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To shim or not to shim? What have you found at this mileage?


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I have my 1999 RSV with 37,*** miles on it pretty well disassembled for maintenance. I was planning on checking the valve clearances so I called Breyley Yamaha in N. Royalton , OH (they are supposedly well respected) to see if they have a shim exchange program to which the service manager responded that they do, he inquired if my valve cover gaskets are leaking and I responded "no why" he then asked why I was checking lash and I told him that I do not know the maintenance history of the bike and thought it may be a good idea since I was this close. The gentleman wanted to know if the bike was running well or and I said yes but it may need the carbs synced. I will be pulling the carbs out to replace the intake boots anyways and that brings up the thought should I pull the bowl off to measure the floats or should I use the sight gauge method as it seems to me it is the actual tell all of float level?

He then said they do not check lash on the bikes unless there is a reason to pull the valve covers off and when they do they rarely find the valves out of spec even on bikes with over 50K miles on them.

 

What is your take on the service managers opinion of not checking the valve lash? I am so close but yet if it isn't broke why brake it? I would be replacing the valve cover gaskets if I pull the covers.

http://i1352.photobucket.com/albums/q654/Pauljewl/20150322_111745_zps5o7v541g.jpg

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My thought is that if you are pulling the carb rack then you are right there and wouldn't take much longer to check the clearances. At 37K miles you will most likely be good. We did mine at 57K and had to change 3 shims.

 

My front end will look like that pretty soon.

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I would check them. I think that service manager is giving bad advice. I also think that he will be right about 7 times out of 10 but I wouldn't take that chance.

 

I think he'd be right 9 out of 10. But if you're number 10 and don't check them you're going to be in a world of hurt. The time from running poorly due to a tight valve and major damage due to a tight valve can be brief. You've already done most of the work, check them. I'd throw in new gaskets and the rubber grommets on the hold down bolts to prevent the leak that is about to start.

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Looks like your maybe 30 min from having the valve covers off. I think the service manual calls for right arounf 30k to check. Better to be safe than have a burned valve in 5k. I checked min around 26-28k or so. I had 2 out of spec and 3 close I swapped shims to make them well with in spec.

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I have checked the valves on the two Ventures I have had, both used bikes, the 86 I bought in 2007, unknown actual mileage, no adjustments made. The 02 had nearly 30,000 miles on it, checked them at closer to 40,000, no adjustments required. Not sure how often we are supposed to check them but it is a lot of work for no adjustments.

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After just having checked mine, and knowing how much work is involved in removing everything, (that you mostly have off at this point) and looking at how far you have it apart, and considering that you are going to take the carbs off, I'd for sure check the valve clearance. It's another maybe 15 minutes to take the valve covers off.

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Here is the thing:

 

The valves (particularly the exhaust valve) get very hot. They need to seat firmly against the head when closed to transfer that heat to the head and on to the cooling system. Over time the interface between the valve and the head wears, making the clearance less. When the clearance (hot, not at the temperature when you check them) goes away the valve does not close against the head and overheats. The valve will melt and be ruined. Hopefully it doesn't also ruin the head and you'll only need a valve job.

 

On a brand new engine the wear between valve and head is fastest, until they wear to where they fit each other very well. On many engines the initial clearance check is at relatively low mileage to account for this, and the later service intervals are farther apart.

 

How fast they tighten up on a new engine depends on how well the valves were fit at the factory. Typically the Japanese manufacturers do a very good job with this and you find they just don't move much. BUT - once in awhile one doesn't fit particularly well and it'll tighten up fast. If that happens on your engine and you don't check it you'll be the guy pulling the head for a major repair. I explain this to my customers all the time: Odds are they are wasting their money, but if they're the unlucky 1 in 100 and don't check it they're going to get burned.

 

It's like insurance. You don't buy insurance because you know your house is going to burn down, you buy it in case your number comes up.

 

Besides, the gaskets and o-rings are getting old and brittle anyhow. Soon they'll leak and you'll be pulling it apart to fix the oil leak. You're most of the way there, just do it.

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So close to the guts of the matter, might as well check them, and gain the experience for the next time..

 

I had purchased my used 2006 Midnight in 2008 with 20K miles on it, and while visiting in Texas I dropped in to visit Goose who showed me how to do the job properly (thanks!!) Talk about a meticulous mechanical genius..

 

If I remember correctly, all shims needed changing and what a difference in performance and ride. I think the bike had around 30K miles on it then.. The next time I did the valve clearance check was around the 58K miles mark and only half required changing.. still just within spec but while the guts were open, might as well bring them well inside the specs.. Found the valve stems had a lot of hard carbon built up on them and had those cleaned up..

 

Did it once again at around 100K miles on the bike and only 3 shims required changing, again just within spec, changed them to be well within spec.. Bike currently has 130K miles on it.

 

One thing I remembered Goose telling me was about the bare knuckle check on the gas tank.. Before the first check, he asked me to press a bare knuckle against the gas tank and feel what the 'buzz' or high frequency vibration felt like.. After the valve shim adjustment, that 'buzz' was gone.. nice. Before each subsequent valve clearance check I'd so the same thing and yes, noticed less of a buzz afterwards. Honestly don't know if this is gospel but based on what I experienced and observed, it works for me..

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Hey Puc! How often do you check the valve clearances in your extensive experience with Yamaha V4s?

 

Gonna sound crazy,, but in all honesty BlueSky - never... I just buy old unloved and unwanted 700 dollar Ventures who are laying around suffering in someones garage and wanting nothing more than to finish its life out with me just chasing the wind and together - we go for it.. My first one, a Blonde 84 Royale that I rescued out of an Estate Sale with a bad stator, ran out to well over 200k before she lost a crankshaft - no idea where the valves ended in her but she was still running on all 4 even though the crank bearings sounded like they were gonna come right out the side of the case - she still held matching compression on all jugs when I retired her too!! Amazing motors these V-4 watercooled Yam engines are..

Yea,, I know,, I am holy terror when it comes to my love for these lowely old bikes!! I am the same way in the area with the whole 2nd gear issue ,, 4 of the 5 I have ridden out now (Tweeks included) have lost 2nd gear fairly early in life and I just short shift em to give em a chance at enjoying what time they have left and accumulate some fun miles before the next one begins its journey.. Tweeks tranny departed ways with its 2nd gear back around 40k, that spot is nothing but a false neutral now that she has over 200k on the short shift.. She just takes a licken and keeps on ticken...

Wanna hear something really crazy? When I was out in Oregon last year at The Dalles Rally, one of the guru gear heads that I had the honor of meeting out there was standing there listening to Tweeks run, with a smile on his face he asked me what I was going to do with Tweeks when she finally decided she had seen her fair share of miles.. I laughed because someone else had recently mentioned that she should be stuck in a museum somewhere and I told him that. He said he would LOVE to have me get her drive train to him so he could dismantle her and see what things looked like internally. Knowing this person like I do, I am SURE he was very serious and would be found measuring and recording wear specs on everything from valve shims to cam chain slop on a 1983 Yamaha V-4 with 300k miles that had never been opened up - a shear miracle after being in a relationship with the likes of me!!!!!!:7_2_104[1]:

 

 

 

HEY MOTIV - YOUR RIGHT THERE - CHECK THOSE VALVE SHIM CLEARENCES!!!:thumbsup: MURPHYS LAW DEMANDS IT!!!

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  • 1 month later...

The results were 6 valves out of spec and 5 more flirting with the lower limits. tell ya what it's a bit of work to get them all set right.

More importantly when looking for shims and a tool the general manager at Breyley Yamaha Inc. 11035 State Rd. Parma, OH 44133 (440 237-4543) Rented me the valve tool and gave me a bunch of used shims with the understanding the same amount of used shims make their way back to him along with the tool.

This act of kindness from Dave Liddy will cause me to look them up when I need parts for the bike. Dave has been wrenching on them for 39 years and is very knowledgeable and has a nice old school dealership, not one of those multi brand palaces with too many bikes one can not get intimate with a certain bran they sell just Yamaha.

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I just finished doing my valve shims over the weekend with 55K miles on the bike. Not a single valve was in spec. And there were a couple that were down to about 0.001. It did not have another season left in it. My valves are now all right on the high limit, I only had to make 3 custom thickness shims to get it all perfect.

 

My vibration at 3,500 rpm is now gone.:confused24:

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