Hot starting

[Ian Watson]

Hello. I've always been able to start my Black Shadow cold on 1st or 2nd kick. Wonderful. But I continue to have difficulties when she is warm/hot. I realise some simply "have the knack". I know a little about finance but even less about ignitions etc. Do you think the BT-H magneto would help me ? Would it "increase my chances by 50%) !
Regards, Ian

 

[timetraveller]

If possible, borrow a coil ignition system from another owner and use that to see if it solves the problem. It is 'well known' that some original magnetos do not work well when either the windings or the capacitor are hot. If the coil system solves the problem then you have a choice of getting the present mag reconditoned, fitting a coil system or a BTH. If it does not then you have to look elsewhere. Good luck.

 

[Howard]

This sounds very much like the reason I changed to coil ignition. I bought the Vin with a reconditioned mag, and over 12 months it got harder to start when hot, then failed completely. We got home courtesy of the AA. I had the mag reconditioned by a well known expert (1970s) and all was fine, until it started to get harder to start when hot again, so I put coil ignition on and never looked back. I put Pazon on 2 years ago, and I’m even more impressed.

This is just my experience, as they say on the BBC “there are other makes of ignition available”.

H
ps One word of warning, coil ignition plus a bright headlight bulb needs a good charging system.

 

[Albervin]

Ian, what plugs are you using? When "hot" you should not need to use the choke or flood the carbs. A little throttle and a good kick. If that doesn't work then by all means upgrade or send the mag to Tim Thearle in Orange for a proper overhaul. Have had a BT-H for 6 years now and while it is not the perfect solution, it is very good.

 

[bmetcalf]

The bikes do vary. If my bike with mag doesn't start easily when hot, I wind the throttles full open and that "usually" does the trick.

 

[Monkeypants]

There are a number of electronic ignitions available besides the BTH self generated(no battery needed).
Pazon makes two ignition setups for the Vincent twin, a regular for single plug heads and a two plug head setup made for the Terry Prince two plug heads.
Francois Grosset has a very low power draw ignition for Vincents.
John Mcdougall uses Harley screaming eagle ignition in a housing of his own design. This is also a low draw electronic ignition with the advantage that should the ignition fail out on the road, parts are readily available at any Harley dealership.

Glen

 

[ClassicBiker]

Back when the Shadow was my father's he had a similar experience. Hard starting when hot, if it would at all. Had the mag seen to a expert across the river in Windsor. It didn't make any difference because he, the expert, didn't change the condensor/capacitor or rewind the armature either because he couldn't or didn't know how. Anyway when the Lucas RITA became available my mother and I bought it for my father for Xmas sometime between 1980 and 1982. Been happy since. About 12 years ago I had the mag rebuilt properly by an advertiser in MPH who replaced the capacitor and rewound the armature. Now that I've had it done I'll never need it.
Steven

 

[roy the mechanic]

Have you tried carburettor adjustments, before spending lots of money? My rapide will not start hot if the usual mixture adjustments (screw adjusters in+out to get the best idle) are made. It only starts hot if set rather rich. On mk 2 amals, no more than 1 1/4 turns out. Might be worth a try.

 

[BigEd]

How long have you had your Shadow? We tend to get to know our bikes and their "little foibles". Has it always done this or is it something that has gradually or suddenly started to happen? If you have checked that the carburettor settings have not altered then in my experience starting issues usually point to a breakdown in the quality of the ignition source. The difficult hot start is a classic conventional magneto capacitor failing symptom. Fiddling about with the points or cleaning plugs may improve the hot start. How much of the improvement is down to the magneto having time to cool down while you make adjustments is difficult to say.
If you intend to make good use of your Vincent and without discounting any of the good advice in the other posts I would look at a new or correctly refurbished ignition system to suit your preference or pocket. My own choice is a new BT-H that has given good service over the last three years/25,000 miles. If you have a good charging system then one of the electronic kits available may be an option or perhaps you know someone who can do a real rebuild of your original magneto.

As for increasing your chances of starting by 50%, a good spark will increase your chances 100% over no spark.;-)

Hello. I've always been able to start my Black Shadow cold on 1st or 2nd kick. Wonderful. But I continue to have difficulties when she is warm/hot. I realise some simply "have the knack". I know a little about finance but even less about ignitions etc. Do you think the BT-H magneto would help me ? Would it "increase my chances by 50%) !
Regards, Ian

 

[Howard]

Hi Ian.

If it is a capacitor problem this thread may be worth a look.

H


http://www.vincentownersclub.co.uk/showthread.php?4468-new-Magneto-Capacitor-fits-under-point