throttle slides past it?

olly

Senior member
Hi,
I'm having problems getting my SF1 to run at low revs.  The choke is needed at anything under about 2,000 RPM
Not had the carbs apart yet but please take a look at these slides.....do we reckon they're past it or will I still be able to get it running smooth enough with the wear?



P.S. What's the threaded bit for (the biggest hole you can see in this pic)?



 
olly said:
Hi,
I'm having problems getting my SF1 to run at low revs. The choke is needed at anything under about 2,000 RPM
Not had the carbs apart yet but please take a look at these slides.....do we reckon they're past it or will I still be able to get it running smooth enough with the wear?

No wonder, only place where those slides will feel at home is in the scrap bin... and chuck the needles and needle jets in there as well.

Inspect float valves for wear, jets for corrosion.  Check/adjust float heights, check accelerator pump membrane for suppleness, replace if stiff and hard (not always a good thing :D).

Should get your carbs back to satisfactory condition.  Eventually, the body too will be worn beyond service, time for new carbs...

piet

 
I would try to clean the carbs first, with a ultrasonic cleaner. Did mine this winter. My slides looks nearly the same and I have no problem at low rews.
Could it be some bad idle jets?
If still bad running, follow Piets advice.
 
haakeik said:
I would try to clean the carbs first, with a ultrasonic cleaner. Did mine this winter. My slides looks nearly the same and I have no problem at low rews.
Could it be some bad idle jets?
If still bad running, follow Piets advice.

Really don't understand...

When restoring bikes, owners are quite comfortable on spending hundreds and thousands on chrome and paint, thousands are sunk into the engine, many hundreds go into renovating the wheels and chassis.  No chains, brakes or tyres can be good expensive enough.  More often than not, the carbs (gearbox and clutch are likely candidates as well) are forgotten... I see it so often it no longer surprises me.

All it takes is a couple of gasket sets, a pair of slides, a handfull of brassware and an hour of patience at the workbench to return them to satisfactory working condition, usually less than 100 bucks for a single linkage-less carb.  There's more to carb maintenance than cleaning the body and polishing the float bowl... ::)

Carbs and their individual components should be regarded as consumables, just as chains and tyres.  Using worn carbs will only wear them out even further and quicker still, raise fuel consumption to astronomic levels and generally result in steadily deteriorating engine performance, often not noticed by the rider because it happens so slowly.

Ollys' slides belong in the scrap bin, and, judging by the slides, I suspect quite a few other bits inside his carbs as well. Corrosion and wear is quite evident on the needles alone!

New slides and other internals will not restore Ollys' carbs to 100%, but will be an enormous improvement over what he has now.  The alternative is to replace them completely with NEW instruments.

piet

 
Piet,

Wise words  ;)

I think Olly is in the UK. If so, I thing many are scared off by Dellorto UK prices. New slides, needles, jets, gaskets, floats, float needles, choke plungers would probably cost the best part of ?140 per carb  :o. This tends to put people off, as it is only the basics.

Olly, Grant put me onto Stein Dinse in Germany - much cheaper and great service. They even charge LESS to ship to UK addresses than Dellorto UK !!!

http://www.stein-dinse.biz/Dellorto:::15.html

Pete

 
Pete,

Thing is, even when working on a tight budget, overhauling a carb or 2 isn't going to break the bank.  Not every single component need be replaced.  It is easier though, knowing everything is new and spotless gives peace of mind as well.  Carefull inspection of the cleaned components reveals if they are fit for further service, the same as with any other old bike component really.  In my experience, needles and needle jets, or atomisers if you wish, are an absolute must, closely followed by pump membranes and float valves.  If the main, idle, choke and pump jets/valves are not corroded and show no signs of having been tampered with, they can be re-used.  Slides can work OK with a bit of wear, but when heavily worn, they will further damage the carb body, bringing replacement time of the complete carb ever closer.  I admit, a new slide will up the bill considerably, but the benefits can be felt.  Considering the average annual mileage most of our bikes cover, it will last for quite some time!

Clapped out Dellortos can be brought back to a surprising level, not everybody wishes to swap to modern flatslide Mikkies.  They do tend to look rather out of place, especially on a GT or S. 

I use Stein-Dinse too, availabilty is sometimes a bit of a problem... well stocked for PHB/PHF, but sought-after VHB bits are rare there too.

piet
 
Piet,

Yep. Agree it is well worth doing, but it is expensive. Andy supplied and shipped a cam chain, rear chain and primary chain for less than the cost of one set of carb parts.

It is possible to get carb parts a bit cheaper - With some research on the web and some help from here, I was able to find parts at an affordable price.

The Wasp price for jets was particularly cheap and they are the real deal, not pattern jets.

http://www.laverdaforum.com/forum/index.php?topic=87924.0

Pete
 
I agree entirely with Piet. The slides should be replaced and the carbs totally renovated..
I also agree with H?kon, if Olly?s bike is not idling and needs the choke at anything under 2000rpm, it is not those slides that are the problem.
 
sfcpiet said:
handfull of brassware and an hour of patience at the workbench

only an hour  :o
I need to trade my Dellorto expert in, he is slowing down  :D

 
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