Some reason the closeer I get to riding the further back I end up. Bought a battery to help with lighting issues (hooking up lights but realized blowing bulbs some reason). Anyways, got bike running using electric start, was running, shut it off and now it won't start again with either electric or kick.
Turns over fine, getting fuel (plugs damp), getting spark and has plenty air flow. Has all basics to make it run but won't catch. She sounds like she wants to go but acts like something is "off"
Tried the following from reading forums around the web:
Disconnected ignition/kill switches (as will kick start and run without)
Disconnected any cables, etc we added that may cause faulty ground
Changed wire harness from parts bike (orig had splices)
Tried rectifier from parts bike (it works cause thought was a problem b4 but disconnected plug)
All 3 fuses are fine
Used knowledge from working on cars/trucks to fig out but it's not making sense. Made sure all connections tight and connected except lighting as was not connected b4.
Any help is appreciated as I'm out of ideas what is stopping me from riding. Getting really frustrated as I've waited a long time to get the bike style always wanted and I've hit a wall with ideas.
i've seen a lot of "old gas" being used recently,, and eveyone says,, it isn't that old!? but if it isn't fresh gas, try that,,, as it may foul the plugs,, other than that.. check your timing plate didn't move unexpectedly,, just a couple guesses
I know that it's fresh gas cause I put it in Saturday, same day the issue started. Did run low on fuel but once filled back up, ran b4 shutting off and now nuthing. As for the timing plate, is that behind the left cover (sitting on bike)??
Open gas cap and try to start, sometimes tank vent gets clogged up creating a vacuum, fuel doesn't flow as well. Also check oil level as well, these old bikes don't like to run on less than optimal oil level, at least thats my experience with my 72 cb500. GL
Did notice what seemed be a vacuum lock when opened gas cap, even filled but it didn't make any difference. I was looking around another forum and something came to mind. With the kill switch...is the motor still able to ge power to rotate or is it supposed to cut all power so that it does nothing at all. I know the theory is to stop the bike when running but when off, does it only cause the power not to flow to start or completely?
Ok, I was back looking over the bike again today for couple hours. Fully charged battery, 2 new spark plugs. Hooked up battery, changed plugs and proceeded see if would start. She REALLY wants to go but again something just isn't right. She coughed, sputtered and back fired out pipes with small red flames. More so out the left pipe than the right (sitting on bike).
These are the plug numbers I took out: NGK (R) DR8ES-L (the R was printed under NGK on plug)
These are the plugs I put in according to the CB400 Shop Manual: NGK D8EA
Now when I took old plugs out, they were black which tells me that was running rich. I put new plugs in gapped @ 0.026" (book says 0.024-0.028"). I tried starting again, spit, sputter, backfire, flames. Took new plugs out to inspect...left was black, slightly damp, right looked like was never ran, slightly damp as well. So, I plugged them into the coil and turned over to check spark. Spark looks bright blue and strong. If I ground socket of plug (where socket would go to remove), spark jumps to block as well as @ the electrode but seems strong.
I recorded a video as to what was doing but wasn't backfiring or shooting flames like was. Assuming because battery was getting low:
Was going to attach a sound clip file to demonstrate how sounded before issue having but won't let me do it. Hope video helps since I know seeing and hearing is better than just an explanation.
If there is anyone in the Brantford area that might be willing to give a hand, let me know. All help is greatly appreciated as this problem is driving me crazy.
Last edited by winterwolf; 04-09-2012 at 10:33 PM.
The R stands for "resistor"...you likely have resistor caps and resistor plugs. (Not right for an old CB.)
Take a look at your plug caps and see if they are resistor caps.
Change to the correct plugs. (D8EA) You can get them from CDN Tire.
It may not help but with too much resistance you end up with a weak spark.
(Fix the obvious problem first.)
Check your point gaps, they should be about 12-14thou. 12 will fire earlier, 14 may be too much, at least it is on my bike.
You can also static time your points with a voltage probe, and then once it is running time them properly with a timing light. It is all in the manual under the 3000 mile tuneup.
Reply With Quote
CB400 Bobber was running
Posting Permissions
Bookmarks