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**motoman** · 12-23-2012, 04:23 PM

Originally posted by BA80 View Post

I think I read something about this a while back but I can't seem to find it now.

This seems to be an ignition problem because of the symptoms.

I have RockinD's SG here and if you recall, we transferred everything from one frame to another.

When we parked it in the garage 2 or 3 weeks ago it was a lot warmer outside and it started just fine. I went out yesterday and decided to start it up and run it through a heat cycle because the rings are sticking from sitting before. I cranked and cranked and it wouldn't fire. Checked the spark and nothing. I figured it was because the battery may be low so I put the charger on it and cameback about an hour or so later. After a bit of cranking again It finally fired up but was not hitting on cylinders 2 and 3. After running for a few minutes it slowly began hitting on those 2 intermittently and then the problem just vanished.

It started fine the rest of the day, 2 - 3 times after.

This afternoon I tried it again. Same thing. No start for a bit then on 2 cylinders again until it had run for a while then the others kicked in again. I didn't put the charger on it today so I don't think it's a battery problem. The temperature seems to have something to do with it.

I've got a couple ideas but I thought I'd bounce it off ya'll and see if someone else had experienced this.

Yup.....sounds like a PRIMARY ignition issue as you stated Greg. Whatever voltage is at battery should be same elsewhere Key on, check voltage again at battery......still grounded at battery, check at top brown wire at fuse panel, then at brown wire comin' out of reg. Check voltages at both pri. coil wires with ign. on too.....bettin you'll find some low voltages at that last check point.

**BA80** · 12-23-2012, 04:30 PM

That's kinda what I was thinkin' but leaning more towards a bad ground. Damn powder coat caused a bunch of problems from the git go.

Doc changed about all the connectors on there too so that could be an issue also. I already had to fix a plug on the alternator because the tach kept dropping out.

**DGXSER** · 12-23-2012, 05:29 PM

Most likely coil issue due to the pairing. Just to be sure, are you certain you got all the float bowl jets clean?

**BA80** · 12-23-2012, 05:34 PM

Yeah, it's electrical. I was just out messing with it and I think it may be the stock fuse box. I was messing with the fuses while it was running and burnt my fingers. Bad connections between the tabs and fuses.

**oldyam80sg** · 12-23-2012, 07:13 PM

A lot of us have converted to the blade fuses and new fuse box.Will cure a bunch of issues.

**motoman** · 12-23-2012, 07:14 PM

Originally posted by BA80 View Post

Yeah, it's electrical. I was just out messing with it and I think it may be the stock fuse box. I was messing with the fuses while it was running and burnt my fingers. Bad connections between the tabs and fuses.

Yup, you got it right Greg. As you well know........always pri/sec. ign. before fueling issue. Carbs IS the LAST thing to suspect with this snenario, or any variation of it.....always, always. Sounds like your on the right trac. Get the honest 12v at those places, and double check at the pri.side of coils for same voltages just to be sure there are no ground sourcce issues.

**DGXSER** · 12-23-2012, 07:46 PM

The only thing that makes the carbs somewhat suspect is the fact it clears up as the engine warms up. Which is how fuel issue would act.

Yep, definitely fix the fuses first.

**BA80** · 12-23-2012, 08:03 PM

As I said in the first post it had no spark when it wouldn't start and 2 and 3 fired intermittently after it started until it had run for a while.

**skids** · 12-23-2012, 08:31 PM

Yep, sounds like a coil issue or a pick-up coil.

**BA80** · 12-23-2012, 08:48 PM

I don't think it will be the pick up coils because we found that the ones that were on his engine were bad when we were putting it together and swapped them out. And, once the problem clears up it runs great. It ran pretty much perfectly when it was warm outside.

I tend to agree with motoman. I think there's a voltage drop to the TCI due to a bad connection somewhere.

The wiring harness is kind of a mess because the bike it came off of had been on fire before and Doc repaired it. And as I said, the tabs in the fusebox got really hot when I was messing with the fuses earlier. That's where I'll start.

**motoman** · 12-23-2012, 11:28 PM

Originally posted by BA80 View Post

I don't think it will be the pick up coils because we found that the ones that were on his engine were bad when we were putting it together and swapped them out. And, once the problem clears up it runs great. It ran pretty much perfectly when it was warm outside.

I tend to agree with motoman. I think there's a voltage drop to the TCI due to a bad connection somewhere.

The wiring harness is kind of a mess because the bike it came off of had been on fire before and Doc repaired it. And as I said, the tabs in the fusebox got really hot when I was messing with the fuses earlier. That's where I'll start.

Your last paragraph brings up another suspect area, which may be a contributing factor. Not seeing bike, don't know where most of the heat would have been generated to, but look at the underside of the voltage reg. If that sealing black surface is no longer shiney and looks a bit cooked, the voltage reg. may show more of a low voltage than acceptable at idle, and a bit slow coming up as rpm's increase and at the top end of charge rate may be under 14v. I have a reg. like that that I had put on my bike a few years back to just test on bike and wound up leaving it on, but gradually it did exactly that, and just caught the problem recently. Removed it, putting my original reg. back on and voltages now hold at 12.2 at idle and comes up to 14.5 at around 2800-3000rpm. In other words, with all your circuit testing at idle, throw the test leads on the batt. at idle, see what you have. Helps to have an anolog tester in these cases looking for drops in voltages or erratic needle movements from from weak grounds. Digital volt meters can't follow those type of weak connections fast enough. I think maybe there is a combination of tiny electrical issues going on at lower warm-up rpms giving a bit of weak spark. I'd just go thru at this point if it will run at idle and hit those points I suggested earlier, might be surprised what you find. When you mentioned fire, the reg. came to mind since I have was on a bike that experienced the backfire out carbs, igniting the unknown fuel that had leaked into airbox. BTW, as I'm sure you know, any carb issue would be constant up to just before WOT, whether motor is hot or cold.

**BA80** · 12-24-2012, 08:14 AM

The thingn is when it finally starts its running on 1 and 4 until it starts intermittently hitting on 2 and 3 then it will idle fair but it still misses if you give it throttle all the way through WOT.

After about 5 minutes the problem disappears completely.

Here's the kicker that's going to make it tough to figure out. Last night I went out and started it up and made a short video with my phone to post on here and it was doing exactly as I describe. Well, I forgot to save the video to my phone so I went back out to re record it and the damn bike started and ran pefectly.

FRUSTRATING!!!!!

**TopCatGr58** · 12-24-2012, 10:05 AM

Hey Greg,

I've got the fuseblocks in stock ready for shipping! I had a couple with me at the XS Southeast rally, could have saved yourself the shipping fees!

T.C.

**BA80** · 12-24-2012, 10:17 AM

Thanks TC. I actually have one that I never installed here. Doc may end up with it for Christmas.

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