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Discussion Starter #1
I have upgraded to Dynatek coils as recommended on this forum, which has made incredible improvements to the starting, low rpm smoothness (1000 to 3000rpm) and made the bike more free reving above 5000 rpm as reported by everyone else who has done and recommended it thanks.

I also have decored mufflers (I know they are fully decored as you can shove a broom handle right through them).

The bike runs sweetly everywhere now except between 3000 and 4000 rpm where it feels pretty lumpy.

I really don't need anymore power but I would like it to drive thru the 3000 to 4000 rpm range smoothly - it would make it so much nicer to ride.

Is this normal - part of the natural character possibly?
Is this likely to be a fuelling issue? I have no idea if it needs to be or has been rejetted for the mufflers by the previous owner
Is there a cure?

Thanks for your suggestions.
 

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When you decored your mufflers you made the fuelling leaner, and it was lean to start with from the factory. So the bike will run poorly.

Solution is either a jet kit or (as many will chime in to recommend) a set of Keihin FCR41 flatslide carburettors.

I have the same issue (just put on a set of D&D carbon fibre mufflers) and I didn't want to invest $1K in carbs, so I bought a jet kit from ca-cycleworks. Once it's installed I'll post up the results.

Cheers

d.
 

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Discussion Starter #3
When you decored your mufflers you made the fuelling leaner, and it was lean to start with from the factory. So the bike will run poorly.

Solution is either a jet kit or (as many will chime in to recommend) a set of Keihin FCR41 flatslide carburettors.

I have the same issue (just put on a set of D&D carbon fibre mufflers) and I didn't want to invest $1K in carbs, so I bought a jet kit from ca-cycleworks. Once it's installed I'll post up the results.

Cheers

d.
Many thanks very keen to hear your results!
 

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Wobblyas:

I too am looking for all around smoothness. I am about to put on the Dyna Coils but I think I am also going to install new a new programmable ignition as well. I heard great things about the Silent Hektik monoblock (very expensive), but I think I am going to go for the Ignitech TCIP4 that CA Cycleworks sells for $200. Check out this thread, it has a lot of tweakability:

http://www.speedzilla.com/forums/general-ducati-chat/56146-ignitek-tcip4-amazing.html

The carbs do need to be jetted correctly still but I hear the ignition is another area that can stand upgrading on the 900ss.
 

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Rough running in the low to middle RPMs under steady throttle can be from rich or lean conditions. Based on your mods you clearly have a lean condition so you get some surging. On my FE I went with the stage II Dynojet. I have a BMC filter with open air box and Ferraci slipons. Good for 66ftlbs of torque and absolutely perfect carburation. The number one problem on rough funning 900s is out of synch carbs, so do that first, get the jet kit, and do it again. For some reasons the 900ss get out of synch quickly, I think it has to do with the solid alum manifolds transfering more vibration to the carbs. Hope that helps.:D
 

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Discussion Starter #6
Many thank Zoomy. I wouldn't be surprised if my problem is out of synch carburettors. Is synching the carburettors something I can do in my home owrkshop?
 

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You bet, to do it right you need a carb synchronizer, they run about $50, or you can make them using a number of methods which you can find over the internet. For a quick fix you can adjust one carb to the other by sound and feel. Basically turn the throttle body screw in and out seeking a smooth idle. hold the rpms up at about 3,000 and see if it smooths out. You can play around with it some. This last method is in no way ideal but if carbs are way out of synch you can make significant improvements. Whats nice is that you are only adjusting one carb to the other versus adjusting 3 carbs to the number two cylinder/carb on an inline four.
 

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potentiometre

Hello there
I had some problems when I took over a 2001 750SS i.e. I have overcome most by:

Power Commander for the 750SS
Changing from a stock airfilter to K&N,
Installing a potentiometre between the airtemp sensor.

The bike runs nice when on the border slightly sounding rough around 4500 to 5500. One twist on the potentiometre and it runs rounder, but not faster. When pulling the twist a little back it runs about 5 m/h faster.

When at full twist the spark plug is black, at half twist it stays brown. Not in all weather though, colder requiring a lesser or smaller twist.

regards
Arnego2
 

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Hello there
I had some problems when I took over a 2001 750SS i.e. I have overcome most by:

Power Commander for the 750SS
Changing from a stock airfilter to K&N,
Installing a potentiometre between the airtemp sensor.
Hmmm... can't get a PC for a pre-'99 SS and we don't have no fancy air temp sensors either :D

Might be good advice for fuel-injected bikes but doesn't apply to our bikes, thanks anyway though ;)

Cheers

d.
 

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When I got my '93 750SS it was bone stock, 6K miles and was almost unrideable at lower revs (2500~3500).

I did:
1. Stage II jetkit
2. K&N filter (no lid)
3. 14T front sprocket with stock 37T rear sprocket.
4. Conti pipes
5. New Champion plugs
6. New AGM battery

It now runs smooth and pulls good through the entire band and is a more "civilized" ride. Next task is to check the carb synchronization just to be sure.

Hope this helps!
 

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When I got my '93 750SS it was bone stock, 6K miles and was almost unrideable at lower revs (2500~3500).

I did:
1. Stage II jetkit
2. K&N filter (no lid)
3. 14T front sprocket with stock 37T rear sprocket.
4. Conti pipes
5. New Champion plugs
6. New AGM battery

It now runs smooth and pulls good through the entire band and is a more "civilized" ride. Next task is to check the carb synchronization just to be sure.

Hope this helps!
I've got the same setup except a 39T rear, have to say runs very nicely. I'd say check the fueling, maybe run it through a dyno with a sniffer to get real air/fuel readings.
 

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Discussion Starter #12
When I got my '93 750SS it was bone stock, 6K miles and was almost unrideable at lower revs (2500~3500).

I did:
1. Stage II jetkit
2. K&N filter (no lid)
3. 14T front sprocket with stock 37T rear sprocket.
4. Conti pipes
5. New Champion plugs
6. New AGM battery

It now runs smooth and pulls good through the entire band and is a more "civilized" ride. Next task is to check the carb synchronization just to be sure.

Hope this helps!
Thanks for the suggestions received so far. I am going to synch the carbs as suggested - Need to buy a carb balancer first - Suggestions for an effecitive budget one greatly accepted!

I have already upgraded to the Dynatek coils - has greatly improved and replaced the belts, changed the oil and fuel filters, cleaned the oil screen, fitted some bar end mirrors and reset the fork height and sag of front forks and rear shock with the advice/help on this forum already.

This work has already transfromed the bike significantly and I will do some further suspension upgrades when money available and it's more fun to do things in stages.

Mufflers were already decored when I got the bike and it was already fitted with a bigger rear sprocket.

Does changing the air filter really provide real gains or just make more noise?

If so is it possible to use the K&N or a BMC filter with the lid but with the snorkels removed? Would this give much improvement?

If you do use it without the lid is it necessary to modify the airbox in anyway to fit it? Does this give a noticeable improvement over just removing the snorkels?

Thanks in adavance. You can tell I am a newbie with all of these questions. Really appreciate the help I have already got from the very helpful/knowledgeable people on this Forum.
 
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