Advice appreciated

[Fairview]

I thought that was the case , thanks Bryan.

The new filter turned up today, I fitted it, predictably it wasn't a perfect fit, the gas scavenging tube had to be shortened to get the filter to seal against the carb air intake. Anyway as soon as I rode up the drive I knew things were better, it had warmed up by the time I got off the lanes and on to a decent bit of tarmac and then the improvement was clear, it ripped up through the gears feeling and sounding like a new bike, I even stinked an unsuspecting Pan European. It's running perfectly now and I can't believe how well i goes or how easier a fix it was, things rarely go so easily for me!

Thanks again for all the advice,  ironically I don't think the painful throttle will be such a problem now it is actually responding.

Just a slipping clutch to sort now.

[florence]

If it slips a little under hard acceleration that is, I am afraid, rather hard to eliminate as they all do that a bit.  Some say different oils help.  I keep meaning to fit heavier clutch springs but never seem to get round to it as it means a new gasket etc and time.....

[Fairview]

Thanks Florence - it slips on quick revvy changes, I'd assumed it was worn plates or springs but haven't inspected it yet. I'm suprised to hear you say that they all are prone to a bit of hard revving slippage, I thought the clutches were supposed to be particularly good on the 550's? Are the heavier springs easy to source?

[LesterPiglet]

I got HD springs years ago but can't remember where. I have seen them online recently tho.

[Fairview]

Did they improve the clutch Lester?

[LesterPiglet]

I haven't had the bike running since I bought them..around ten years ago. 

[z1100r]

Agree with everything that has been said except "You have to have 2 cables". I agree with Lester on that one.
   On all my bikes that have 2 cables I have binned the 'close' cable. RD500's have them aswell.  I think the cable is predominantly for cold weather carb icing.

 I remember now how relieved i was  when I swapped my carbs way back in 82 to 550  to have a totally transformed throttle action. - from stiff and horible to light and nice. I even used a weedier spring than a stock 550.

 500-4 clutch and release mechanism is dreadful. As I think I said in my rebuild thread, The K3 was generally  a so much improved bike that its well worth fitting a K3 motor and carbs - if you are going to ride the bike alot. My original 500-4 motor and carbs are still sat on the floor untouched from 82. I knew I'd be riding the bike alot, so rideability was the priority not authenticity.

[matthewmosse]

The 500 cluch slips, think mine had H/d springs and was slightly better but it was fitted with a sidecar so was always going to slip a bit. 550 cluch could slip as badly if thrashed. 550K3 carbs are more fussy about being stood but give better economy. You'd be well advised to change the airbox rubbers if junking the rest of the 500 bits as I had choke cable routing issues with the k3 carbs combined with 500 airbox. K3 carbs and airbox are consequently a bit harder to squeeze in as the k3 rubbers are 10mm or so longer.

[Tomb]

I agree that they may have fitted the twin throttle cable for carb icing, however I can testify that it doesn't work, when I had my slides freeze there was no way you could move them either way, up or down, they were bloody solid

500/4 clutch mechanism? yep, shite

[z1100r]

The 500 cluch slips, think mine had H/d springs and was slightly better but it was fitted with a sidecar so was always going to slip a bit. 550 cluch could slip as badly if thrashed. 550K3 carbs are more fussy about being stood but give better economy. You'd be well advised to change the airbox rubbers if junking the rest of the 500 bits as I had choke cable routing issues with the k3 carbs combined with 500 airbox. K3 carbs and airbox are consequently a bit harder to squeeze in as the k3 rubbers are 10mm or so longer.

Agree, in terms of slipping, the K3 clutch was only slightly better. Choke cable and airbox were fine on mine though. I did swap the engine top cover I think, cant remember which one I used  500 or 550. Breather Pipe comes out at an angle on one and straight on the other. Guessing I used the one to match the carbs cable bracket.

 I actually found K3 carb rubbers considerably easier to fit.  a) because they are longer and b) the gap between carb and airbox is larger. My airbox is stock 500.

[matthewmosse]

I think I found the choke mechanisn hit the airbox unless 550 rubbers were used. The rest of the stuff aint too bad a fit, dont forget you'd need a choke cable brakett on the bars (bolts on). I think the 550k3 crabs are more prone to issues if stood though so a double edged sword, you get better economy but pay for it if the bike gets stood or cruddy fuel is used. 550 engine and 500 carbs run fine together without rejetting in any case. My next 550 related project once the sidecar is mot'd will be dropping a 650 top end on a 550 motor and adding a su carb in an attempt to get a bit more grunt and better economy.

[hairygit]

650 top end on a 550? You will find that it might be slower, the 650 had a slightly longer stroke as well as bigger bores, so you may end up with a lower compression ratio, and the camchain is a duplex on the 650. That said, many years ago a mate bored out his 550 to accept 750 pistons, but had to reduce the height of the crowns by trial and error, although if you measure from the top of the gudgeon pin hole to the crown of the 550 piston, and make the 750 piston the same, it should be okay (We were skint students back then, accurate measuring tools were out of the question ), but it did go very well!

[wizz]

my 550 f2 was running really rich and only doing about 30mpg the cure was a carb rebuild all the jets were knackered, fitted a carb rebuild kit to each carb