Help with the XS650B air boxes

I've been able to use the search funtion to answer most of my questions but so far I haven't been able to find the answer to this one.

Let me back up a bit. The bike is an XS650B (1975) and did sit unused for a long time. When I got the bike (still a non runner) the airboxs had been taken off. In the deal, I got a couple of (still in the box) Yamaha air filters. I didn't pay much attention to them because I had other stuff to do to try to get the bike running and figured I'd get to them in time.

Well the time came this morning. I cleaned up the boxes and gave them a new coat of paint and all new rubber bits. When I went to install the new filters something didn't look right. ( I had printed the page out of the parts book and had that with me) As it turns out the filters are for a later model (533-14451-00-00) so I was thinking I need to order the correct ones. BUT, there have been a couple of bits on this bike that didn't add up to 1975. Like it has a 1976 type side stand and early type (two hole back) petcocks.

So what I'm wondering is...........................

Is there a phycial difference between the 1975 air box and lets say a 1977??? If there is, what is the difference?

Also, my boxes did not have the springs (element set) with them (447-14468-01-00) what do these look like and where do they go?

I did find something the 5twins wrote:

"There's no need for the filter to be open on the back and fit up snug to the cross over. The cross over will do its job just the same (equalize pressure between the two boxes) whether the filters press against it or not. Yamaha probably realized this after a couple years and re-designed the element. No doubt the new style was easier and cheaper to make too. You could probably just run those later filters in your '75 boxes."

Just trying to figure out this last littlle bit before I give it a kick.

Puzzled in NC.......Gordon

http://www.biker.net/650parts_index.html
Go to above site, look at the intake drawings for the various years, compare the specific part numbers, try to figure out what you have and if it will work.
The "spring" is actually a plate, not a coil spring, that tensions the filter element, holding it in place.
Unless you are trying to do a "correct" restoration, you can avoid a lot of headaches and save a lot of time by just ordering a pair of UNI filters, part # UP-4200, and ditching the whole air-box set-up.

Dog.....I've poured over those drawings....I see a change in the filter but not the box. I figured (by the drawing) the spring wasn't a coil type...just can't figure out where it goes. I don't have any and don't see where it would have attached.

I'm not a "restore" kinda guy but I'm also not a chop either. I like the way the airboxes work....pretty simple and my guess is effective.

I went ahead and slipped the later type filters in the boxes.....looks like they will work from what I'm seeing. At least long enough for me to try to start it tomorrow.

Thanks for taking the time to reply.

Gordon in NC

The spring is a slightly bent rectangle of metal with a hinged pull-ring on it, maybe 1 x 2 inches from memory. It slides into a little depression on one side of the air box, pressing against the filter. Again, look at the parts drawings.
Also, find the part numbers for the spring, find the variations for all the years, and search those numbers on eBay. Also try variations of "xs650 element set spring" and other combinations of terms on eBay. Best yet, forum members get rid of their air boxes every day, start a thread in the "wanted" section of the forum.

The "spring" is a bent strip of spring steel, as the drawing pretty well illustrates. They are available from Mikes, or probably better yet, used from someone switching to pods .....

http://www.mikesxs.net/product/99-5006.html

I know the listing says '76-'79 but I'm pretty sure they'd work fine on the '74-'75 set-up as well. It's not a complicated set-up. The clip simply jams in between the back of the filter element and the back of the airbox, holding the filter tight to the front of the box so it seals to the intake bell .....

Thanks fellows.....that clears it up for me.

I did try to search it, but couldn't find it. I'm kinda burnt out right now.....it took 20 pages of posts to find a photo of the darn gas cap. Took it apart and for the life of me couldn't figure out how it went back together. I know now though.

I was close to trying it tomorrow.....the weather's going to be nice and I could roll it out of the shop and give it a kick. BUT....all I had left to do was static check the timing. I'm doing something wrong or....something's wrong with the bike because no matter what I do it seems to be 180 degrees off.

Back to the search function......ugh

Chin up in NC.........Gordon

just swap the leads up by the condensers. the advance rod can be installed 180 off over on the advance weight side.

Yes, what gggGary said.
It is so easy to make a mistake and be 180 out that I don't even try to get it right any more. I just try to start the engine. If it's right it starts, if it's wrong it backfires which means you swap the leads as was said.
I find static timing to be a very rough estimate, once started you need to do dynamic timing with a timing light.

Assembling the advance rod correctly is pretty easy if you just follow this .....



If you have the locating pin on one side pointing 180° from the pin on the other side, then the timing will be 180° off. It's difficult to see the pin location on the points or Pamco side because the nut and lock washer cover it many times. I mark it with a Sharpie .....



The pin slot in the little disc on the advance side is usually visible and easy to see .....

5twins,

Thank you for the help and I hope you know how helpful your photos are.

This poor bike "ran before it was parked" which as you well know usually means something more along the lines of "ran before it didn't". But, I have a feeling the fellow was telling the truth and for the most part the bike has had very little wrenching on it. A few years after the original owner passed away, some of the younger boys in the family used it off road for a bit and it does show those bumps and brusies.

Unless somebody switched the wires while changing points....I don't think any of the rest of the bike has been apart.

A quick look through the threads the search function came up with had PLENTY of the same problem I was having and I saw the fix you mentioned on at least 2 or 3 other threads.

So, I go back down to the shop and sit down next to the bike again and take a close look at the wires going to the points. My wiring diagram doesn't show which side gets what wire.....but from the looks of it I would have routed the wires in there just like the were.

I swapped the leads at the connectors up by the coils. Same result????????

Hmmmmmmmmm I've been static timing points as far back as 1968 and I have no clue what I'm doing wrong......BUT I'm sure it's something I'm doing. So I ditch the homemade light bulb rig I've used for years.....put the meter away and go find the thinnest feeler gauge I have....001" and go after it by pinching the feeler gauge inbetween the points and "feeling" when the points start to open. I can't see s#@t anymore but I did it by feel several times and BINGO!!!!! like magic the timing is dead on. (okay....how about close enough that it should run so I can get a light on it)

I can't wrap my head around what I was doing wrong but I'll keep it in the back of my mind until the light bulb comes on (pun intended).

Tomorrow is the day I try to wake this thing up after it's long sleep.

Fingers crossed in NC (thanks again for all the help).....Gordon

1975 XS650B we'll see if it runs tomorrow
and a few BSA unit singles

Okay this isn't be the first time I've replied to myself....and it won't be the last.


and I'm as happy as a little girl

Had to coax it a little. After 10 or so kicks I pulled the plugs and they were bone dry, so I wet them with a little gas. 2-3 more kicks and nothing.....damnit, what have I got to lose?...so I tried the STARTER (what a wonderful invention!) on the second or third attempt...IT STARTED!!!!!! After that, all it took was just touching the starter button and it fires right up....I'm going to get spoiled.


No smoke, no strange noises, a little tweeking and it idles like it's supposed to. What a BEAUTIFUL exhaust note. I had to laugh to myself listening to the engine run. You can hear parts moving around but after all the stuff I'd read about it being noisy some of those fellows should do a couple of thousand miles on one of my BSA B44s.

BOTH of my rebuilt petcocks leak but I can deal with that and I'm off to the search function to see what the fix might be. Got the rebuild kits from Mikes....they're leaking from the 4 hole gaskets.

But all in all......I'm happy and all I need to do now is fix the petcocks and recover the seat and we'll go for a ride.

Thanks for all the help......"It's never to late to start wasting your life"......Gordon in NC

1975 XS650B it's a RUNNER!!!!!!
and a few BSA unit singles

Don't believe you..........never seen a pic of your bike yet so how do we know your not some spammer/scammer

650Skull said:

Don't believe you..........never seen a pic of your bike yet so how do we know your not some spammer/scammer

Click to expand...

Okay you asked for it mate

I'm the third owner. I got the bike from the son in law of the fellow who purchased it new in 1975. That fellow passed away in 1985 and the bike sat pretty much unused since then. During some of those years it spent time in a building where cars were being restored.....and the poor bike was left uncovered and got covered with grey primer.

My shop is narrow so it's hard to get a good side shot.

Here's the bike the day I dragged it home along with some of the loose bits that came with it.



Here's some close ups of the primer.......ugh





Here's the tach we already talked about



The seat cover was a total loss.....I tried but couldn't bring it back.



Carbs were stuck and so was the clutch....I've pretty much been working on it every day since I got it trying to get it to a point where I could see if it would run.

Here's a photo of it today right after I had it running. I drained the tank to work on the petcocks and had just rolled it back in the shop.





I still have to sort the petcocks and the front brake......recover the seat and I'll get to ride it around a bit.

I love it so far........Gordon in NC

1975 XS650B it's a runner
and a few BSA unit singles

Good job so far. looks a whole lot better now. I'm a bit partial to the 75. I think it's the best paint scheme of all the years.
If those tires came on the bike I would change then before you ride it. Old tires are dangerous tires.
On fixing the front brake, Rebuild the caliper, most often just a tear down, clean and reassemble. I would replace the master cylinder with one from a 77 up XS650. Your stock M/C is a 16 mm bore, The 77 up uses a 14 mm bore. This slightly smaller bore size will increase your breaking power and give much better feel.
Replace the brake line. That old rubber is bad. New rubber is ok but a braided stainless steel is better.
Leo

Congrats!!! What a great looking bike...and so much cleaner without all the primer on it!

Yup, your doing a fine job getting her back on the road. Yeah, the first engine run is always a rush.

Ok ok i believe you........................

Very nice, done a great job. Looks like the primer may have saved some of the chrome. Those 74/75 Mufflers are heavy sob's but i think they have the best look, (old style), and sound of all the XS650's .

Thanks for the kind words fellows. I just cleaned things up while I was waiting on parts....not wanting to get to deep into it until I knew what kinda shape the engine was in. The bike has less than 8000 miles on it and it really doesn't look like many wrenches were put on it. All the fluids were drained and it was kept in the dry. Back in 2004 the son in law thought he'd get it back on the road.....that's where those tires came from. Bad part is the primer....it's a pain to get off. One of these days it'll get torn down to a bare frame and the primer will finally go away. But it's a rider for now and it'll stay that way for a while. I have enough projects to last me untill 2050 and I'm just going to ride this one for the time being.

Take care....and THANKS for the help, Gordon in NC

1975 XS650B it's a runner!!!!
and a few BSA unit singles

I think this 650 is going to grow on you. I feel it's the perfect local bike. Big enough for occasional highway use but small enough for easy around town maneuvering. It's also just heavy enough so it rides well. Until I got the 650, my local ride was an SR500. The 650 has replaced it and I like it so much better. You may find your 650 doing the same, winning out over your smaller singles.

Hi Guys,

Well, Gordon, you've done a beautiful job so far, and you *totally* understated the amount of primer on the poor thing!

Sorry---I should have remembered about the 180-out timing thing....

Guys, don't mention the SR500 around Gordon! He is World-Class crazy for Brit singles, and if he get's his claws into an SR500, it's all over.....

Gee. My first post since 2012. My, how time does fly.....

Barb