Mugello 240 ??

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wintermod65
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Mon Dec 02, 2019 8:54 pm

hi,

has anyone converted the most up to date version of the Mugello 225 kit into 240 cc or is this possible at all

i currently have a GT 240 , but have not been impressed with it due to heat seizures problems and am considering different options.

most cost effective for me is to replace cylinder /piston/head

which would leave me with the 62mm crank that came with the GT kit.

guess ill need packers so looking for help to point but any other issues i might have in achieving this .

cheers

Scooterdude
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Mon Dec 02, 2019 9:46 pm

Yes you could retain your existing crank and use the 70mm Mugello cylinder to get you to 240 cc or why not look at the RT kit which is cheaper than the Mugello. If it were me and for all round cheapness I’d be looking at a Rapido cylinder, head and piston.

Remember your GT crank comes with an 18mm small end eye so to use any of the above kits you would have to buy the 18-16 step down small end bearing to use with their respective pistons.

Adam_Winstone
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Mon Dec 02, 2019 10:22 pm

I use Mugellos, as well as Avanti and others but know others that use GT kits with zero reliability issues. Be wary of swapping one kit for another if the problem is elsewhere, otherwise you may well find the next kit does exactly the same.

paul d
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Tue Dec 03, 2019 1:23 pm

I have no knowledge of mugellos but I do run a gt240 on a gt casing. Did you have your seizure problems while running in? I’ve 10000 ish miles on mine and it’s been great but without a temp guage I’d have blown it sky high during the break in miles! For the first 500 odd miles it ran very hot when trundling along in 4th below 50mph. A drop to third gear always dropped the temp. When it reached 145-150 I’d gear up again, up to 195c and I’d drop to third again. With the miles the general running temperatures dropped. Difficult on the nerves revving a fresh engine but it worked. Hope this gives some hope.

Warkton Tornado No.1
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Wed Dec 04, 2019 12:58 pm

I can well imagine there being problems with such a large bore all cast iron cylinder.

I possess Mugellos & Rapido amongst other cylinders, but would suggest that the Rapido is a very good cylinder to opt for if you do swap.

The longer stroke that you would maintain is an ideal opportunity to optimise the port timing. In addition, Suzuki TS250 pistons are available for a very reasonable price & will slot straight in. Just be aware that the piston/bore clearance needs checking as Rapido's can be very tight.......

The Rapido can be made very civilised & torquey, all the more so when used with a good carburettor & exhaust. By "good carburettor" I mean the sort better suited to a two stroke that has inbuilt anti-flood measures when fitted with an adequate filter, so that's any Lambretta derived hoses or filters out.......

I have to say that the PWK type have impressed me with their value & ease of set up. I have fettled a Lambretta engine recently that is fitted with a 30 mm PWK, but it worked just as well with a 34 mm which many would consider oversize.

(That 34 mm PWK will be fitted to my own Rapido (70.5 x 61) when time allows, complete with my own design of adjustable power jet)

wintermod65
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Mon Dec 09, 2019 9:29 pm

paul d wrote:
Tue Dec 03, 2019 1:23 pm
I have no knowledge of mugellos but I do run a gt240 on a gt casing. Did you have your seizure problems while running in? I’ve 10000 ish miles on mine and it’s been great but without a temp guage I’d have blown it sky high during the break in miles! For the first 500 odd miles it ran very hot when trundling along in 4th below 50mph. A drop to third gear always dropped the temp. When it reached 145-150 I’d gear up again, up to 195c and I’d drop to third again. With the miles the general running temperatures dropped. Difficult on the nerves revving a fresh engine but it worked. Hope this gives some hope.
hi .
yes i did have seize probs running in first one was after about a mile trundling at 30 mph then periodically if running about 45mph then encountered a hill , or any slight gradient
mine ran about 148 c according to sip speedo temp probe under sparkplug . plug was black so running rich somewhere in range changed up to a 8 as had a 7 in from build
it was worse on way home from brighton as almost 1000 miles done but was still hot into evening crawled back at 40 mph slip streaming our micro caravan after heat seizure nr gatwick agree nervous bloody wreck when got home speedo coming on an off didnt help ( ditched it in favour of smiths conversion now )as was glued to the temp otherwise , its now back over scooter shop who fitted the kit . but just wanted a plan "B" if it was the kit at fault

wintermod65
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Mon Dec 09, 2019 9:41 pm

Warkton Tornado No.1 wrote:
Wed Dec 04, 2019 12:58 pm
I can well imagine there being problems with such a large bore all cast iron cylinder.

I possess Mugellos & Rapido amongst other cylinders, but would suggest that the Rapido is a very good cylinder to opt for if you do swap.

The longer stroke that you would maintain is an ideal opportunity to optimise the port timing. In addition, Suzuki TS250 pistons are available for a very reasonable price & will slot straight in. Just be aware that the piston/bore clearance needs checking as Rapido's can be very tight.......

The Rapido can be made very civilised & torquey, all the more so when used with a good carburettor & exhaust. By "good carburettor" I mean the sort better suited to a two stroke that has inbuilt anti-flood measures when fitted with an adequate filter, so that's any Lambretta derived hoses or filters out.......

I have to say that the PWK type have impressed me with their value & ease of set up. I have fettled a Lambretta engine recently that is fitted with a 30 mm PWK, but it worked just as well with a 34 mm which many would consider oversize.

(That 34 mm PWK will be fitted to my own Rapido (70.5 x 61) when time allows, complete with my own design of adjustable power jet)

Think the GT 240 cylinder uses a TS250 based piston as well also , im a returnee to Lambrettas bought it in 2014 and finally on road this march so ive no experience in any of the kits that came out after the TS1 200 fitted to my GP back in '91 just hear positive things about the Mugello kit from various people chap in our club just had a 225 version fitted and rates it as well seen them around the £425-50 mark which isnt so bad i discounted 2 other 225 kits as they seemed to have problems plating coming off or ring pegs falling out so didnt want to exchange one set of issues for another

wintermod65
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Mon Dec 09, 2019 9:42 pm

Scooterdude wrote:
Mon Dec 02, 2019 9:46 pm
Yes you could retain your existing crank and use the 70mm Mugello cylinder to get you to 240 cc or why not look at the RT kit which is cheaper than the Mugello. If it were me and for all round cheapness I’d be looking at a Rapido cylinder, head and piston.

Remember your GT crank comes with an 18mm small end eye so to use any of the above kits you would have to buy the 18-16 step down small end bearing to use with their respective pistons.
oh good point cheers for reminding me of that

Warkton Tornado No.1
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Tue Dec 10, 2019 1:08 pm

wintermod65 wrote:
Mon Dec 09, 2019 9:41 pm
Warkton Tornado No.1 wrote:
Wed Dec 04, 2019 12:58 pm
I can well imagine there being problems with such a large bore all cast iron cylinder.

I possess Mugellos & Rapido amongst other cylinders, but would suggest that the Rapido is a very good cylinder to opt for if you do swap.

The longer stroke that you would maintain is an ideal opportunity to optimise the port timing. In addition, Suzuki TS250 pistons are available for a very reasonable price & will slot straight in. Just be aware that the piston/bore clearance needs checking as Rapido's can be very tight.......

The Rapido can be made very civilised & torquey, all the more so when used with a good carburettor & exhaust. By "good carburettor" I mean the sort better suited to a two stroke that has inbuilt anti-flood measures when fitted with an adequate filter, so that's any Lambretta derived hoses or filters out.......

I have to say that the PWK type have impressed me with their value & ease of set up. I have fettled a Lambretta engine recently that is fitted with a 30 mm PWK, but it worked just as well with a 34 mm which many would consider oversize.

(That 34 mm PWK will be fitted to my own Rapido (70.5 x 61) when time allows, complete with my own design of adjustable power jet)

Think the GT 240 cylinder uses a TS250 based piston as well also , im a returnee to Lambrettas bought it in 2014 and finally on road this march so ive no experience in any of the kits that came out after the TS1 200 fitted to my GP back in '91 just hear positive things about the Mugello kit from various people chap in our club just had a 225 version fitted and rates it as well seen them around the £425-50 mark which isnt so bad i discounted 2 other 225 kits as they seemed to have problems plating coming off or ring pegs falling out so didnt want to exchange one set of issues for another
There is very little to choose between the Mugello & Rapido in performance terms, when set up properly or even 'optimised' further by somebody that knows what they are doing. Where the Mugello does really come into it's own is on track, with it's heat shedding capability & Nikasil bore.

However, on the road there are advantages to be gained with having the Rapido with it's cast iron bore which is more durable in the event of a seizure.

I would not suggest such an option but for the fact that your existing long stroke crank can be made to work very well with the Rapido. Once again, though, it needs somebody that knows what they are doing. If it were my choice, I would rebuild the GT, as the bore may clean up & need only a fresh (TS 250) piston, but you have enlisted a third party, so are perhaps reliant upon their say-so. I'm not making any judgement, but sometimes it helps if you can gain a greater understanding by doing things yourself.

As for the problems that you have endured, I have to wonder @ the perception there is about 'running in' as I have seen many instances of people getting it wrong. Lambretta fan cooled engines are nothing like a car with it's water cooled engine & electric fan, which are much more forgiving of the concept of running in meaning 'plodding along' whereas it means sympathetically using the whole of the revrange & plAging tunes on the gearbox

A fresh bore should never be laboured @ low engine speeds. Far better would be to let it rev so that fan speed is high & intake of fuel is greater to aid cooling.

There should never be the temptation to add more oil to the petroil mix. The engine needs to bed in which excess oil will not help achieve, but the greater danger is that more oil weakens the mixture.

Adam_Winstone
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Tue Dec 10, 2019 1:54 pm

Another quick question, which I may already have missed comment on... I don't suppose that you're running an advance/retard ignition are you? I ask as this could also explain why the bike is running hot at running in revs in 4th but cools when you down-change and/or 'give it some (an advance/retard ignition would then retard further and run cooler).

Just a thought.

Adam

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