening doesn't do much of anything between the shim and the bucket.

I just realized I'm assuming the bucket/shim setup here is the same as it was on my Fiat, so maybe the Yamahas are different. But I'll just assume they're the same until I get in there and/or read the manual more closely :wink:

 

if your careful, and have a micrometer lol, you can make sure that your pretty dang close to flat. i did mine using a magnet and the side of a grinding wheel and i just went really slow and let the shim spin on the magnet as the wheel took off tiny bits at a time and after checked it with the mic' and they're perfect.... i'm not worrying about it. and yes i did face the ground side down.

 

Guys! You know that replacement shims aren't very expensive, $ 7.50 each or less in sets of 5.........between being able to swap around some shims and the typical wear patterns, it's unlikely that any engine will need more than 5 new-sized shims.....why take the risk of re-grinding old shims, and either messing things up or causing more wear and more future valve adjustments in the future?

 

your right chacal and if i do it again i'll probably order them from you but i like the sense of accomplishment i get from doing it myself... i'm sure you can appreciate that

 

Men:

You don't grind shims!
You get the right Shim and install it without trying to machine anything.

If you dont have the Shim tool ... and it requires a "Special Shim Tool" to do the 750 ... because the Shim Tool I have that works for 650 and 900 won't do a 750 ... you can loosen the Cam Bearing Caps and lift the Cam.

Caution:
Don't remove the Cam Caps.
If you remove the Cam Caps and the Camshaft "Gets away and rotates forward ... the Automatic Cam Chain Tensioner will immediately take-up the slack and make it impossible to place the Cam back in the Bearings.

This situation will involve removing the Cam Chain Tensioner and doing a Manual reset of the Cam Chain Tensioner.

A proper reset of the Cam Chain Tensioner is going to involve making a Gasket.
Adding sealant
Reinstalling the un-loaded Cam Chain Tensioner.

A job that ... unless you have the strength of a God, is going to involve removing the Carbs to get the Bolt Cap on the end of the tensioner ... working against the two spring within a spring tensioner springs.

 

So in a shim exchange program, everyone assumes that the shims don't wear at all, and remain square.
So why don't we do a shim exchange program thru XJBikes ???

except for those that already ground their shims, and ruined them.
Someone could ask $3.00 per shim and make a killin !

Plus postage.