lambretta 290 rotax

[holty]

hi folks,
bought an old engine case of an auction site last year, i was told it had a rotax barrel fitted, more than that the seller couldnt tell me, he said it was in his loft for quite a few years, and all the other parts, eg barrel and crank got sold by mistake.i think it was an old air cooled version, and i realy want water cooled, heres some pics of the case.
[url][url=https://flic.kr/p/VPi8DY][/url]dc2ed206334ef21c6e8eec685885452a3_zpsrxokm7xg by stephen holt, on Flickr[/url]
[url632f5d97c38bad262f476b73d5ee7e095_zpsqrha924a by stephen holt, on Flickr][/ur
[url][url=https://flic.kr/p/V8anL5][/url]8ff6f18d4604d05a50f65d5f00cb43ad1_zpsftur22vo by stephen holt, on Flickr[/url]

[holty]

so after a lot of searching i found a suitable barrel, its a rotax 587 barrel, nos off a jetski im only using one cylinder hence 290cc it uses a massive 76mm piston and has a 64mm stroke heres some pics
[url][url=https://flic.kr/p/Vb1JAR][/url]rotax 580_zpsxssx9ipv by stephen holt, on Flickr[/url]
[url][url=https://flic.kr/p/WcYZtP][/url]IMG_1713_zpsp3ckpuma by stephen holt, on Flickr[/url]

[bike grim]

Looks another great project. My Harry Barlow Pro Porting 283cc uses a 76mm jet ski piston with a 62 stroke crank. He is now doing 290cc.

[holty]

Looks another great project. My Harry Barlow Pro Porting 283cc uses a 76mm jet ski piston with a 62 stroke crank. He is now doing 290cc.

oh that sounds good, is it already in use, and have you any pics ?
holty

[bike grim]

Yep used it all last year. Covered a lot of miles including the euro. Only got pics of the exterior I'm afraid. I'll dig some out.

[holty]

that would be great, cheers

[holty]

first job was to make my exhaust flange
[url][url=https://flic.kr/p/WcYZPt][/url]IMG_1719_zpsurdjnfpq by stephen holt, on Flickr[/url]

[holty]

next job was to weld on a pipe for the exhaust, and to weld on a water feed pipe, this distorted it a bit so i turned it down in my lathe to get it nice and flat
[url][url=https://flic.kr/p/Wm2ZZE][/url]IMG_1728_zps6bge9x73 by stephen holt, on Flickr[/url]

[Knowledge]

This looks like the start of a good thread. Bring it on.

The barrel has no inlet port, so are you fitting reed valve crankcase induction? I did this on a TS1 225 a few years back using a CR500 valve fitted above the bumps top, with the carb on the RHS.

[holty]

This looks like the start of a good thread. Bring it on.

The barrel has no inlet port, so are you fitting reed valve crankcase induction? I did this on a TS1 225 a few years back using a CR500 valve fitted above the bumps top, with the carb on the RHS.

yes your right, crankcase induction, i was thinking of using rb reeds as they are compact, i could do with a scrab rb barrel to cut up and weld on, carb will go on rh side like you said.

[holty]

next thing was the head, the jetski head was no good to me as its in 2 parts an inner dome then an outer waterjacket, so i opted for the rotax 580 snowmobile head. these are a one piece head, but a twin so i need to cut it in half and weld up the gaps, heres some pics.
[url][url=https://flic.kr/p/Vb19gt][/url]IMG_1722_zpsu0s1igd4 by stephen holt, on Flickr[/url]
[url][url=https://flic.kr/p/Vb1aGz][/url]IMG_1725_zps0ssrnlk4 by stephen holt, on Flickr[/url]

[url][url=https://flic.kr/p/Vb19Tk][/url]IMG_1723_zpsddyxrlcs by stephen holt, on Flickr[/url]

[Warkton Tornado No.1]

next thing was the head, the jetski head was no good to me as its in 2 parts an inner dome then an outer waterjacket,

I'm intrigued as to quite why a two piece head would not function, as you are retaining water cooling.

Perhaps it's me missing the obvious, so apologies in advance if that's the case.

[holty]

next thing was the head, the jetski head was no good to me as its in 2 parts an inner dome then an outer waterjacket,

I'm intrigued as to quite why a two piece head would not function, as you are retaining water cooling.

Perhaps it's me missing the obvious, so apologies in advance if that's the case.

the original engine is two cylinder but im only using one so i only need half of the head, the two piece head has an o ring sealing the outer water jacket with the inner dome, once cut in half i would have no way of sealing it, heres a pic of the head in my lathe, just cleaning it up a bit with a milling cutter, theres just 2 holes to hole weld up, will put more pics up when i get it back from my mate who is getting his best welder on the job, cheers andy
[url][url=https://flic.kr/p/VPjpEy][/url]IMG_1733_zps56qf7zgv by stephen holt, on Flickr[/url]

[Warkton Tornado No.1]

Thanks for explaining.

It would be great if a similar set-up could be achieved whilst air-cooled for those that don't want to have a radiator.

I look forward to watching the build progress.

[Psychedelicropcircle]

You like a challenge sir will tune in with interest

[holty]

You like a challenge sir will tune in with interest

how true, i always think standard can be improved, adapted, tinkered with until ive made it faster, or is it just to keep me busy
ive had the casing vapour blasted, then used the base gasket as a template to mark what needs welding up and what needs building up, as you can see all four stud hole were wrong, so ive ground them out, and opened the transfers up a bit bigger
they are quite large, im hoping its going to be a nice torquey engine when finished.
[urlIMG_1791_zpsqmmuzicm by stephen holt, on Flickr][/url]
[urlIMG_1789_zps4errkre2 by stephen holt, on Flickr][/url]
[url][url=https://flic.kr/p/V8bSpf][/url]IMG_1790_zpsoq23xhaq by stephen holt, on Flickr[/url]

[holty]

case is away at the welders, ive cut the reedvalve section out of a scrap rb cylinder, it needs more cutting, just getting an idea where to position it.
[url][url=https://flic.kr/p/V8bVaW][/url]IMG_1812_zpspczwcvy5 by stephen holt, on Flickr[/url]
[url][url=https://flic.kr/p/Wpwyic][/url]IMG_1814_zpszsmcack3 by stephen holt, on Flickr[/url]

[holty]

had a delivery from the states, my new piston. took a pic next to an old t5 piston to show the size.
[url][url=https://flic.kr/p/VPjwJU][/url]IMG_1818_zps0seiwm7t by stephen holt, on Flickr[/url]
[url][url=https://flic.kr/p/Wm36C3][/url]IMG_1816_zpsinxywl2c by stephen holt, on Flickr[/url]
[url][url=https://flic.kr/p/VPjvzu][/url]IMG_1817_zps81anvqzy by stephen holt, on Flickr[/url]
last pic shows the lightweight gudgeon pin.

[kennystag]

Anymore on this one.
Cheers
Stag

[holty]

Anymore on this one.
Cheers
Stag

hi stag,
sorry not realy made much progress other than cutting the inlet so it will fit under the bump stop, but only just, and thats with offset cones, ive had a tip that a series 2 shocker will give more clearance as well, still waiting for my casing to be welded up, i am also having a 64mm custom built crank made , the crank webs have been made a bit wider and nitrided, just waiting for the custom pin and it will be assembled with a 125mm rod, will be using a vespa main bearing on the drive side and a packer on the mag housing to get the wider crank in the center of the case, will post an update as soon as ive more to post.

holty