classic motorcycle forum

Motorcycle Discussions => British Bikes => Topic started by: Paulo on September 09, 2009, 08:36:44 PM

Title: D7 engine dies when throttle opened.
Post by: Paulo on September 09, 2009, 08:36:44 PM

My D7 now starts first time and ticks over ok, but when twist grip is opened full, the engine dies. This makes it impossible to ride.

It runs better when the strangler is on, so this leads me to believe i have a problem with the mixture.

 I have tried tuning the pilot air screw and the throttle stop but when i jump on and go for a ride the engine stops when i open the throttle.

could it be a air leak somewhere??

HELP!!

Title: Re: D7 engine dies when throttle opened.
Post by: harry on September 09, 2009, 09:39:07 PM

Hi Paulo, sorry to hear your news  from one extreme to another.First thing that comes to mind is the tank filler cap is the bleed hole clear to let the  air in the tank?.Also is the float sticking in the float chamber,? after the petrol has been on for a while rurn the tap off and then take the top off the float chamber to check the level; also check the needle is properly fixed to the throttle slideand that the petrol is flowing freely from the pipe at the float chamber end;/have you put petrol/oil in the tank since we last emailed? no chance of the oil being unmixed at the bottom of the tank?.I am running out of ideas now Think back and check everything you did to the engine since it was revving uncontrolled.Is the air filter filthy and restricting the mixture when the throttle is openedy?Finally check the ignition points, gap,and timing.Good luck  Harry.

Title: Re: D7 engine dies when throttle opened.
Post by: brooksy on September 10, 2009, 06:13:13 PM

Just a thought but have you checked the jets. I had a similar problem with a Greeves Challenger some years ago which turned out to be the wrong jets which flooded the engine.

I hope this is useful.

Good luck

Brooksy

Title: Re: D7 engine dies when throttle opened.
Post by: Paulo on September 10, 2009, 06:42:10 PM

Thanks Harry and Brooksy. A guy in work gave me a list of possibities and you have suggested exactly the same! Gonna work on it saturday.

thanks again

Paulo

Title: Re: D7 engine dies when throttle opened.
Post by: Paulo on September 17, 2009, 06:26:58 PM

Fixed it! the needle had become detached from the slide. running ok now, but the headlamp only works when on switched to 'e', not normal ignition. Is it a bad connection?

cheers

Paulo

Title: Re: D7 engine dies when throttle opened.
Post by: harry on September 20, 2009, 12:19:03 AM

Hi great to hear your news  if thepaulo,regarding the  electrics is this with the engine running?as far as I know the E place is for emergency start however I may be wrong never having had a Bantam{they were too new and expensive when I started motorcycling in 1948}.Now is your battery fully charged because if it is not the current is probably being directed to the light and to the battery when you switch to lights with just enough to run the plug.If the battery is OK then the rectifier may be failing{IT might be 50 years old in which case replace it with one of the modern ones which are much more efficient and can be bought at an autojumble for about £5.  It could be a bad connection  I would check all your earth connections and the snap connectors make sure they are clean inside another thought have you got the correct wattage bulb in the headlight.Good luck let me know what happens  Harry