Port inlet sleeves

RGM also seem to have the 500cc pistons in +20, +30, +40 and +60 oversizes listed - some of those weren't available last time I looked.

Incidentally - RGM don't mention the compression ratio (which of the two crown heights). Gandini do list them at both heights - but at +0.5, +1.0, +1.5mm. That's pretty nearly exactly +20, +40 and +60. Not much help if you are on +30. Also best part of 160 Eur EACH - not per pair - if their web site is to be believed.

I have just looked on the RGM site, and they are clearly marked as being sold by the pair. What I can't see is the fact that they are Gandini's. Where they list Hepolites they say so, but where not, they just say pistons. Also it is suggested on another thread that RGM state the piston weights. I can't see where they do that, either.

Sorry if we have hi-jacked your thread Anna. It is good news that the sleeves are available. They are hardly a wear item, so there must be a market to replace them when a PO has removed and binned them. My 650SS sleeves have been removed at some time in it's life. I would like to replace them, but I guess careful measurements need to be taken to ensure the ports haven't been opened out oversize by an enthusiastic PO, in the hope of gaining more power.

In your wisdom on these twins Anna (also calling Phil Hannam!) can you say why there are two types of sleeves, one with a notch and one without? They state the plain one is the earlier version, but engine numbers would be critical to know which fitted which. There must be a difference in the heads to require the notch?

Ian

Previously ian_cordes wrote:

I have just looked on the RGM site, and they are clearly marked as being sold by the pair. What I can't see is the fact that they are Gandini's. Where they list Hepolites they say so, but where not, they just say pistons. Also it is suggested on another thread that RGM state the piston weights. I can't see where they do that, either.

Sorry if we have hi-jacked your thread Anna. It is good news that the sleeves are available. They are hardly a wear item, so there must be a market to replace them when a PO has removed and binned them. My 650SS sleeves have been removed at some time in it's life. I would like to replace them, but I guess careful measurements need to be taken to ensure the ports haven't been opened out oversize by an enthusiastic PO, in the hope of gaining more power.

In your wisdom on these twins Anna (also calling Phil Hannam!) can you say why there are two types of sleeves, one with a notch and one without? They state the plain one is the earlier version, but engine numbers would be critical to know which fitted which. There must be a difference in the heads to require the notch?

Ian

Hi, Ian.

Just had a quick look at RGM's site and one set of the 650 pistons and whilst they don't give the make (they were Gandinis when I got mine a while back as previously stated recently) they do quote the weight when you click on the thumbnail after searching to go to the more detailed page. If you want to make sure you can always ring or email them to make certain.

Regarding the sleeves, I've always assumed that the notch was to allow the sleeves to fit without restricting the balance pipe hole. I've certainly fitted mine that way round.

Regards.

Hi Lance. I am just getting an enlarged picture when I click on the thumbnail. I am not yet at the stage of ordering new pistons, so would ask when that time comes. I would need to weigh the outgoing + 0.040" ones, but even so, the engine will not have been balanced with those in, so without knowing what weight of pistons it was balanced with, there is not much choice but to get it balanced anyway. I do know that, when ticking over on the centre stand without me on it, the bike 'walks' backwards with the vibration! Knowing what current wisdom is as to the correct balance factor would be good.

As for the balance pipes, mine had a single carb on when I bought it, so have no twin carb set-up to look at. One would have thought that the early SS models had a balance pipes, so how would they have got on without the notch? If it was necessary to drill the notchless sleeves back then, why bother to make that type now, one wonders?

Anna - the sleeves - I made a pair out of alloy. Never did a blind trial to see what effect they had. And of course I don't even know if mine are accurate. They start at the face of the head because the inlet track inside diameter within the head is bigger (1+1/8"?) than the 1+1/16" carburretors and spacers, so the tubes smooth away the step. The balance pipe (on mine anyway) is between the spacer blocks that carry the carbs, so is well outside the head and has nothing to do with the sleeves.

Ian - are you saying the sleeves run (ran?) all the way from the carb flange through the spacers to the inlet valve? I don't see how that could work without making the tract narrower than the 1+1/16" holes in the spacers.

It's quite a while since I last looked at them...

Previously anna jeannette Dixon wrote:

Hello good news New Port inlet sleeves for models 88ss and 99ss and 650 manxman and 650ss now available only At RGM Motors look on their new website.

hello Anna - As you and I both know the 99SS did not have the sleeves as it was part of the fittings with the semi-downdraught head. Regards, Howard

Previously David Cooper wrote:

Ian - are you saying the sleeves run (ran?) all the way from the carb flange through the spacers to the inlet valve? I don't see how that could work without making the tract narrower than the 1+1/16" holes in the spacers.

It's quite a while since I last looked at them...

Dave. I don't know. I am going on what Lance said in a previous post. Mine has a single carb and the sleeves were removed by a previous owner, so am trying to get to grips with how the original set-up was, and whether to revert mine to a pair of Monoblocs with sleeves. Hence I can't picture how there are 2 different sleeves on offer.

Later, '66- models, after Monoblocs were no longer made, were fitted with larger, 30mm Concentrics, so no doubt did not have the sleeves. One wonders why AMC made the change to larger carbs? Maybe I should fit Concentrics and not bother about the sleeves?

Ian