Lack of power 1991 FLHTC

I have just rejoined the fold after buying another Electra Glide, previous one had to be sold last year.
However, this one does not seem as quick. Engine seems ok, so I checked the carburettor and found that the slide does not move no matter how hard I rev it. Could this be a split diaphram? Or anything else?
I would like to fit an S&Sor should I stay with the stock item, any views?
Many thanks.

[DynaMik]

Hi Mal175,

You should be able to lift the slide with your finger.
If you can its probably the diapraghm, if you cant the slide may be siezed. Either way its gonna mean taking the top off the carb and having a peer.

Welcome back to HD joys.

Mik

[Ming the Merciless]

Lots of standard carbs are available for low bucks on ebay and elsewhere if you need a replacement.

IMO, a correctly set up standard carb is an excellent arrangement, suitable for most everyday situations. It's only worth replacing the carb with an S&S etc if you are likely to use serious extra performance and are prepared to pay the fuel price for this.

[kiwidave]

yep. the industry experts ALL agree......the standard carb is a good piece of kit. Most of the rest is just marketing budgets....

make sure the accelerator pump nozzle is squirting the jet of fuel STRAIGHT down the throat......many are off-cente....

also...have you considered this one may have different pulleys/gearing?

[Gray]

Originally Posted by mal175

I checked the carburettor and found that the slide does not move no matter how hard I rev it.

Explain how this works to me who's a bit dull, how does the engine rev without the slide moving?

[DynaMik]

The carb relys on the engine vacuum to lift the slide. When you open the throttle the butterfly in the carb body opens, this causes a vacuum from the pistons going up and down which lifts the slide thus allowing more fuel into the engine. If the diaphragm is split the vacuum cant lift the slide so no fuel to the engine. Its almost a self regulating system.

Many thanks for the replies.

I can lift the slide but it is heavily scored on one side.

The fuel is being jetted straight into the intake, so I am hoping it is just the diapraghm (hopefully spelled correctly)

So a carb rebuild tomorrow.

Still fancy an S&S though, I like the look.

[Phil]

Originally Posted by Gray

Explain how this works to me who's a bit dull, how does the engine rev without the slide moving?

The vacuum caused by the butterfly opening will suck enough fuel in allow it to rev, but very weakly & very lean. Unless there is a huge tear in the diaphragm rubber the slide will rise a little bit.

[grbrown]

Originally Posted by mal175

Many thanks for the replies.

I can lift the slide but it is heavily scored on one side.

The fuel is being jetted straight into the intake, so I am hoping it is just the diapraghm (hopefully spelled correctly)

So a carb rebuild tomorrow.

Still fancy an S&S though, I like the look.

Unless you make serious alterations to the engine I suggest you forget a change of carb. Rebuild your own, or buy a good secondhand one and fit a 'jet recalibration kit' from Custom Chrome (Dynajet is an alternative, although I was put off them) and Screamin' Eagle filter. Then regroup!

Thank you all for the help.
I stripped the carb and found the diaphragm was split, somebody had put a chrome carb top on it and caught it. I have replaced it and also the clutch which was slipping when I bought it.
Took it out on a run, an improvement put still feels very 'strangled', it does not respond like my previous FLH(standard). Air cleaner is clean, starts with no problems, was told it had been serviced prior to me purchasing it.
Silencers are very quiet and appear to be 2 left hand ones, down pipes are custom and do not join with each other as standard ones do. Would a change of silencer make a difference, apart from noise?