Author Topic: Glows in the dark  (Read 956 times)

Offline bsa-bill

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Glows in the dark
« on: 01.01. 2012 16:43 »
Saw something I don't recall seeing before but probably because I've not started a bike up in a confined shed in the dark before.
Decided the first of the month is a good date for a regular fire up through winter months.
First up the Flash, did'nt start as per usual (second kick) I think I hadn't tickled long enough so give it a definite flood and off it went, ran it for a while checking the lights - good - ammeter settled on middle with a few revs so switched lights off and noticed a amber glow from beneath the tank, fearing fire I peered down to see both ex pipes glowing cherry red, thinking about it the bikes running in a insulated shed full of storage boxes and no air circulating, I stopped the bike and fired up the RGF, first kick it roared into life stalled when I altered the choke a wee bit, flooded it again and first lick we are in business once more, checked the lights OK but does take a while longer on this bike for the charge to equalize, ran it for a while and noted the driveside pipe starting to glow but the timingside one never got to the glowing stage, larger shed with perhaps some more cooling air from the door at the timing side.
I have a meter with heat register so will check both sides for temp with the bike running outside.
Am i right to assume the glow is normal or does this indicate weak mixture
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

beezermacc

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Re: Glows in the dark
« Reply #1 on: 01.01. 2012 17:08 »
I've heard of sidevalves causing the pipes to glow as they do run very hot. I've ridden often enough in the dark with friends and not seen pipes glow on a twin though there may be something a bit unusual about your lighting conditions. From my experience the two most likely causes of excess heat on one side only are:- a) head gasket leak = weak mixture and b) contact breaker point imbalance. The latter is very common on twins due to the poor and inconsistent manufacturing of the cams and cam ring housings. The consequence of this is a variation in points gap (I've come across imbalances of 10 thou!), so it is very difficult to set the timing on both cylinders. Ultimately this leads to one cylinder running retarded ignition and getting much hotter than the other. I find A10's surprisingly sensitive to ignition timing inaccuracies. A friend of mine with an A10 recently seized both (yes, both!) exhaust valves/guides. The engine was obviously running hotter than it should and we traced this to retarded ignition. On a recent 600 mile run the bike ran faultlessly.

Offline bsa-bill

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Re: Glows in the dark
« Reply #2 on: 01.01. 2012 18:13 »
beezermacc  the RGF has electronic ignition, neither bike has shown any tendency to overheat when ridden, I'm thinking (hoping) that this is a result of running air cooled engines in a confined area with no airflow in almost dark conditions, just wondered if anyone could say they'd seen the same
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

beezermacc

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Re: Glows in the dark
« Reply #3 on: 01.01. 2012 18:20 »
Interesting, might be worth swapping the plugs over, checking the carb for tightness and having a look at the security of the exhaust pipes around the exhaust ports...always worth doing the easy things first. Only seen exhausts glowing in the dark on a sidevalve but have heard of it on rare occasions on other bikes. Have your exhausts gone blue?

Offline muskrat

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Re: Glows in the dark
« Reply #4 on: 01.01. 2012 19:23 »
 G'day Bill,
              how long were you running them? I warm all mine up for a good 5 minutes before taking outside and never seen that.
 I had all 4 pipes glowing to the collector box on the Rhonda Whore. 9000rpm, top gear (240kph) burn out. *eek*
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Offline bsa-bill

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Re: Glows in the dark
« Reply #5 on: 01.01. 2012 19:35 »
Hi Musky and beezermacc

I ran the bike long enough to put a carbfull through and my pipes are a beautiful  gold straw colour, I'm not over concerned about them glowing as there's never been any indication plug wise of leanness.

The RGF with it's alloy head did not get quite as glowing but is in a bigger shed, the one concern I would have is it getting hotter on one side.

as I said I have a meter with a temp probe so I'll have both bikes out in the open run them and compare temperatures , also in the back of my mind is could this be a stale fuel issue
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

beezermacc

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Re: Glows in the dark
« Reply #6 on: 01.01. 2012 20:24 »
Hi bsa-bill. The general concensus is that modern fuels burn longer causing elevated temperatures in the cylinder head and exhaust. I remember an article written by a classic car enthusiast making some very scientifically researched claims about excessive running temperatures. Because of the lower octane rating we have had to retard our ignition slightly as well (to prevent pinking) and this makes the temperature issue even worse! Stale fuel may certainly be adding to the problem but tha's easy to fix - I tip mine in the car. If your exhausts are straw coloured, my opinion (for what it's worth!) is that the running temperature is probably OK. I have two A10's with iron heads and two with alloy heads. The iron heads definitely get hotter than the alloys (not surprising). One side getting hotter than the other is a bit of a concern. I've made a few suggestions (plugs, head gasket leak, exhaust fit, contact breaker imbalance) in previous posts as to what might be causing this and would be interested in opinions from others on the forum.