MisterP's revival/build thread: 1977 XS650

I would say, at this point, remove your coils, remove your petcock or petcocks. See if the tank will mount the way that you want it to with those removed. You just may have other issues in the way. The upper motor mounts may yet be an issue, depending on the width and depth of that tanks tunnel.
 
That's good advice. I just wanted to make sure the ignition coil and petcock issues weren't insurmountable before moving on to yet further issues that are moot if i can't solve the first one. i'm going to have some time to pull those parts off tonight and see about fitment. my theory is that with the coils gone i can use the old coil bracket to mount a bracket that will hold the gas tank pucks, put some rubber on the frame under the tank tunnel, and then slightly elevate the bracket in the rear (slightly) until the whole thing is level.

If it does you could install an inline petcock.

i'm googling these now. do you have a specific one you'd reccomend?
 
I don’t have a brand recommendation but make sure the barbs are the right size for your lines to connect to the tank and the carbs. One with a bolt hole would be good so you can stabilize it. You’ll need an in-line filter.
 
Nice tank by the way. Does its mounting points line up with the bikes?
not on its own. the rear mounting point lines up nicely, but the rubber puck holders are female, not male, meaning you have to do some modification to get the pucks into place. they're also in the wrong place to begin with. and then there's the issue with the width of the channel under the tank being too small to accomodate the ignition coils. it certainly doesn't just bolt on.
 
Finally some good news:

With the chinese tank full of gas on and the gas line successfully split into a T to feed both carbs, the bike starts and idles again. This is the first time i've heard it run in about a month and it complained a lot at first, then settled down into a 1200-or-so-rpm idle after a few sessions of starting it, revving it, and warming it up to get fuel through the carbs. It will only Idle on choke, however, which is probably due to the fact that I took the airbox off and haven't really messed with the adjustments on the carbs yet. However, finding out it still starts and idles and throttles and all that is a big win.

that said, my gas line running from the petcock to the filter to the T is way way too long.
2019-10-27 (1).jpg
I intend to futz with all that shortly, but I still need to get an in-line petcock installed because the one that fits on the gas tank hangs too low and rests right on the heads if i don't elevate the gas tank. I've found a few of these in-line jobbies online but if anybody can recommend a specific one that they know is good quality, again i'll be grateful. I think I have a good spot to bolt the petcock, but I still need to find some sort of barbed connector to stick on the gas tank outlet. I'm not sure specifically where to buy that sort of thing.

The gas tank is still sitting loose and elevated on the bike to get around the petcock and ignition coil issues, but i've decided to start figuring out what to do with the ignition coils. I took them off and was able to confirm that the gas tank does not sit at the correct height unless they're completely moved out of the way.
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At first i thought i could simply invert them or pull them back to a spot under the seat, but then i discovered they're connected to eachother by way of orange and brown wires. I haven't got a clue what the purpose of that is, but i can only assume it's not something I want to disconnect for any reason. I do not have soldering equipment, nor do i want to buy any. These orange and brown wires are connected to a third component seated just under the middle of the frame that I can't identify because i can't find a picture of it on any specific parts diagram.
2019-10-27.jpg
It seems to me that if i move the ignition coils i have to move this doodad too, and in order to get it all out from under the frame i have to disconnect these wires as well. This probably kills the idea of moving the ignition coils back and away under the seat. Any alternative suggestions are most appreciated. Some folks recommended changing to a new aftermarket ignition coil that might allow me to move it to a different location, but i don't know enough about what that entails. If anybody knows of a detailed step by step guide to changing one of these out it might be something i can approach.
 
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I have no kind words.

lol...ok? that was a bizarre waste of a post.

https://www.partsnmore.com/parts/?filters[category]=air+&+fuel&filters[fitting]=universal&q=petcock+adapter+plates

The above link should find you a proper adapter plate and a petcock adapter. That should clarify a part of it for you.
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This is awesome, however, it appears it's directed at adapting the OEM tank. that bracket and male threaded fitting will not work at all on this janky aftermarket tank. It looks like i'm going to need this bit instead:
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still, a totally successful suggestion. thank you. i'm gonna get that sucka on the way.
 
Kind words of advice. Find a stock standard tank to replace your was very pretty 77 tank.
:)
The fit and petcock location troubles just don’t seem to be worth the effort in this case.
Sorry but It’s hard to see it all go so troublesome... for ?
 
Yes, you're trying to do a custom install on something you don't know anything about, and you have no tools to speak of, lol. Moving coils is no big deal if you understand how they're wired, but you don't. You don't even know what that "mystery" component behind the motor mount is (your condenser pack). Sticking with a stock tank would be the best course of action for you.
 
Kind words of advice. Find a stock standard tank to replace your was very pretty 77 tank.
:)
The fit and petcock location troubles just don’t seem to be worth the effort in this case.
Sorry but It’s hard to see it all go so troublesome... for ?

Thank you for the advice but it's a question of money. a stock standard tank will cost me no less than $370 shipped by my best reckoning. this tank cost 80, and is perfectly functional for the time being. Unless somebody is willing to put together an approximately $400 donation fund to keep my gas tank stock, we're gonna have to stay with the aftermarket, lol.
 
FWIW, my XS650 runs Boyer Bransden ignition. This uses just one, dual output micro coil. The black box bit of the system fits inside the the frame gussets behind the headstock. The associated wiring is very simple, Boyer has a simple on-line fitting guide plus there are threads about it on this forum. I think it might help solve your problem with lack of space under the tank but I don't know how much the BB micro system would cost in USA.
 
FWIW, my XS650 runs Boyer Bransden ignition. This uses just one, dual output micro coil. The black box bit of the system fits inside the the frame gussets behind the headstock. The associated wiring is very simple, Boyer has a simple on-line fitting guide plus there are threads about it on this forum. I think it might help solve your problem with lack of space under the tank but I don't know how much the BB micro system would cost in USA.

That's worth a lot, thanks. It gives me a strong reference point for what a quality ignition replacement is supposed to look like. i've been going over the installation instructions at a glance and, given the time, it looks like something I could even do. The cost is around $220 minimum in the US. pretty steep. Still less than the cost of a stock gas tank, though, and from what i'm reading this ignition system would actually improve the operation of the bike. This looks like a good potential project if 1) im too stupid to move the ignition coils properly 2) i want to add something to improve the bike a little later. definitely bookmarking that part.

Thanks!
 
Well, i haven't been back at this for a minute, because I wanted to wait until I wasn't just futzing around and had some real tangible results. Today was a very productive day. What i've accomplished since the last post (it's not much):

Built and fitted brackets to re-position the rubber pucks that seat the gas tank.

Adjusted the height of the rear bolt bracket to get the tank into a position that will look level and true once the bike is in its finished stance. I did this by putting a ratchet strap over the triple tree and ratcheting down the front forks incrementally to achieve measurable amounts of "lowering" while placing spacers under the rear wheel to achieve measurable increments of "raising" until the bike sat the way i intend for it to sit. it's not much of a change from the original stance, but it leaves the tank perfect.

I removed the standard petcock from under the bike since it was too tall and was resting on the engine. It was replaced with a janky apparatus of my own design. I placed a brass cap over the nipple coming out of the bottom of the gas tank, drilled a hole right in the center of it, and then threaded that hole. I think screwed in a brass gas line elbow similar to the one shown to me earlier in this thread. from there I ran some gas line right to a tidy little in-line filter that was meant for an ATV. Honestly, i can't believe it worked as well as it did. no problems to report here. not even any leaks.

removed, disassembled, and went through the carbs. This is a big one. The bike was failing to run on anything but choke, running on one cylinder half the time, and running extremely rich, spewing gas-heavy smoke out the back. Once i took the carbs apart i found that some fool had put one of the jet needles in wrong. the thing was sitting all loose-like *inside* the vacuum piston instead of hanging through the bottom of it and seating into the needle jet. near as i can tell they slid it in *on top* of the needle holding doodad rather than underneath it, causing it to just pop right up as soon as sufficient pressure came out of the needle jet. On top of that the pilot jets from both carbs were clogged to hell. a thorough cleaning, de-clogging and reassmebling the jet needle situation. made a world of difference. once i got it back on the bike performed a regular, smooth, standard idle at 1200 rpms for the first time since i've owned it.

What's next? heck. I guess i'll put a temporary finish on that gas tank to make sure it doesn't rust while i continue working.

my next big step is that I have some jets on the way from Jets R Us to fine tune my now-functioning carbs. After that the wheels, chain, sprockets, rear brakes, rear fender, and battery box are all coming apart. The three big notes on my agenda are to clean the wheels up to be presentable, get new tires installed, make sure the rear brake is working as well as it can be, put new chain and sprockets on (gonna change the gearing ratio a bit), and hopefully take the first steps toward installed a compact battery so that I no longer need the battery box. in between all this I will be doing a lot of frame cleaning, de-rusting, and protecting the spots i clean. I've also got a plan to take a very close look at the swingarm to make sure everything is in order there before i carry on re-assembling all this.
 
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