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First XS650 Build, What to Look For
- Thread starter SlowMaintenance
- Start date
SlowMaintenance
'76 XS650 Chopper
Ahh, that would explain why I couldn't find anything like it by searching for brake light switches! Thanks for the info 5T.
I actually found one of your old threads using this new keyword and I may do just as you did. Remove the wires and leave the bolt in there.
At this point I can either use the universal emgo one I already have, or buy one similar to this and use the hole in the backing plate to mount it.
https://www.amazon.com/12-0001-Univ...=8-3-fkmr3&keywords=yamaha+brake+light+switch
I actually found one of your old threads using this new keyword and I may do just as you did. Remove the wires and leave the bolt in there.
At this point I can either use the universal emgo one I already have, or buy one similar to this and use the hole in the backing plate to mount it.
https://www.amazon.com/12-0001-Univ...=8-3-fkmr3&keywords=yamaha+brake+light+switch
SlowMaintenance
'76 XS650 Chopper
So after much prodding from many of you on here, I decided to order a small battery for my bike. http://www.ebay.com/itm/271655920532
What sold me on it was information from some users who mentioned that they had ignition issues and trouble tuning the engine which was often misappropriated to the carburetor. When I did run the engine to get the timing set, I was having some issues with poor idle and the carb seemed to be jetted too lean. I'm wondering now if this wasn't an electrical issue the whole time.
I did some additional research and still have a few questions. I'm wondering why a battery performs better in this situation. Assuming both a battery and a capacitor are charged to the same voltage, in theory a battery would provide consistent voltage across it's lifespan until the point where it reaches the end of it's life and begins to lose charge rapidly. In a graph of voltage vs. time, this would be a horizontal line with a quick drop at the end. A capacitor would look more like a steadily descending line, losing voltage throughout it's lifespan until it is no longer functioning.
In a charging system however, like on our motorcycles, the PMA is sending energy through the regulator and back into the battery or capacitor. If the issue with the capacitor's performance for our application is due to the decreasing voltage during use, wouldn't the charging system be feeding the same amount of voltage that it's using? Or is that why people are having trouble closer to idle...maybe the voltage being supplied during idle is a net negative and this causes the dimming of the lights people describe. So that's a potential downside for the capacitor.
On the flip side, some have mentioned that using a small battery with a PMA can be dangerous because it can actually overcharge. I'm not sure why this would happen with a regulator in place, but I'm certainly no expert on this and am curious to know. If I run this battery I linked, I would hope that it would be more suited for long trips, as opposed to dangerous but just in a different way.
There is then the option of running the two in tandem, but I'm not sure what benefit this provides. Feel free to chime in if you've got any suggestions or if there's something I'm missing.
What sold me on it was information from some users who mentioned that they had ignition issues and trouble tuning the engine which was often misappropriated to the carburetor. When I did run the engine to get the timing set, I was having some issues with poor idle and the carb seemed to be jetted too lean. I'm wondering now if this wasn't an electrical issue the whole time.
I did some additional research and still have a few questions. I'm wondering why a battery performs better in this situation. Assuming both a battery and a capacitor are charged to the same voltage, in theory a battery would provide consistent voltage across it's lifespan until the point where it reaches the end of it's life and begins to lose charge rapidly. In a graph of voltage vs. time, this would be a horizontal line with a quick drop at the end. A capacitor would look more like a steadily descending line, losing voltage throughout it's lifespan until it is no longer functioning.
In a charging system however, like on our motorcycles, the PMA is sending energy through the regulator and back into the battery or capacitor. If the issue with the capacitor's performance for our application is due to the decreasing voltage during use, wouldn't the charging system be feeding the same amount of voltage that it's using? Or is that why people are having trouble closer to idle...maybe the voltage being supplied during idle is a net negative and this causes the dimming of the lights people describe. So that's a potential downside for the capacitor.
On the flip side, some have mentioned that using a small battery with a PMA can be dangerous because it can actually overcharge. I'm not sure why this would happen with a regulator in place, but I'm certainly no expert on this and am curious to know. If I run this battery I linked, I would hope that it would be more suited for long trips, as opposed to dangerous but just in a different way.
There is then the option of running the two in tandem, but I'm not sure what benefit this provides. Feel free to chime in if you've got any suggestions or if there's something I'm missing.
Can't answer why the battery is better for tuning, but using cap and battery is a little insurance to get you home should one or the other fail.
SlowMaintenance
'76 XS650 Chopper
Right, I keep hearing that as well. I'm not able to wrap my head around how wiring them in parallel actually works, but from what I've read the order doesn't matter. So maybe like this? Used light blue and dark blue for the two wiring colors. Does this diagram accurately show how it's supposed to be set up? (The other hot terminal from the cap would go to the regulator, not pictured below as it's not part of the system I'm wondering about)
Nick, Nick, Nick. Clear yer thinkin' about the life/voltage curves.
Google these two:
"Capacitor discharge curve" and "Battery discharge curve"
The capacitors used with these PMA setups, large as they appear, really don't have much in the way of storage capacity. It would take thousands of them just to equal the storage capacity of an AA battery. They provide just barely enuff voltage smoothing to stabilize the regulator.
In your diagram, above, yes, that's the correct way to wire them in parallel.
But, the capacitor isn't adding anything significant. It's like adding a grain of sand to a bucketfull.
It's okay to have it as a backup to a failed battery. You'd want to be sure that the bike runs fine on the capacitor alone. And, have a disconnect/switchover scheme so that you're not running both simultaneously. Saves the life expectancy of the capacitor by avoiding operational heat...
Google these two:
"Capacitor discharge curve" and "Battery discharge curve"
The capacitors used with these PMA setups, large as they appear, really don't have much in the way of storage capacity. It would take thousands of them just to equal the storage capacity of an AA battery. They provide just barely enuff voltage smoothing to stabilize the regulator.
In your diagram, above, yes, that's the correct way to wire them in parallel.
But, the capacitor isn't adding anything significant. It's like adding a grain of sand to a bucketfull.
It's okay to have it as a backup to a failed battery. You'd want to be sure that the bike runs fine on the capacitor alone. And, have a disconnect/switchover scheme so that you're not running both simultaneously. Saves the life expectancy of the capacitor by avoiding operational heat...
SlowMaintenance
'76 XS650 Chopper
Ah, good point. I remember reading that about the capacitor storage, but that it could discharge much more voltage in a much shorter amount of time. The guy in the video taps a piece of tinfoil across the terminals after charging it up and it blows to holes in it like lightning. Pretty cool. Again, not sure if that's helpful for our application, but cool nevertheless.
I'll take that advice, 2M. I'll get the timing set with my large battery. Move it over to the small battery to make sure it runs just as well. Then ensure it runs on the capacitor too. (Should I charge the capacitor first?)
That way, I can keep the cap in my tool bag as a backup in the event that my battery fails.
Thank you!
I'll take that advice, 2M. I'll get the timing set with my large battery. Move it over to the small battery to make sure it runs just as well. Then ensure it runs on the capacitor too. (Should I charge the capacitor first?)
That way, I can keep the cap in my tool bag as a backup in the event that my battery fails.
Thank you!
That's only because it doesn't have much in the way of storage capacity, compared to a battery. However, you can charge up a capacitor to very high voltages, up to its stated rating, and make it dangerous. A battery will tend to clamp charging voltages to its rating, making it safer, not just for the handler, but for the electronics too. In a way, its own form of regulation. The capacitor won't do that.
If the PMA regulator decides to go *bonk* and shoost 20+ volts into your system, the capacitor will say "Gimme whutcha got, I can handle it", whereas the battery will slow down that 20+ volt surge.
Sounds like a plan.
Make sure that your capacitor uses that isolating spring mounting...
SlowMaintenance
'76 XS650 Chopper
Tank and fender hit with the Spraymax 2K clearcoat. Research says the cure time is 24 hours. Anybody want to confirm this? If so, I'm throwing some gas in this thing tonight and see it she starts up!
PS: There's a dent in the tank, I bought it that way and didn't fix it. It won't be the last dent that gets put in this tank, so it doesn't bother me lol
PS: There's a dent in the tank, I bought it that way and didn't fix it. It won't be the last dent that gets put in this tank, so it doesn't bother me lol
SlowMaintenance
'76 XS650 Chopper
Battery arrived today and it's very small. I dig it.
Only question is how to mount it. Anybody got any ideas? I was thinking I could use that pandemonium regulator mount that came with my starter block off plug and zip tie the battery vertically and horizontally to that.
Alternatively, I could find some mesh, wrap it around the battery like a pouch, and zip tie that to the backbone.
Looking for an easy solution for a test ride. I kind of shot myself in the foot by going with the battery late, since I've already painted and would prefer not to weld anything now.
Only question is how to mount it. Anybody got any ideas? I was thinking I could use that pandemonium regulator mount that came with my starter block off plug and zip tie the battery vertically and horizontally to that.
Alternatively, I could find some mesh, wrap it around the battery like a pouch, and zip tie that to the backbone.
Looking for an easy solution for a test ride. I kind of shot myself in the foot by going with the battery late, since I've already painted and would prefer not to weld anything now.
SlowMaintenance
'76 XS650 Chopper
Good call, they may have that at my local hardware store
SlowMaintenance
'76 XS650 Chopper
Good news guys, I got her running smoothly! I still don't understand how though. It would run with the choke on (idle was SUPER high though, as if I was holding the throttle open) but when I would take it off choke it would die. This was with the 25 pilot jet in my Mikuni VM36 single carb application. This made me think the pilot was too lean since it ran with choke but not without.
Pulled the plugs and they were black. That says the opposite, must be too rich.
Tried a 22.5 pilot and it worked great. Bike took the idling better, and with some adjustment of the idle and mix screw, I got her to idle steadily and with a GREAT cammy sounding lope.
However, she dies after about a minute. I will say though, that I think this is because I don't have enough gas in the tank. It was way down at the bottom of my fuel sight gauge, and considering the petcock has a tube that sticks up, I'm thinking it was right at the line and probably was sputtering out. I'll test this theory tomorrow night when I'm back working on it again.
I'll also be setting the timing then too. I did the cruder method of using a flashlight to view the piston with the plug out to see when it reached TDC and marked the line with a paint pen on my PMA to the TDC marking on the sticker. Hopefully the timing is a straightforward process. My timing light has a tach as well so I'll set that idle to 1,000 RPM. Question on this though. Do you set the idle FIRST, and then work the mix screw? Wondering if it matters which order you do them in. I can't wait to get her running smoothly though.
Also, does anyone have the specs on the bolt that attaches the brake rod actuating arm to the drum? My bolt is missing and I'm not sure what pitch I need for the replacement.
Pulled the plugs and they were black. That says the opposite, must be too rich.
Tried a 22.5 pilot and it worked great. Bike took the idling better, and with some adjustment of the idle and mix screw, I got her to idle steadily and with a GREAT cammy sounding lope.
However, she dies after about a minute. I will say though, that I think this is because I don't have enough gas in the tank. It was way down at the bottom of my fuel sight gauge, and considering the petcock has a tube that sticks up, I'm thinking it was right at the line and probably was sputtering out. I'll test this theory tomorrow night when I'm back working on it again.
I'll also be setting the timing then too. I did the cruder method of using a flashlight to view the piston with the plug out to see when it reached TDC and marked the line with a paint pen on my PMA to the TDC marking on the sticker. Hopefully the timing is a straightforward process. My timing light has a tach as well so I'll set that idle to 1,000 RPM. Question on this though. Do you set the idle FIRST, and then work the mix screw? Wondering if it matters which order you do them in. I can't wait to get her running smoothly though.
Also, does anyone have the specs on the bolt that attaches the brake rod actuating arm to the drum? My bolt is missing and I'm not sure what pitch I need for the replacement.
SlowMaintenance
'76 XS650 Chopper
Almost meant to post this, not exactly build related but it IS an important item for a bike like this. This rothco seabag holds my tent, sleeping bag, sleeping pad, tool kit, extra clothes, food and more...and still has all that empty room at the top for more stuff if needed. When strapped to my sissy bar, full size back/head rest. Couldn't be any more comfortable. Also has backpack straps so you can take all your stuff to the campsite in one trip! And at $23 with Amazon prime, how can you complain? Love it.
Tested it out this weekend with my roadstar but looking forward to getting it onto the chopper
Tested it out this weekend with my roadstar but looking forward to getting it onto the chopper
Look at it thisaway. The influence of the mix screw increases as the throttle plate closes. If the throttle plate is open enuff, the mix screw may not give you any feedback.
So, given that, how would you proceed...?
SlowMaintenance
'76 XS650 Chopper
I love a good puzzle!
Given those conditions, I would think that setting the mix screw would be most effective with the idle set as low as it could go while still running steadily. Once set, I would then adjust the idle to the appropriate RPM.
Additionally, (and this may not be relevant but it IS carb related) I noticed the day after I was working on the idle that once parked and sitting, it appears the carb had purged some gas out of the lowest fuel purge line, the one closest to the float bowl. It had made a tiny little gas puddle on the cardboard below that line. Does that indicate an issue with the float level?
Given those conditions, I would think that setting the mix screw would be most effective with the idle set as low as it could go while still running steadily. Once set, I would then adjust the idle to the appropriate RPM.
Additionally, (and this may not be relevant but it IS carb related) I noticed the day after I was working on the idle that once parked and sitting, it appears the carb had purged some gas out of the lowest fuel purge line, the one closest to the float bowl. It had made a tiny little gas puddle on the cardboard below that line. Does that indicate an issue with the float level?
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Great! You're doing well.
There's a phenomenon that's common with carburetors that experience high temperatures.
For your next puzzle, do Google searches on:
"Gasoline boiling point"
"Reid vapor pressure"
"Heat soak"
"Evaporative emissions"
And, tell us what you think...
SlowMaintenance
'76 XS650 Chopper
Good keywords! Sounds like it may be unavoidable given the heat it's likely to experience, as that heat will cause the gas to expand and flood onto the ground. Though those keywords did lead me to some good reads about workarounds and how shutting the gas off a quarter mile before you reach your destination can at times be helpful. It also made me feel grateful that I have an XS650 and not a Toyota supra with a supercharger as it's nothing but Supra forums that come up when you search for heat soak lol. Those guys must love it.
The main learning though is that this is fairly normal, and I plan to not stress about it as my bike sits in a parking lot and not a pristine floor that I would be concerned about having gas on.
Thanks!
The main learning though is that this is fairly normal, and I plan to not stress about it as my bike sits in a parking lot and not a pristine floor that I would be concerned about having gas on.
Thanks!
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