Friend just bought some sort of homebuilt thing and rode it straight over to mine as it stumbles around 3000 rpm...

Had a quick look:

- S&S Super E with .295 and 68 intermediate and main jets
- Short dragpipes with baffles
- electronic ignition of unknown origin
- Dyna coil and plugs

I fitted it with new plugs and set up the S&S as you do and it starts up fine when cold: enricher on and a few kicks (kickstart only!) and it starts and almost imediatly settles into a nice idle without the enricher on.

Runs fine and smoothly up 'till 3000 rpms and after that it stumbles and surges real bad.

Also, no matter how much I play with the acceleratorpump, it stumbles before it catches but the pump does work...

If you roll on real smooth from 3000 rpm's it will accelerate without stumbling...

Now to me that lot sounds like the main jet is way off, too small in fact?
If I rev it stationary it doesn't stumble around 3000 rpm's by the way, but that way it demands way less fuel.

Once hot it is also a PIG to start...

Anyone?

 

Check youtube for the S&S set up video. It will get you on the right track.

 

Thanks for that, I know how to set up the Super E though but for some reason this one doesn't seem to respond as it should, hence me asking on here.

I checked the jetting:

0.295 intermediate and .62 main so I've upped the main to .72 (smallest I had) and it's uterly unrideable now, low down as well...

Also when you rev it up quickly whilst stationary it stumbles as if the pump isn't working at all...but it is??

 

I hope I didn't offend you. I used that video to get a carb sorted on one of my old bikes.

 

What year and is it an Evo? Also what other mods were done. And where is your float level. sounds more like it's running out of fuel when it goes from the intermediate to main jet... something plugged maybe?

And when hot they don't need a lot of fuel. maybe just one pump from the accelrator.

 

Ifd you follow the S&S instructions, you will realize that the Exhaust system is Suspect...
If you follow Mintons Advice...you'll realize the Same thing...

 

Belated reply due to being in France, sorry!

Ofcourse you didn't offend me! Glad with all the help and suggestions I can get!

UPDATE:

It's a shovel, Dyna S ignition fitted and advance mechanism seems to work.

Carb is jetted to suit average Shovel but have tried other jets to see if it would change anything but it doesn't.

Starts fine, idles fine, when you rev it is stalls badly and in fact bangs and pops in the carbthroat (you can see the flashes as well if you take the filter off) as if the pump doesn't work (which it does), when you wind the throttle on very slowly it will pick up but still bang and pop.

If I strangle the carb with a cloth you can crack the throttle and it'll work as it should???

Battery is full and running 14.6 volts when running, static timing of the dyna is good, manifoldrubbers are new, coil is good (swapped it with a new one), sparkplugs new (tried to sets and different gaps).

WHAT.THE.HELL?!?!

The only thing I can now think of is that the ignition module is somehow faulty and when you crack the throttle and it needs to advance it doesn't do so properly, making it stall and bang in the manifold?

Could that be it?

Any help greatly appreciated because this one is really doing my head in, especially since it's kickstart only and it kicks like a mule...

 

Goede Dag.

Short open drag pipes are notoriously difficult to tune with a carb. Just for the hell of it, put some restriction in the pipes and try. Like a baffle, or the "lollypop" as the guys call it, or a large washer in at an angle.

Late model S&S Super E's have an additional opening in them that takes a jet like fitting and changes the crossover point between intermediate and main jets, from my understanding. If that is an early Super E, then you can fiddle with the hole size by enlarging it with a drill or reducing it with some solder. I would do some research on that before hacking it up.

The working when you roll it on real slow sounds like it is too lean at the transition point.

Also make sure the ignition has some advance/retard mechanism. Is it supposed to use the VOES? Does it have a VOES? Is it working if it is there?

Tot ziens.

 

Haha! Goedendag meneer!

It's not just a carbtuning issue I don't think now...

- Dragpipes with internal baffles
- Older Super E so no external airbleed
- Carb is clean
- Floatbowl is full

Ignition is a Dyna S item with a mechanical advance unit which moves freely, no VOES then.

Doing my nut in this one!!

Prettige dag!

 

Oh, when I take the plugs out there actually black and currently it runs a .295 slow and .80 main which should be too big for the application but I wanted to try something silly just to see if it would move the problem which is doesn't.

When I said it works as it should I ment that you can rev it without stalling but it still bangs and pops loudly, also on higher revs.

I've done more dragpipes and granted, hard to get right across the range but this is unrideable so can't imagine it will be the pipes really...?