About to bash my face into the wall with this starter issue.

[Gio_rosa16]

So, the other day I got my 78 special fired up and took it fr a few spins around the block to get this moving. After about 20 mins of riding and getting te motor warm, I turned it off to check out the carbs, but when I went to start it, it would not fire back up. I tried to give a little throttle to try to help it but when I gave it some throttle, it started making a weird knocking sound. Once again it ony made the sound when the throttle was engaged. I can't find any material on this issue and I'm going insane trying to figure out what it is. Any input would be great! Thanks everybody!! (Everything is stock)

 

[Rlauchard]

Check out gggGary's post... The 4th down here.

Knocking noise might be the wishbone shaped tension pin.

Is it starting?

 

[gggGary]

So it cranks over just fine but doesn't start? Then if you crack the throttle it knocks?
A loose cam chain will make a kind of a loud click, slap, klunk type of noise. What all have you done, checked so far on this bike? Did you pull the plugs, check spark, what did you see?

Did you try to kick start it? Does it still have the points ignition?
If you put the petcocks to prime do the carbs leak?

 

[Gio_rosa16]

It cranked over fine. Took it for a spin around the neighborhood, after I turned it off then decided to turn it back on the issue happened. After that, the knocking began but only when I opened the throttle during start. I did check the plugs even though the plugs and wires are recently new (past month). Plugs and wires looked good. I tried kick starting it but couldn't get to fire but I believe that's another issue. PO said it worked but of course when I got it home it did not. (Possibly clutch issue?) I have not checked the ignition to see if its still points. The carbs did not leak but I just got two carb rebuild kits just in case. From what I've read it sounds like it may be the cam chain. Any thoughts or ideas on what I need to do would be great! Thanks for all the help

 

[XSLeo]

I have yet to see an XS650 that liked any throttle at start up. Once it fires up then add throttle.
Does it still have the stock fuse box? If so the clips that hold the fuses aren't. The clips get weak and loose good contact. Swapping the fuse box for inline fuse holders that use modern blade style fuses is a great up grade.
Check for spark at the plugs. No spark=no star.
Do you have a repair manual? Follow the manuals to do a tune up.
Start by
#1 adjusting the cam chain tension
#2 adjusting the valves
#3 check points gap
#4 check points timing
With all of these adjusted right the only thing left is carbs, www.amckayltd.com/carbguide.pdf
As far as using the elcetric or kick start it will start better on the kick. It don't draw anything from the battery so the ignition gets full battery power.
Leo

 

[Gio_rosa16]

Thanks for advice Leo! I do have a clymer's manual that I just got a day or two ago. Do you have any places or shops you recommend where I can pick up inline fuse holders? I never thought of looking at the fuses. Now when it comes to kick start it. It won't even crank. Would that be a clutch adjustment issue? I know it's a different issue but hell might as well get the questions I got out while they're still fresh.

 

[gggGary]

Yes the kick start acts through the clutch. Kick start 101 the bike has to be in neutral with the clutch out. You have to figure on going through everything. One step at a time and setting adjusting etc. Most of the issues go away with adjustments. Any points ignition is just so so even at it's best. Did you charge up the battery? Once you get the engine going again check to see if your charging system is working. A pamco ignition will improve starting but for now dry the plugs with a propane torch, check spark and re-install, see how it goes then.

 

[XSLeo]

I like to ones from Radio Shack, they have a cover on them, not weather tight but a cover. Cheaper than the parts stores.
When you do the replacement, do one set of wires at a time. That way you are not getting them mixed up. I solder and use heat shrink tubing, two layers.
The clutch adjustment procedure in the Cllymer is good, just spin the adjuster screw in and out a few times to get a good feel for how hard it turns. This makes it easier to tell the point you first feel resitance. Then at that point back it off 1/8 turn instead of the books 1/4 turn. Page 24. lube the cable as the book callls forpage 10, control cables, use the oil method, works much better than the spray lube method.
Leo

 

[Gio_rosa16]

Gary- I did charge the battery, and after 20 mins of riding, it was struggling to start. S I'm thinking in investing on a pamco ignition. Thanks for the tips!

Leo- ill definitely look into radio shack for the inline fuse holders. Is there any particular part no. you used? If not, I will definitely look for one. I have quite a bit of parts I need to buy from radio shack. Thanks for the adjustment tip. I will definitely follow the clymer's for everything else. Thanks for all the help!

 

[retiredgentleman]

Gary- I did charge the battery, and after 20 mins of riding, it was struggling to start. S I'm thinking in investing on a pamco ignition. Thanks for the tips!

Leo- ill definitely look into radio shack for the inline fuse holders. Is there any particular part no. you used? If not, I will definitely look for one. I have quite a bit of parts I need to buy from radio shack. Thanks for the adjustment tip. I will definitely follow the clymer's for everything else. Thanks for all the help!

You have a worn out battery, and/or the charging system is not producing a high enough voltage. Check brush length is greater than 3/8". When you rev up the engine to 3000 rpm you should be getting 14.1 volts.................use a VOM to measure.

 

[Gio_rosa16]

Gentleman- I'm thinking the charging system is the culprit. As Gary said earlier, it'll be wise to invest in a pamco ignition. I have also looked into a permanent magnet alternator, but I will look at the brush lengths to make sure they are the proper length. Thanks for the tip!

 

[retiredgentleman]

Gentleman- I'm thinking the charging system is the culprit. As Gary said earlier, it'll be wise to invest in a pamco ignition. I have also looked into a permanent magnet alternator, but I will look at the brush lengths to make sure they are the proper length. Thanks for the tip!

As Gary mentioned previously, you repair these bikes, one step at a time. You likely have 4 or 5 areas to correct. You don't want to start buying parts such as a Pamco or a PMA , in hopes that they will magically solve all your problems. Fix the bike, the way it stands first................points ignition, stock alternator, etc.

The first area to get working is the bikes voltage supply, because its fundamental to all the other systems. You must have a good battery that holds its charge. The charging system must put out 14 to 14.3 volts at 3000 rpm. Once you have a good voltage supply, the voltage must get delivered to the bike's loads.................that means getting rid of those original glass type fuse holders, as someone mentioned already.

Don't try to use 35 year old points and condensers. Buy new ones. Those original stock ignition coils may give spark, but it will be a weak spark. The points ignition system will work fine, but you will have a much stronger spark, if you replace the 2 stock coils with 1 dual output ignition coil. That would increase the spark voltage from 12K to about 30K or more.