E: Engine Egli 500 Special Carburation

[Ben Langton]

Hello again everyone.
Some good news is I can now start the bike within a few kicks, sometimes first or second!
I took the advice of going back to standard specs on the carb pretty much.

Once started with choke, I turn the choke off and let it warm up, idles well. Now through acceleration getting up the gears all good as i pull up the hill by my house, as soon as i hit the level and part throttle its surging and jumping about. Now after moving the slide, trying slightly different jest I have moved this surging to about half throttle and a bit. It was lower. I cant get rid of it and the bike no longer likes flat out. I changed back a few steps and it seemed better flat out.

I think I need a tuner to look at it, its frustrating me now and I've exhausted my knoweldge and help from the forum. I see that a few mentioned timing and checking other things which is beyond me at the moment. I am keen to learn but need to take the bike to someone who can help, can any help or recomend someone. Im in Cornwall but have a van and want to sort this.

Many thanks for all the help so far, I feel I’m close just not got it right. The bike deserves to ride as good as it looks and id like to enjoy it.

 

[vibrac]

Stick it on a rolling road
Thats what we had to do with a Gardener carb and methanol we could have P***ed around for weeks otherwise

 

[davidd]

I could not agree with Vibrac more. Ask around and find a dyno shop that will charge by the hour for tuning. It will allow you to set the all of the carb adjustments as well as the timing. I have gone to a dyno shop and walked out with 7 bhp more than when I walked in. I cannot do that on my own.

David

 

[Bill Thomas]

I think the slide is too rich, Too small a cutaway, Once the plug has fouled it will upset it all through the range.
The other thing you may be able to alter is float level.
If you find someone with a dyno, You will need a set of jets and other slides.
Cheers Bill.

 

[Ben Langton]

Thanks very much.
I’ll look what is available locally, but I don’t think there is any. If anyone knows of anyone in the southwest that could do it for me I would be greatful.

Cheers

 

[Ben Langton]

I’ve found Hodges in Penzance and Biketuner in Plymouth. I’ll give them both a call and see what they say.

 

[davidd]

Ben,

That's a good start! Tell them you are racing and you need to dial in the tuning, so the dyno operator will be running the dyno for a time and then telling you to lower the float height. While you're lowering the float height or changing the jet or the slide, he can go off and do other things. I have found that shops who deal with racers will do this pretty routinely and they usually treat you well on the time.

David

 

[Normski]

When GT motorcycles were at Plymstock 10 or more years ago they had a dyno and a bloke called Steve to operate it who was very well spoken of. I think that shop was taken over by George Whites or some other big firm who then went bankrupt. I've looked up Biketuner at Plymouth on the web and they appear to be a similar set up and people as before George Whites.
Others have used Somerton engineering in Somerset and speak well of them. I intend to try them myself when time permits, but if in the meantime you try Biketuner in Plymouth I'd be glad to hear how you found them.

 

[oexing]

Ben,
I see your problem mainly carburation-related. You certainly will set ignition timing either suitable for twin sparks at below 30 degrees full advanced or around 34 degrees with one spark plug as on standard bikes. BUT apart from that I guess your Dellorto components will need a lot of tuning seeing that black spark plug - an indication for overly rich mixtures in various ranges of operation. Below is a link to a Dellorto manual plus link to a dealer showing what sort of fine tuning components are available for said ranges of operation depending on slide positions. Shipping to UK is € 10.50 in case . . . .
Basically I´d suggest using an O2 sensor for time saving and sparing you a lot of guesswork. For orientation in short: Idle is set by idle jet. -- 1/8 slide open look at slide cut out plus needle jet size -- 1/4 to 3/4 slide up is needle jet SIZE and needle SHAPE -- 3/4 to full is main jet and needle shape.
So depending on your findings get that sort of components for your particular problem zones. I´d first try a slide with more cut-out and a smaller needle jet. There are 20 different needles plus various needle jets so you will have to find out at what amount of slide aperture you like weaker or richer. The famous SU carbs are fine tuned with loads of needle shapes only, no slide variations there, no idle jets as well. So you get the idea . Flat out is about right you say, so ignition is not your biggest problem. Sorry I cannot tell any sizes of Dellorto components, hope a dealer may be helpful.

Vic
Dellorto manual

Dellorto components dealer

 

[greg brillus]

I found a lot of the dyno shops here wont look at old bikes with carburetors, even when I jokingly said to the chap at the counter that I could change jets, slides, idle mixtures and float levels probably faster than he could alter the settings on an injected modern, he laughed and said "Sorry........ Not interested".............