Visit our new website:

Trouble Shooting • 82 cb650sc cylinders 1 & 3 not firing

  • Tue, 13 Feb 2018 04:41
Their headers are cool at all RPMand plugs are wet.

I swapped the plugs and wires on each coil (1&4, 2&3) with no change ruling out those components and bad spark.

I DO have vac leaks at all boots but interesting thing I noticed is on 1&3, the trouble pair, carb spray makes engine rev and headers hot yay, but ironically the 'good' pair, 2&4 stall the engine with carb spray. I also swapped boots between the two pairs and they still behaved the same.

I dialectic greased all the connections except the ones with the shrink tube but they all looked really good.

I tried setting idle speed but 1&3 pilot scews aren't affecting the rpms at all, so I couldn't really finish that and adjustments overall didn't seem to make much difference, except with #4 which actually fires better than #2, bit hotter on the header and makes noise against my hand at the tail pipe, actually both 3&4, especially 4 pops on my hand whereas as 1&2 very slightly.

I had trouble with the timing as after searching the manual an online it still never became clear which mark is for timing, the T under the single mark or the F under the double mark? You might think T for timing but then the book shows the fixed mark lined up with the double marks over the F. So I just did the simpler "static" method. But I'd like to do the dynamic one with the light gun and do it right with the other advance something or other test. I'm new at this. Especially if it's more thorough. Tho the static method is easy and if it's accurate over a timing light I'll take it.

I did the valve clearances correctly but only after a lot of trial and error, so IDK if damaged the head. I would doubt it since I cant imagine setting the clearances on the lobes could cause anything make excessive contact with too much clearance so maybe less contact could mean more loose parts and shaky unstable movemet, idk, but I run it probably a few minutes after setting clearances incorrectly(it took me a while to learn how it all worked).

Sorry for all that but that's what it's been. So what do you think?

Statistics: Posted by juntjoo — Mon Feb 12, 2018 6:00 am

Total Motorcycle Forums


Harvard Business Review

Related Stories

Motonation Rapita Textile Mesh Gloves Meet The Desert: Hands On Review
  • Tue, 22 May 2018 16:34

My Criteria And Gloves Of Choice For me, touch is important. I like to have the ability to touch lightly with just a finger or two if I am moving my h...

KTM EXC Model Year 2019 Has Arrived
  • Tue, 22 May 2018 14:42

Following on from revolutionary model introductions in enduro in the last two years, KTM is proud to announce its refined and updated EXC model year 2...

Omnibion War brings Star Fox style shooting back to PC
  • Tue, 22 May 2018 12:53

A confession: I love on-rails shooters. At least, I did during the peak of the genre, when Panzer Dragoon, Star Fox 64 and their ilk briefly ruled the...

Yamaha and Workhorse Speed Shop Set Their Sights on Sultans of Sprint
  • Tue, 22 May 2018 10:36

Custom bike builder extraordinaire Brice Hennebert puts the Workhorse Speed Shop to the task of taking top honours in the Sultans of Sprint Factory cl...

MotoGP Le Mans: Petrucci marks Ducati’s card for factory seat
  • Tue, 22 May 2018 08:40

Petrucci believes it will come down to a choice between himself and Jack Miller for the second works Ducati MotoGP seat Bikesport News - News

Comment on Le Mans MotoGP Results (Uncategorized) by Anonymous
  • Tue, 22 May 2018 04:46

Marc is simply in a league of his own right now. It makes me wonder what someone like Dovisioso, or Vinales could do on the Honda. Even then, I feel l...

MotoGP Le Mans: Podium doesn’t mean problems are solved - Rossi
  • Tue, 22 May 2018 00:52

Rossi didn’t have the pace for a MotoGP podium at Le Mans and benefitted from Zarco and Dovizioso’s crashes… Bikesport News - News

The 6-Foot Chinese Giant Salamander Is in Serious Trouble
  • Mon, 21 May 2018 22:52

Scientists figured out one species is actually at least five. Which means conservationists have been going about trying to save the creature all wrong...

MotoGP Le Mans: Flawless Moto2 win for Bagnaia
  • Mon, 21 May 2018 13:11

No-one could lay a glove on Bagnaia as he rides to the Moto2 win at Le Mans Bikesport News - News

Texas school shooting: Arm teachers to stop gunmen, official says
  • Mon, 21 May 2018 11:27

"Four or five guns to one" could stop gunmen from killing students, he says after a school shooting. BBC News - World

Pakistani student killed in Texas HS shooting remembered
  • Mon, 21 May 2018 10:27

Hundreds attended a funeral service at a mosque in Stafford, Texas, to remember Sabika Sheikh, a Pakistani exchange student who was killed in Friday's...

MotoGP Le Mans: Marquez wins as Dovi, Zarco crash out
  • Mon, 21 May 2018 08:39

Marquez now has a massive points lead as he easily wins the Le Mans MotoGP round Bikesport News - News

News Categories