What I learned repairing my Maxim X

Last summer my bike quit running. I had owned it for 23 years. I am mechanically inclined but would never have tried something like adjusting the valves...seemed too hard. I am writing this to inform any who may be considering adjusting their valves. As far as I am concerned there is nothing like hearing it from someone who actually did it.
Well I had nothing to loose so I tore it apart after doing a compression test that showed 2 cylinders seriously low. The first thing I learned is that those rubber grommets between the carbs and airbox will shrink and harden in time. Had I replaced them 10 years ago I would not be pulling my bike apart. That hit me pretty hard....I should have known something was wrong the last time I tried to tighten those clamps and it just was not going on right. I just did not know what was happening to those grommets.
So over the winter I decided to start repairing the bike. There were some small scratches on the cylinders from grit so that had to be fixed. I have a good friend who has an engine building business. He suggested I lap the valves then tested them for sealing. I also got them to hone the cylinders. This after finding a place on line to get my parts from as Yamaha had nothing and said they would have to order the rings from Japan!. I may as well givte he online guys a plug, they were very good to deal with:
http://www.powersportmarine.com/fiche_s ... detail.asp
I may also add that a local yamaha mechanic told me that the cams could not be removed without taking off the sprockets. He was wrong. The first thing to do is put the#1 cyl. at top dead center. I then cleaned off the chain & sprockets where I wanted to put some paint..this to make sure reassembly would be correct. It was snug but they did come out with a bit of carefull tweaking. I will ad here that it is manditory to remove the carbs to adjust the valves. This because the chain tensioner must be removed. It has a rachet in it that will not release when the spring is removed, the whole thing must come off.
The hardest part was adjusting the valves for me. I had taken the buckets out with a magnet then read how that could magnetize them. My engin builder friend told me they get magnetized by the constant striking from the cams anyway. I still wanted them demagneized so I got a unit to do that on Ebay.
Then there was the problem of all those shims. I was unemployed at this time and to save money I got a micrometer for a total cost of $10. on ebay and ground it down so it would measure shims. I then sanded any to the exact size I needed, after shuffling them as best I could to various new locations to get the gaps I needed. Another thing I learned is to check the gap carefully, the feeler should be quite snug to get a good reading. I had to find a tapered set to get in those tight places between the cam lobes. for what it is worth I hope this information is useful to someone here. Thanks to 'Maxim X' who gave me the info I needed to get the rings right and bolt torque specs.
I would not recommend doing this if you are not sure of your abilites, it is not an easy job IMO. Like a 9 out of 10 for me. I am very thankful to God for helping me get through all this. I started the bike for the first time today and it sounded pretty good. I am still a bit nervous as to how well it will run in the long term. Here are some photos to help with understanding my writeup.

 

Good write-up Forgiven. Checking the valve shims on the Maxim-X is not child's play. And there aren't many threads on this forum about this task specific to the X. The more that get's posted on this topic, the better I'll understand the task when it comes time to do mine.

 

One more thing I forgot to mention. I used my friend's torque wrench to put the cam caps on the first time. Typically the proper torque was met at 1/4 turn past just snug for each bolt. I did find some reached that torque sooner and you will get a 'feel' for that. I found one bolt tightened up quite quickly at about 1/8 turn...I did not force it further as the proper torque was achieved.
With this info you should not need a torque wrench to do the job. An accurate low reading torque wrench is not always available to everyone.
I also hope anyone who reads this noted the way the carb grommets shrunk as shown in the first photo. They are a must replace item when this starts happening, and no better time to do it as when the carbs are off the bike anyway while setting the valves.

 

I have a really good torque wrench...so shouldn't be an issue. I have a air leak somewhere that causes my idle to rise as the engine heats up. I think it's probably (or possibly) the grommets. Just need to find time to time to confirm.

 

The intake runners that bolt to the head have orings on them, that is a possible place for an air leak. An air leak on the other side of the carbs will not change idle, just allow dirt in, IMO.

 

Hmmm..hadn't considered that. Worth a look. I need to get by a hardware store and buy a propane torch. I've read on the forum you can take the unlit torch, release the gas, and move it around engine components. Supposedly when the engine surges from sucking in the propane you've found your leak. I tried it with starter spray with no luck...it seems too heavy to atomize enough to be sucked in and it just disperses everywhere. Not to mention being an atomized liquid (as opposed to propane gas) it coats whatever your spraying towards.