Cam Gears Install Question

[BA80]

I don't know how much or if any difference it makes but that's the way it is from the factory.

[mack]

This

could turn out to be another arguable thread like oil and tires. I had one of the shim removal tools I bought back in 79. Gave it away. When I check the valve shims and if some need changing then I pull the cams and flush out the galleries and check the buckets for galling. Over kill? Probably. But I"m really good at pulling cams and reinstalling now. I also have a card with odometer, shim numbers ,last checked clearance and compression recorded taped to the underside of my tool box lid.

[mack]

Opps

forgot to say, mine was original and my cams and gears are the same as what greg shows.

[BA80]

could turn out to be another arguable thread like oil and tires. I had one of the shim removal tools I bought back in 79. Gave it away. When I check the valve shims and if some need changing then I pull the cams and flush out the galleries and check the buckets for galling. Over kill? Probably. But I"m really good at pulling cams and reinstalling now. I also have a card with odometer, shim numbers ,last checked clearance and compression recorded taped to the underside of my tool box lid.

Ha ha.....you and Bob Falter and Bohn Frazer would get along GREAT. They have a notebooks they carry with everything they ever did to the bike, when and where they put gas in it and what mileage they got between fill ups.

Bohn might even whip out his Plexus and clean your windshield if your parked next to him.

[TopCatGr58]

Hey Billy,

What's frustrating for me is that I had the valve cover off when I did the Carriage Bolt CCT mod, and I didn't check my sprockets and nipples!

As you have said, with the crank on "T", the cam dots DO line up, so if they will be out of time, it probably won't be but a few degrees, and you had been running that way before. SO...if you were happy with the performance, then I would say leave it alone UNTIL you go back into it for other maintanence and IF you feel froggy, you could then change the sprockets. JMHO!

T.C.

[BillyRok]

I haven't had time to put it back together yet, hopefully tomorrow, so I'll put it back together the way Greg and Nate said as mine was evidently bolted up wrong by somebody previously working on it.

[crazy steve]

I'll note that as the poster of the maintenance thread referred to, that I did research the info about the 'nipples' by the bolts before posting it. The FSM makes no mention of this (but it's not like they didn't fail to more fully explain some other stuff), but comparing to the motors I had on hand and carefully looking at the crummy manual pics, I came to the conclusion that's the way they're supposed to go. I don't see any damage being done from them being installed wrong, but having the cam timing off by a few degrees won't enhance performance....

Yamaha did go to the trouble on 'marking' these after all...

[BillyRok]

Before I put everything back together, I laid the two gears on the bench one over the top of the other with the two nipple holes at "12 o'clock" and found the teeth on both gears line up perfectly. Then I rotated the gear on top 180 degrees so the nipple hole was at 6 o'clock and discovered that all the teeth on both gears still lined up perfectly. I'm no expert mechanic but it appears that there is no difference in how the gears are bolted to the cam...still doesn't explain as Steve noted that for some reason Yamaha saw fit to mark the two bolt holes differently.

We need to find a retired Japanese engineer who helped design these bikes to join our forum to explain some of the mysteries we come across.

[BA80]

Just a couple degrees is pretty difficult to see with the naked eye. They are there and were installed that way for a reason.

[GLoweVA]

a couple of years ago when i had my cams out the first time ever, I put them back on and didn't know about the 'nipple' indicators, I wondered and wondered why the dots were off just a little whereas they weren't when I pulled the cams.
I then went on the site here and read that the 'nipple' indicators had to be up thus matching the dots.
Sure enough, I went back out and rotated that sprocket 180degrees and the dots lined up just like before i pull the cams.

Don't know why it works, it just does.

[TADracer]

Well I am speaking blind here because I do not have a set of gears handy at my desk AND, I have never checked the stock gears but, if there is any difference you might not even see it at the dots on the cams. Install a degree wheel on the crank and any difference will definitely show up. So if one camshaft is a degree or two off (which you might not even notice) by installing the sprockets backwards, then it will show up as two or four degrees at the crank.

Will it make a difference? Probably not. But I can tell you that a couple degrees of cam timing adjustment can move your power curve up or down in the RPM range and the effect takes place mostly on the intake cam. Now a tooth off and that can be disaster.

[IanDMacDonald]

We need to find a retired Japanese engineer who helped design these bikes to join our forum to explain some of the mysteries we come across.

I've commented on this before. Say hypothetically that the oldest engineers were in their 40's at the time of design, that would put them @ 80+ years old. Still possible that they're alive . . .

[MPittma100]

Cam Timing

Typically cam timing is adjusted or preset via the bolt holes that secure the gear and not so much the gear teeth. Cam timing changes are made by slotting the mounting holes and/or using an offset bushing(s).

Unless you are very familiar with cam timing adjustments and have the proper tools, your best bet is to install the cams/gears as outlined in the service manual.

It is a good idea to mark the cams (which hole, which side of the gear, which cam gear E or I) prior to disassembly. This way, there will be no doubts when going back together. Always use RED Locktite on the cam bolts.

[BillyRok]

Unless you are very familiar with cam timing adjustments and have the proper tools, your best bet is to install the cams/gears as outlined in the service manual.

I don't have my FSM in front of me right now but I read it several times and had it in front of me when I was removing and installing the cams...there was nothing in there about the difference between the markings on the bolt holes. The pics in the tech tip are what got me wondering. Not being the most experienced motorcycle mechanic, it seems to me that the FSM is written assuming the reader has a certain level of skill/experience and therefore some of the basic details are not always included. For example -

Always use RED Locktite on the cam bolts.

No mention of this in the FSM. Calls for 14 ft lbs torqued which I did. Then I got thinking that's not much, I don't want them coming out so I went a bit more to 16 ft lbs. Now I'm worried that I better pull the valve cover and lock-tite the bolts...even if it means resealing the valve cover back down (it's kinda a pain, and it didn't leak this time!) I can tell you that I turned the motor over several times to make sure the cam dots lined up with the marks when the timing plate was on the "T".

[BA80]

The Loctite is simply added insurance that the bolts won't back out again.