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Newbie with a '78 xs 650 looking for wisdom.


DirkaDirka
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hello, my name is Derek but call me Dirka. ive been riding since i was about 12, started out beating around in the dirt on the farm with a '86 KDX 80, then a '89(i think) YZ80, and finally a '91 YZ125. that satisfied me till i turned 16 and could hit the streets legally. so thats when i got me a 79 honda CB500 custom. i rode that thing as often as i could till '04 and sold it back to the guy i bought it from for the same price i paid. in '02 i went a little crazy and bought a new CBR 600 F4i. that thing was a blast to ride especially in the twisties. they dont call them rockets for nuthin. i ended up selling that one too back in '04. then i went the next 5 years bikeless. not cool.

so a couple days ago i bought me a '78 xs 650. i plan on chopping the arse off of it and making a bobber out of it. its a good running bike. well it was when i rode it home. i bought it knowing that one of the petcocks leaked. i have had that damn thing off and on and my tank filled and drained about a dozen times. i rode it a little in between. ran good. thoght i had it fixed, got about 2 miles from home and puuuuhh. done. as of now the petcocks are back off and in pieces, but i know what i need to do to fix them. once i fix them and get them back on i will have to figure out why it wont run. i know the batt is not hardly charged. will the bike not stay running with a low charge? it will start but dies in a few secs. any advice?

78XS650.jpg

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You need to know what system isn't working. Is it fuel or spark? An inductive timing light or some other way of monitoring the spark will show the if the fire quits working after the few seconds, if the troubles electrical, or you might try to keep it running with a spray can of ether (starting fluid) letting you know it’s not getting fuel….

Once you know that you’re on your way to fixing a problem… It should run on a weak battery but a sound charging system

Are you trying the start with the starter button? If that’s the case the battery’s OK,

Does the “prime” position on the petcock free flow? (And does it run OK in prime?)

System first.. Elect.or Fuel.. Find the problem then fix it…

Good luck…

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thanks for the reply Stringal. i was kicking it cause it kicked so easily. since the original post i had the bike running again. i have fixed my petcock problems with a little redneck engineering. i did the flip flop of the petcock selectors which i read about online somewhere. whittled down a small dowel with an o-ring on the end and have that wedged in the vacuum housing on the back on the petcock. they were screwed up in a way that let fuel through in any position. which i think was flooding out the motor. i also charged the batt externally. either way it ran fine for about 20 miles. now its popping and cutting out like crazy. i haven had a chance to get too into that one yet. i think the carbs need a good cleaning.

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so now im not getting spark on the left side. nothing looks out of place under the points cover. while investigating this (with the key on to bump the starter) i noticed right side coil was hot. is that just because the key was on and the points were making contact sending juice to the coil and creating heat? i dont know i getting a little confused. is there certain voltages i can check for throughout the ignition to see where my problem is?

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so i decided to chop now and fix those issues later. here is the bike today.

020.jpg

i cut a little of the frame to invision the seat height and length

013.jpg

i am only 5-11 so im not too sure about the amount of strech. anyone have a comparison for me?

050.jpg

apes would be sweet huh.

051.jpg

i am still trying to decide on fabbing up my own hardtail or getting one from somewhere like tc brothers. what do you all think?

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so i decided to chop now and fix those issues later. here is the bike today.

020.jpg

i cut a little of the frame to invision the seat height and length

013.jpg

i am only 5-11 so im not too sure about the amount of strech. anyone have a comparison for me?

050.jpg

apes would be sweet huh.

051.jpg

i am still trying to decide on fabbing up my own hardtail or getting one from somewhere like tc brothers. what do you all think?

check over at thechopperunderground, theres several guys maybe even in your area for hardtails. on your motor issues , these bikes wont run right on a bad or weak battery, get a new battery and a good one, wallyworld batterys seem to be junk, charge it accordingly, trust me these bikes do wierd stuff on a bad battery.

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well you see i am wanting to run this bike kick only. i have read about someone running a capacitor in place of the batt. is that possible with a head/tail/brake set-up? is there a wiring diagram someone can post? if i do run a batt it will be new. thanks jeepurz

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well you see i am wanting to run this bike kick only. i have read about someone running a capacitor in place of the batt. is that possible with a head/tail/brake set-up? is there a wiring diagram someone can post? if i do run a batt it will be new. thanks jeepurz

your gonna need a battery, unless you swap out to a sparx unit, I still use a battery although you can go small size, both mine are kick only, huge weight loss and kickin is just a personal thing. Ill try to post a wiring diag after work. purty simple to wire.

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your gonna need a battery, unless you swap out to a sparx unit, I still use a battery although you can go small size, both mine are kick only, huge weight loss and kickin is just a personal thing. Ill try to post a wiring diag after work. purty simple to wire.

Jeepurz, i have read about some guys running a smaller sealed lead battery (7ah), but i dont know much about them. what is that sparx unit you mentioned? a wiring diagram would be a big help. i sure appreciate the info.

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try this guy, youll want the 3 phase. there pricey but it will end any charging woes you got . youll still want a small battery or your lights ect will drop with revs.

& heres a simple wiring diag.

1978CH_7E1.jpg

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  • 2 weeks later...

There are 2 brushes for the charging system under the side cover, they wear out, and it will cause exactly what you describe, most hard core 650 guys carry a spare set of brushes just in case, I fixed mine 1000 years ago on the side of the road, you cut the lead wire to the brush and wire it to the spring pushing on the brush, its very temporary but it got me home on a 3 hr one way ride.

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  • 2 weeks later...

well i have my universal hardtail kit from TC Bros now. i know how it is suposed to be put together, but i just dont want to be want my bike to look like everyone elses. so take a look and please leave me some feedback on which setup you like.

both are showing 4" of stretch. the forks are squatting down 2" via rachet strap. and as it sits in the pic it has 5.5" of ground clearance to the framerails. i am aiming for 4" of gc but this is the latest pic i have. more will be coming soon.

setup A

065.jpg

setup B

064.jpg

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  • 8 months later...
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