Maxim X - valve clearances - NONE in this case

As the subject implies - I was able to measure my valve clearances with my "custom" made Craftsman feeler guages - $5 thank you very much Yamaha!

The intake side had zero clearance! I was surprised because I expected valves to get looser over time, not tighter! The exhaust was also tighter than spec, but more than zero. The intake was so tight that I could not even get a piece of paper in there.

Has anyone run into this before? I mean not having any clearance? How do you calculate the new shim size? If I plug in 0 clearance for the table- I might get the new shim size wrong, because with zero clearance, the spring could still be compressed - right?

Before you ask, I did a leakdown test of one of the cylinders before removing the cams, and it had a pretty pronounced intake leak while at TDC. So I know for a fact that the intake valves are not closing all the way. This is probably the main cause of my low compression. I did hear some leakage in the crankcase, but not near as much as the intake noise. I heard no leakage in the exhaust.

This brings up another point: I saw in another post to adjust the valves to the SMALLEST clearance allowable. That means with any wear at all, the valves will be out of spec again. Why wouldn't you adjust to the largest clearance allowable? That way, they would have longer before they would be out of spec. Right?

I am also bummed out because Yamaha told me these shims were going to cost $15 - $20 each! I have 20 valves, so that is a LOT of money! Does this price seem reasonable? Is there anywhere to get them cheaper?

Thanks in advance for the replies!

 

Hey richard03;
Yes the valves do get tighter, as the valve wears against the valve seat it will wear into the seat and thus make the gap smaller.
I got lucky with my dealer, they swapped out my old shims for ones they had in a collection of shims.
Theres also a shim pool on another list. You send them $15.00 and the size shim you want, they send the correct shim, you send them back the old shim and they send your check back. Not a good option when you have so many. I'm not familar with the X but mine all had the size on the back side of the shim. It may be possible for you to swap shims around with each other. and get some of them adjusted , then use the shim pool for the remainder. I'm not sure if I can post another list here so I'll send you a PM
And it would be wise to set them to the wider setting, to keep them from getting tight that much sooner.
That may have been my post you read, because I thought the same thing.


On another note, if you have zero clearance then add a shim that would put you at the higher clearance, if it was truly zero then you'll be right on. If it wasn't zero then at least you should be able to get a measurement and go by the chart from there.

 

The shim pool was mentioned at XJowners.com too. I've never been able to find it. I would greatly appreciate it if one of our members could clearify that one for the rest of us so we can link to them. That would be the way to go. I did exactly as you suggested Rich48, I swapped my shims around and only had to buy 1 shim instead of 4. Richard03, make sure you mic out all of your shims for their true size, they will wear and be thinner than the number printed on the back. Calculating your issue would be as simple as slipping the thinnest shim you have in there and checking clearance again. Failing that, I have hit the junk yard or a maintenance shop to source "new" used shims at $5 a pop or less.

 

Thanks for the replies. I am not sure if I want to wait that long for someone to mail me shims!

Has anyone actually experienced the shims being smaller than marked?

My shims look like cups, and the markings are on the round sides. Is this what other peoples look like? They actually look like miniature lifters, and the cup part of the shim fit over the end of the valve stems.

A little bit of an update. I leakdown tested one of my cylinders again with the cams and lifters out. The intake leak was so significant that I couldn't even keep my hand over the carb boot because it was pressurized instantly! Does this mean my valves are stuck? Does this mean they are bad in some way? Cut seats?

 

Hey Robert;
The address is www.xj-owners@micapeak.com
just inquire about the shim pool. someone will get up with you.

richard03;
I just found in the cd that the maxim X shims are marked on the sides and not the bottom like mine. WOW i'm glad my valves were not that involved, looks like a job. Now I see why you need thinner gauges, with 5 valves.

 

Yes, I have had shims that are thinner than marked. Wear, even upon hardened steel is inevitable. Thanks Rich 48, I'll try them out.

 

Am I the only one that cannot access the above link?

I just found out that my shims are different than everyone elses! Mine are cup shaped, with the cup part fitting over the valve stem, and the bottom riding against the bottom of the lifter. That is why my sizes are printed on the side.

Does anyone else have shims like this? If so, are these shims part of the shim pool? Yamaha wants $10 each for these shims.

 

The X is totally different from an 'ordinary XJ' in the valve department.

The X uses a pad, which as you say, sits on top of the valve stem underneath the cam bucket.

It is not the same thing as a shim which the non 20 valve XJs use. I don't think there is an official 'pad' pool.

Zanottimotor.com are charging $4.99 plus tax and shipping per pad.

 

Thank you so much! You were right, and you are going to save me $100!

 

With these shims:

If you need them smaller mark the location of each shim. Then gauge them, get your clearance. Note what size you want them to BE.

Take to nearest Machine Shop and have them grind them down on a surface grinder. Providing your taking off only around 4-5 thousandths you will be fine. The shims are pretty hard. They are also thin, so when heat treated they are almost completely thru hardened.

I personaly ground my own down in our shops tool room.

 

Thanks for the input. I actually ground down mine last night. I had to take off 8 thousandths though. This is because all of my intake valves have no clearance. I am going to put these back in as a starting point. Hopefully it will reseat the intake valves and I will be able to get a measurable clearance! I was then planning on ordering the correct size shims after measuring one more time. Hopefully this will prevent me having to take my head off and grinding valves!

 

Well honestly your probably still fine @ .008" removal.

By the time you harden something that thin its just hardens through

Im an advocate of being cheap. Why buy if you can make.modify?