76 XS650 won't start after carb rebuild

[5twins]

How many miles on the points? If 10K or more, or if you don't know, they could be worn out and in need of replacement. In the mean time, you could open the points gap a little more. That will advance the timing and maybe put that right cylinder in time.

 

[Vivianthebarbarian]

Figured out my upload issue.

 

[jpdevol]

You're gain'in on it!

 

[Vivianthebarbarian]

PROGRESS! Charged up the battery and it started and ran today. I was able to take it up and down the road a few times. Dang this bike is fun! Parked it and came back about 30 minutes later and went to start it and after cranking a bit it started and ran for about 5 seconds and died. Then I couldn't get it started again. It seems like every time I have been able to start it, it has been just after charging the battery. I guess I need to check and make sure it is charging. I'm also still suspicious that the coils might be weak and lose performance when hot. Not sure how to test that before spending the money on new coils. Also whether to buy direct replacements off of ebay (Mike's has been out of stock for some time), or go for some kind of upgrade...but I don't want to spend the money on a boyer system, just want something that would work with my points.

 

[jpdevol]

You've mentioned the coils as a concern before. Not to downplay it, but what causes the suspicion?

I think you should reward your bike, and your hard work, with a new battery - perhaps an AGM style that may tolerate storage better. Maybe a battery-tender charger?

 

[Vivianthebarbarian]

You've mentioned the coils as a concern before. Not to downplay it, but what causes the suspicion?

I think you should reward your bike, and your hard work, with a new battery - perhaps an AGM style that may tolerate storage better. Maybe a battery-tender charger?

One of the coils was shorted out and was replaced with one from a parts bike. They were both tested at that time and had a resistance of about 5.3. I thought these coils were supposed to read about 4 ohms, so I thought they might be getting weak. Also have read accounts on this site where the bike would start up and run fine until hot then not want to run and in those cases it was the coils. This sort of corresponds to what has been happening with mine...so the suspicions. I may be totally off base in this and just fixating on the coils for no good reason...but not sure how to test to see if this is the problem other that replacing them. The battery was purchased new at the start of this project a few weeks ago. It is however just a flooded battery.

 

[Vivianthebarbarian]

Got it started again and checked the voltages. About 12.9-12.95 at idle and 13.3 v was the highest reading I got when reving it up. My book says it should be 14.5-15 v when at 2500 rpm, so I thought I'd test the voltage regulator. However my regulator seems to be different from the ones in my (Clymer) manual. The ones in the manual have green, brown and black wires. Mine has black, yellow and red wires in a multiple connector and a red with white stripe wire with a separate bullet connector. I can find other ones like this listed in connection with xs650's on ebay, so it seems like it is probably original equipment, but I don't know how to test it. Anyone know about this regulator and how to test it?

 

[jpdevol]

Me thinks you've come across the "Safety Relay". I don't have the electro-mechanical regulator, but I'll look it up. Your regulator should have the Br, Gn & Bk wires and offset mount holes.

 

[jpdevol]

Here ya go.........clean'em & set'em like the points

 

[Vivianthebarbarian]

Me thinks you've come across the "Safety Relay". I don't have the electro-mechanical regulator, but I'll look it up. Your regulator should have the Br, Gn & Bk wires and offset mount holes.

Ok, I guess I got the stupids. Looking at the wrong thing. Guess that's why the wires are wrong. Now if I can find the dang regulator. Thanks jpdeval.

 

[jpdevol]

Easy mistake - similar looking.

 

[jpdevol]

Try under right side cover?

 

[Kevin Werner]

Look at the pdf. In post #49 by @jpdevol. Set your core first then the gap with clean feeler gauge blades. Then adjust the output.

 

[Norton7d]

How about a picture(s) of the entire bike...love me some 76 models.

 

[Vivianthebarbarian]

Here ya go.........clean'em & set'em like the points

Thanks for this. Is it from a yamaha shop manual? It seems much better than the info from my clymer manual.

 

[jpdevol]

Yep; original factory manual '74-'77

emanualonline.com be careful to pick correct manual, they have Clymer, Haynes and others

 

[Vivianthebarbarian]

Try under right side cover?

Yeah, that's what I thought too, but ended up with the safety relay. It was under the left side cover for some reason. Pulled it out at 1 am last night and ran through the tests in my book and everything looks fine. I cleaned the points and am going to set the points gap and crank up the voltage adjuster a bit and see where that gets me. I've also been using a little wire brush (for a .22) to try and clean up all the wire connectors when I take stuff apart. Might as well.

 

[jpdevol]

Tedious stuff. If charging issues persist, maybe check and clean rotor brushes and rotor. While there check slip rings on rotor, should be 5+ Ohms between rings with brushes not in contact.

 

[Kevin Werner]

Tedious stuff. If charging issues persist, maybe check and clean rotor brushes and rotor. While there check slip rings on rotor, should be 5+ Ohms between rings with brushes not in contact.

Am I wrong to suggest you need to remove just 1 brush from the carrier to make that slip ring to slip ring resistance check?

 

[jpdevol]

Am I wrong to suggest you need to remove just 1 brush from the carrier to make that slip ring to slip ring resistance check?

Not wrong. I'm just keep'in it simple to aid any potential confusion