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Ian Brooks Member
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Hi all,newbie here. Bought my JH a month ago & she ran fine,however last week after firing her up sounded like she was running on 2 cylinders,so replaced plugs & wires to no avail,then pulled the distributor to find the vacuum advance piece was broken & un repairable & the iwires were looking a bit dodgy ,so ordered the petronix & flame thrower coil.Installed those & bypassed the resistor & gapped the plugs to 45,still to no avail.Pulled one of the carbs to find the real problem all along, a blocked main jet,so cleaned that & got it to run on all 4.However stiil wasnt running smooth like she did.Put a timing light on it to find it was way advanced so tried to retard it only to find the vacuum advance was hitting the block,so proceeded to loosen the timing belt taking care to keep belt tight on cam shaft gears.Finally was able to retard timing to 8 degrees,but she sounds terrible.Getting really frustrated now,pulled & cleaned plugs,leaned out carbs as plugs were sooty & smoke coming out of tail pipe.This is a rebuilt engine by the way or so I was told when purchased .did a compression test & she read 115-120 all the way across.] Not sure if this is a spark or fuel problem,any suggestion or clues would be greatly appreciated.Thanks in advance,Ian |
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Mitch Ware Member 
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A couple of things stand out, IIRC your plug gap should be 35 not 45. Also with pertronix timing should be 12^ advance. |
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John Kimbrough Member
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Ian, you might also want to try putting that balast resistor back in. I put in a pertronix, left the resistor in, and it is running fine. You might be shorting out somewhere because of too much spark. John. |
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Ian Brooks Member
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Thanks for the tips guys will advance the timing & reduce the gap.It definitely runs smoother the more advanced I go.Pulled the carbs & retightened them evenly as was sucking air somewhere ,it does,nt change rpms now when I squirt carb cleaner & that made a big difference.I still think I need to lean the mixture a little as the plugs are little sooty.Seem to be making progress though. Ian |
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