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Messages - Phil_Mart

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British Bikes / Re: Hello and Tiger 90 backfire problem.
« on: May 13, 2007, 06:03:54 PM »
Things have moved on!

Just to confirm the history of the bike, it was originally a 1958 3ta, then modded and re-registered in 1971 as a Tiger 90. It has now had the engine upgraded to a 500cc spec.

The carbs, Amal concentrics, were in a mess, different needle settings etc. One with no filter in the banjo, no filter on the tank tap and of course both full of debris. So they have now been fully stripped and cleaned out.

Then on a short run, with still the usual back fires from the left (when the throttle closed) the left side packed up all together. Investigation revealed a coil gone down. However, as the coil is a Duciller 12v twin coil unit I will have to replace the whole thing.

The ignition is a Boyer unit and as the compression ratio is 9.5 : 1 I'm tempted to follow Boyers advice and use two 6 volt coils in series. Unless that is someone knows better  ;)

Once the sun shines I'll try and get some photos posted to my photo site and get a link to em  :)

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British Bikes / Re: Hello and Tiger 90 backfire problem.
« on: May 08, 2007, 05:36:30 AM »
Hi,

Thanks for the reply.

I think its the Boyer ignition, but then as I've swapped the plug leads over and the problem remains I guess that rules out the ignition system then.

But then I've also swapped over the carbs and the problem remains. Soooo, its looking like an engine fault.

Apparently new valves springs and bronze guides have been fitted to the head. I'm wondering if the exhaust valve could be sticking?

3
British Bikes / Hello and Tiger 90 backfire problem.
« on: May 08, 2007, 02:54:33 AM »
Hi to all,

Been a longgggg time since I last had a bike (c70s).

Anyway I've just gone and got hold of an old, 71, Tiger 90. The chap I got it from has rebuilt the engine to 500cc but it has developed a nasty misfire on the right hand cylinder. Also I notice that on tick over that cylinder is running cooler than the left one.

The carbs are Amel concentrics, I've changed them over but the problem remains on the right side. I've swapped over the plug caps and the problem remains on the right side. This just proved that the twin coil unit, a Duciller, is Ok.

The bike is fitted with an electronic ignition unit, with a pick up housing replacing the distributor, my last 5ta had a standard distributor set up. Could it be that there's something wrong with this unit?

Any help or advice would be welcome.
TIA.

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