Forum

[Dean]

put my 350 back together after rebuild. checked timing gears for alignment. getting good spark, but won't start. all I get is the occaisional "ear splitting" backfire. the bike has a boyer ignition and power box. checked the wires to the ignition and they are properly connected. acts like the timing is really retarded, as when it backfires I get flames out of the exhaust. have tried moving the stator plate, but still no success. have suppressor plug cap and have tried various spark plugs. did note that the alternator wires were blue, yellow, red and orange. the orange and yellow match up with the wiring, but there are two purple wires left to connect to the blue and red out of the alternator - does it matter which purple wire goes to the blue and which goes to the red? should I pull the boyer off and try the original points? would hate to think that the boyer is the problem, as it cost a pretty penny.

[Dean]

took boyer off and reinstalled and still have same problem - getting spark, but bike won't start and only occaissionaly backfires.

[John R]

Where there's a backfire, there's hope. My first thought is, is your battery well charged up? Some Boyers, particularly older ones, are said to be intolerant of low voltages. Although the capacitor in the powerbox should compensate for this, I find that I need a well-charged battery to get a start. The wiring of the alternator is obviously important, but unlikely to affect starting. You could try putting the points back, but its a hassle. Boyers are mostly quite reliable; if you send them your ignition unit in the post, they will check it for you.

[John R]

Posts crossed there. Try 1) is there good compression? Your decompressor could be stuck open. 2) Try easy start or some other noxious ether based product. Quite often, when for some weird reason a newly assembled or not run for a long time engine won't start, Easy Start does the trick and you won't need it again. Who knows why?

[Dean]

going crazy. went out and hit the electric starter and it fired right up, but only ran for a few seconds. now the electric starter won't work and when I try to use it, I only get a clicking sound out of the electrics box. the battery is new. could this be an electrical problem and if so, how would it be tied to the electric starter? ( on prior attempts to start I had been kicking it over ) tried to kick it over and it goes back to the occaissional backfire.

[Alan R]

Hi DEAN----- you might want to try the exhaust cam timing again as it sounds to be opening too early OR}--------- have you re-timed the ignition on the wrong magnet ?

[Barry_Q]

Your problem certainly sounds electrical. The first port of call is the battery. Yours sounds like it's seen better days. I've had a similar problem before. What I did was to connect a car battery via a set of jump leads. Once the bike started, the jump leads were disconnected. The bike stopped. Both the bike battery and the rectifier-regulator were knackered. Once both were replaced, the bike (A Norton rotery) ran fine.

[Dean]

Alan - aligned the timing gears as per the manual when I put the engine back together. Battery is new as of today, as I thought that was the problem. What do mean by "wrong magnet"? Followed the boyer instructions and they didn't make any reference to a right or wrong magnet. Is the clicking in the electrics box a concern, as the electric start won't turn over.

[Dean]

turned key on and shorted from the battery to the starter and it started right up. Only ran for about 30 seconds and then died. So I can now assume that the battery is OK, my starter is OK, but something weird is going on electrically. Any ideas? Could it be some sort of relay between the battery and the electric starter? not up to speed on the electrics on this bike.

[Alan R]

Hi DEAN------ just refresh our memory as to the actual bike you have please--- it's a 350 with electric start you say ?? Have a look at this }--- http://www.ebay.co.uk/itm/TRIUMPH-T140- ... ts_13&hash ------------- is this the sort of Boyer you had fitted ??.. Yes, there IS a relay between the battery and the starter motor which looks like this }----- http://www.ebay.co.uk/itm/ROYAL-ENFIELD ... cycle_Part ----------------- If it's this that is "clicking" you could try shorting across its' main terminals with a large screwdriver blade but be careful as this will immediately activate the starter so make sure the ignition is turned OFF beforehand..... Remember that with either points or a Boyer system fitted they BOTH get their timing via the intermediate gear train...And as the backfiring is still there, regardless of which type that is fitted, then you need to be looking for a common factor...The gear train is one-----another is the HT coil------another is a power box, perhaps ??