1976 XS650 restoration and rebuild, advice and help welcomed!

[GeorgeOC]

Ive been working on the front end, which will lead me towards getting the headlight bucket ready for the wiring. Tonight I rebuilt the instruments, replaced all the hardware, dampers etc, weather seals, and bulbs. Here's how they sit. Lets hope she can make it 10852 miles...

 

[GeorgeOC]

One thing I have noticed, is that the head light bucket seems to not fit so well... Its entirely possible one of the ears might be slightly bent, but they look pretty symmetrical without the bucket in place. But the bucket seems to splay the ears out, so that they're not flush with at the mounting points.

Is this a common problem? I've poured over the exploded views for this area. I wonder if anyone else has had the same fitment issues...?

 

[geedubya]

G'day George,
Did you manage to find new dampers for the gauges??
The ones that go between the gauge/bezel and the gauge housing?
I found some new ones from the local Yamaha dealer but with a later P/NO.3H3-83513-00.
Not expensive and the gauges seal just peachy in the housings.

 

[TwoManyXS1Bs]

One thing I have noticed, is that the head light bucket seems to not fit so well... Its entirely possible one of the ears might be slightly bent, but they look pretty symmetrical without the bucket in place. But the bucket seems to splay the ears out, so that they're not flush with at the mounting points.

Is this a common problem? I've poured over the exploded views for this area. I wonder if anyone else has had the same fitment issues...?

George, I had a similar problem. Ears not bent the same, accident history. Your right ear appears to be bent inward more than the left. I had to come up with a pinch/clamp jig for the ears, and carefully work them. Try a length of allthread, largest possible diameter and sized to fit thru and between the ears, like what the guys here do for spreading axle plates. Sandwich the ears between thick rubber washers, thick fender washers, nuts. Space the ears to match the headlight width, snug down. Then, grip the middle of the allthread and force it left/right a little to get the ears to conform. Gads, I hope that makes sense...

 

[GeorgeOC]

G'day George,
Did you manage to find new dampers for the gauges??
The ones that go between the gauge/bezel and the gauge housing?
I found some new ones from the local Yamaha dealer but with a later P/NO.3H3-83513-00.
Not expensive and the gauges seal just peachy in the housings.

Dubya, yes thankfully found some of those... The originals were absolutely shot!

 

[GeorgeOC]

George, I had a similar problem. Ears not bent the same, accident history. Your right ear appears to be bent inward more than the left. I had to come up with a pinch/clamp jig for the ears, and carefully work them. Try a length of all thread, largest possible diameter and sized to fit thru and between the ears, like what the guys here do for spreading axle plates. Sandwich the ears between thick rubber washers, thick fender washers, nuts. Space the ears to match the headlight width, snug down. Then, grip the middle of the all thread and force it left/right a little to get the ears to conform. Gads, I hope that makes sense...

TM, yes I think that makes sense... Thanks for weighing in! I think I may have a tool for the job. Tell me if this sounds right... I will need a longer piece of all thread, and run it through both ears, fix the internal dummy width (of the headlamp), then snug down from the outside with the fender washers in place... Luckily I have these great steel pressing adapters for work on bicycles. They fit like a glove!

 

[TwoManyXS1Bs]

George! Yes! That's it.
Meeting of the minds. Love it...

 

[GeorgeOC]

George! Yes! That's it.
Meeting of the minds. Love it...

!

 

[MaxPete]

Wow - everything looks so nice and clean George - very snazz!

 

[GeorgeOC]

!

I'd say that worked out. Thanks TM!

 

[theDQG]

Glad I found this thread.. getting a lot of useful information. Following.

 

[MaxPete]

Yup - there are several like this and the long term know-how that is being generated and exchanged among the various participants is absolutely priceless.

Cheers,

Pete

 

[DanielBlack]

Really beautiful work George, well done.

5twins, question here:

I wouldn't recommend setting your intakes at .002", that's a bit tight. Use .003". It's become common practice to use 3 and 6 on all models. As you can see by the specs listed in that link, Yamaha changed the recommended settings several times over the years. I have no idea why. The motors never changed all that much. My '78 speced .004" for the intakes and I tried it but they ticked like crazy. Closing them up just .001" to .003" quieted them right down.

.003" is deemed Goldilocks' preference. .004" is too noisy, .002 is...?

I've been setting my '77 at the book's .002", what might I expect at .003"?

 

[MaxPete]

...you might get a tiny bit more noise - but I doubt it will make much of a difference. One thousandth of an inch (0.001") isn't much in a machine in which the temperature can vary as much as an air cooled motorcycle engine.

Basically, too loose isn't good because it is noisier and if you set it REALLY loose, the valves won't open enough to do their job - BUT - too tight is very bad because the valves might not completely close and that will cause the cylinder to misfire or worse, burn the valve.

Others may differ, but I would err on the side of a bit too loose if I were you.

Peter

 

[5twins]

Too little clearance doesn't allow much oil to get in between the stem and adjuster. Try the .003", it shouldn't be much louder, if any louder. .001" isn't much but it can make a difference in noise levels. Mine at .004" were real clickers. .003" quieted them right down. I'm back to .004" now but I installed the elephants foot screws during my rebuild. They run quieter so the .004" is fine now.

There are some write-ups that claim larger clearances give more power. Once I had the quieter running adjusters in there, I experimented. I didn't notice any power differences with bigger clearances and even though the adjusters are quieter, they will make noise if you run them too big, like the .010" to .012" those write-ups were talking about. I ended up pretty much back at the normal suggested settings for my '78 model, .004" intake and .006" exhaust.

 

[DanielBlack]

Off-forum reading suggests racers might want tighter clearances for longer durations and bigger breaths. But, that could lead toward quicker valve train wear necessitating more frequent adjustments. And as Pete points out, too tight can cause valve burning etc. Not a problem for race engines that get pulled apart so often.

General-use engines are better served by looser clearances. Safer for valve trains, longer lasting adjustments.

But, too loose is too noisy. And too, too loose won't let the valves fully open.

So, err on the loose, but not too loose side of things. The book specs range .002-.004. .004 is too noisy. .003", it is.

Thank you.

 

[MaxPete]

Yup...its sort of a Goldilocks and the Three Bears type of thing:

• this valve is toooo tight!
• this valve is tooooo loose!
• ...and this one is juuuust right.

 

[DanielBlack]

.003" is deemed Goldilocks' preference. .004" is too noisy, .002 is...?

Indeed! I just figured .002" couldn't have been deemed too quiet!

 

[GeorgeOC]

Here's one for the community... While working on the PAMCO install, I laid out the coils and the plug resistor caps. The caps are NGK 5k, shipped with the kit form Mikes, intended for a threaded type plug. #14-0907. The kit did not include spark plugs. I had a set of new plugs however, but they are solid terminal end. What's the best plan of action? Replace the plugs, or replace the caps??? Is threaded or solid preferred?

 

[MaxPete]

The little end cap simply unscrews from the top of the plug George.

Just hold the plug in one hand and unscrew that cap with a pair of pliers (they're not normally very tight). The little threaded stud that the cap is on is a perfect fit for the NGK high tension wire ends.

Pete