On the Laverda Gt Sf we have the cylinder barrels pressed in. Green bk says they can slide out when turning up side down. Mine won't budge! Parker must mean later models. Is there a way to get these barrels out of Gt Sf w/ out going to a machine shop? I want to save $260...
cylinder barrel
- Thread starter Evan
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Ernesto
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- Location
- Hamburg, Germany
Put the cyl. in the oven upside down and supported, so that the liners
can slide out. But I don't know, which temperature is needed.
Ernesto
can slide out. But I don't know, which temperature is needed.
Ernesto
Last edited:
piranha-bro2
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- Location
- Melbourne
Think I just use 180-200 and have a block of wood handy in case they need a little help - they normally just drop out. Don't leave them in the oven too long or the cast liners expand as well - just long enough to get the alloy nice and how.
Ok I used the word barrel but it is liner. I see that in the manual. I'll try the oven @ 180 degress F for 5 minutes. I only need to replace one liner because it got chipped on top. Bought another good barrel yrs ago & have done nothing as of yet. Now replacing should be easy? The one liner sliding in will be cold...so w/ warm cyl & it should just slip right in? I have never done this before.
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GregT
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- Christchurch NZ
I'd assume you have to remove the new(er) liner from it's current barrel ? I'd also check the OD of the old one vs the replacement.
If it's up to say >001in bigger, fine, it's usable. But if it's smaller than the one you're replacing, think again. You do not want a loose cylinder liner...
Go for as big a temperature difference as possible when refitting the liner. I leave it in a deep-freezer overnight and only pull it out when I'm ready to reinsert it. 180 to 200F might be a tad low. 200C is around where I usually work when changing liners but I've not done a Laverda one so can't speak for their interference fits. It'll need more than 5 minutes too IMO.
If it's up to say >001in bigger, fine, it's usable. But if it's smaller than the one you're replacing, think again. You do not want a loose cylinder liner...
Go for as big a temperature difference as possible when refitting the liner. I leave it in a deep-freezer overnight and only pull it out when I'm ready to reinsert it. 180 to 200F might be a tad low. 200C is around where I usually work when changing liners but I've not done a Laverda one so can't speak for their interference fits. It'll need more than 5 minutes too IMO.
Tippie
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- Dr?bak, Norway
When it is up to temperature sometimes the liners will fall out in the oven, sometimes it needs a gentle tap with a bit of wood to dislodge it, have a bit of wood under to catch it. My experience with SF liners is that they don't have much interference fit. If you don't want the other liner to fall out you have to put some support under it. Are you sure you don't want to replace both and have it as new both sides when rebuilding?
breganzane
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- Location
- NSW Australia
So I've not done this myself, but apparently keep a little load on the new liner as the temps equalise. They can grab at the bottom and creep up a little at the top when fully cooled. Can play merry hell with head gaskets. Laverda is unusual in setting the sealing face a little below the mating face, and behind a lip at least on the 1000's. Check the height of the existing liner flange, it is probably 0.1 or so mm below the gasket face. Match that. Depth mic job.
this is how I drop liners, sit them on top of a fixture I made upside down, add 5kg weights to the top of the liner, heat them to 150-200C with a LPG Rose bud, they just fall out at some stage
if you only need to drop one liner use a stopper for the one staying in place as per 3rd photo
you cannot immediately reverse the process, let barrel cool down, clean everything especially the flange recess as best as possible, measure flange diameter and thickness, measure spigot depth and ID
Once confirmed it is the same, load liner into a freezer for a few hours, heat barrel to 180C minimum, drop liner in, add at least 10kg on top to stop the sucker from creeping up out of the barrel, it will
if you only need to drop one liner use a stopper for the one staying in place as per 3rd photo
you cannot immediately reverse the process, let barrel cool down, clean everything especially the flange recess as best as possible, measure flange diameter and thickness, measure spigot depth and ID
Once confirmed it is the same, load liner into a freezer for a few hours, heat barrel to 180C minimum, drop liner in, add at least 10kg on top to stop the sucker from creeping up out of the barrel, it will
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Love those weights Red.
Evan - My method for stopping the liners rising [as everything cools] is to get a medium weight copper mallet in each hand and do a bloody good impression of an excited Keith Moon on the top of the liners. No hitting violently of course, but 'purposefully', with the emphasis on fast and frequent - all around the 3 perimeters. The firm taps keep the creep at bay. Keep going for a long time. Naturally, the under-supports are on the bottom of the barrel casting and the liners are hanging down in fresh air. I use hard wood supports to avoid damage.
Evan - My method for stopping the liners rising [as everything cools] is to get a medium weight copper mallet in each hand and do a bloody good impression of an excited Keith Moon on the top of the liners. No hitting violently of course, but 'purposefully', with the emphasis on fast and frequent - all around the 3 perimeters. The firm taps keep the creep at bay. Keep going for a long time. Naturally, the under-supports are on the bottom of the barrel casting and the liners are hanging down in fresh air. I use hard wood supports to avoid damage.
CLEMTOG
Hero member
and be sure the spigot upstand is the same as the one you intend fitting, SFC eletronnica type are different for example, also a good idea to mark the liners and insert them at 90 degrees to their originally fitted position, but matters not of you are re-boring after fitment, where is the chip? it might not be vital to swap liners, and how many fins on the barrel, check that, they vary as well
CLE<
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GregT
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- Location
- Christchurch NZ
Yep, the LPG torch is how I do water cooled liners. they have noticeably less interference fit than finned aircooled cylinders. Couple of minutes warming and they drop right out.
Did a 2/stroke cylinder on my propane BBQ grill on a cold winters day when temp was -14°C, had the new liner in a jig next to the grill, slid the barrel over the liner and had about 10 seconds to align the ports before in locked in. Was surprised I had that much time...
I'm in the process of removing and installing some factory liners. Apart from being aware of the interference fit, there ought to be some other critical dimensions, ie dia. of top hat must match rebate and depth of liner vs cylinder block top face.
Since the block often gets skimmed flush, it's a ball ache to reset liner height.
What is the factory liner height ( negative protrusion) 1200?
Since the block often gets skimmed flush, it's a ball ache to reset liner height.
What is the factory liner height ( negative protrusion) 1200?
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Depends a bit on which type of gasket you'll be using, Rob.
The factory gaskets had a flame ring that was slightly thicker than the remainder, this corresponded with the slightly recessed (factory) liners. Gaskets generally available these days are flat all over and necessitate flat sealing surfaces, which is easy-peasy on a 1200, but no so much on a 1000.
Most cylinders by now have the liners slightly protruding due to innumerous heat cycles literally shrinking the alloy casting, leaving the top edge slightly proud. On 1200s, I tend to have the entire block skimmed to give a flat surface, this suits the "normal" aftermarket gaskets fine. With the 1000s, I remove the liners and machine them for a 0.1-0.15mm recess and fit one of Keith Nairns excellent new type head gaskets. These have the factroy-like thicker flame ring for reliable combustion chamber sealing. They also do away with the factory o-rings at the corners and have a silicon-type coating that eliminates the need for any extra sealing compound for peace of mind. The "normal" flat aftermarket gaskets can also be used on the 1000s if you can achieve a decently flat sealing surface, which unfortunately is a rare occurrance.
The big problem is that the material used for the flat gaskets won't compress after torquing the head. Protruding liners will seal the chambers nicely, but will prevent the head from placing enough pressure on the remainder of the gasket, causing oil leaks galore!
HTH,
piet
The factory gaskets had a flame ring that was slightly thicker than the remainder, this corresponded with the slightly recessed (factory) liners. Gaskets generally available these days are flat all over and necessitate flat sealing surfaces, which is easy-peasy on a 1200, but no so much on a 1000.
Most cylinders by now have the liners slightly protruding due to innumerous heat cycles literally shrinking the alloy casting, leaving the top edge slightly proud. On 1200s, I tend to have the entire block skimmed to give a flat surface, this suits the "normal" aftermarket gaskets fine. With the 1000s, I remove the liners and machine them for a 0.1-0.15mm recess and fit one of Keith Nairns excellent new type head gaskets. These have the factroy-like thicker flame ring for reliable combustion chamber sealing. They also do away with the factory o-rings at the corners and have a silicon-type coating that eliminates the need for any extra sealing compound for peace of mind. The "normal" flat aftermarket gaskets can also be used on the 1000s if you can achieve a decently flat sealing surface, which unfortunately is a rare occurrance.
The big problem is that the material used for the flat gaskets won't compress after torquing the head. Protruding liners will seal the chambers nicely, but will prevent the head from placing enough pressure on the remainder of the gasket, causing oil leaks galore!
HTH,
piet
Yup, those head gaskets of Keith's are the bizz .a lot of work went in to those, and the problems of a whole batch of bikes sucking in and burning oil , including mine, was properly sorted. It's somewhat upsetting to have a newly built motor smoking like a chimney...don't just fit anything old , or new, gasket!
Thanks Rob, see you in 25! The bike has newly fitted 4 pot brembos, behind the forks legs, yet to be fully tested but indications are good, and is shortly to have the slop taken out of the rear sets with Reds jewel like milled bushes..my daughter has just landed in Aus, and Red has kindly sent them to her boyfriend's mum in Perth...what we do for these old bikes?!would like you to try my Jota when we next meet..I think you might like it especially the engine,Happy Xmas
stevepm2011
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- Cologne, Germany
Well thought through and nicely made solution as usual
Regards from cold & dark Germany...I used to have 4 pots but half way through racing, I had to swap. Back to P08s, I remember now the 4 pots being more powerful but racing with the P08s wasn't too shabby either. Remember both were on the same 310mm discs not the 280mm and with 186 kgs.Thanks Rob, see you in 25! The bike has newly fitted 4 pot brembos, behind the forks legs, yet to be fully tested but indications are good, and is shortly to have the slop taken out of the rear sets with Reds jewel like milled bushes..my daughter has just landed in Aus, and Red has kindly sent them to her boyfriend's mum in Perth...what we do for these old bikes?!would like you to try my Jota when we next meet..I think you might like it especially the engine,Happy Xmas
On the road I'm sure they ( 4 pots) are a real benefit.
I'm honoured that you'd ask me to ride your bike, I've not ridden a Laverda since 2013 and what better way to get back in the saddle than on someone elses Lav
) .I should be on mine next Spring .
Your bike is getting better each time, good to have so many skilled suppliers and engineers fixing them.
Cheers