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lambretta 290 rotax

Posted: Thu Jan 21, 2016 6:24 pm
by holty
hi folks,
i bought an engine casing from a well known auction site last year which had been converted to use a motorcycle style barrel which i was told was rotax. after much searching ive not been able to find the cylinder that fits. i suspect it was an old air cooled version, and i want liquid cooled, any way ive now got the barrel i want to use, a rotax 580 twin, im only using one cylinder hence the title lambretta 290, 76mm piston and 64mm stroke. cylinder i bought is nos jetski version, ive got a head on the way from the states(snowmobile version) and piston to order yet, this conversion has already been done before if you look under rotax 300, built by ryan mason, im going to try and keep it as simple as poss, will stick a few photos up, but its not going to be a quick project by any means, will keep pics coming as i go along.
Imagedc2ed206334ef21c6e8eec685885452a3_zpsrxokm7xg by stephen holt, on Flickr
Image8ff6f18d4604d05a50f65d5f00cb43ad1_zpsftur22vo by stephen holt, on Flickr
Image632f5d97c38bad262f476b73d5ee7e095_zpsqrha924a by stephen holt, on Flickr

and this is the barrel , nos

Imagerotax 580_zpsxssx9ipv by stephen holt, on Flickr
ImageIMG_1713_zpsp3ckpuma by stephen holt, on Flickr

Re: lambretta 290 rotax

Posted: Thu Jan 21, 2016 11:01 pm
by holty
first job is to make an exhuast stub, the water feed port under the exhaust port is going to be the water inlet from the water pump, i like the 4 studs to hold it on, its a big exhaust port, will weld a stub to the plate.
ImageIMG_1719_zpsurdjnfpq by stephen holt, on Flickr
ImageIMG_1720_zpsoaaveysv by stephen holt, on Flickr

Re: lambretta 290 rotax

Posted: Fri Jan 22, 2016 5:17 pm
by T5-190
Love it, keep the pictures coming.

Re: lambretta 290 rotax

Posted: Fri Jan 22, 2016 5:30 pm
by dave411
Where is the inlet port?

Re: lambretta 290 rotax

Posted: Fri Jan 22, 2016 7:24 pm
by holty
dave411 wrote:Where is the inlet port?
the inlet on the rotax is a disc valve crankcase induction, i am going to do reed valve induction into the crankcase, i was hoping to use rb reeds as they are compact and easy to get spares for, i might want a scrap rb barrel to cut up to make the inlet, head has just arrived today, just needs a clean then cutting in half as the snowmoblie its off is a twin, will post pics later.
:D

Re: lambretta 290 rotax

Posted: Fri Jan 22, 2016 7:49 pm
by Spanish Fly
holty wrote:
dave411 wrote:Where is the inlet port?
i am going to do reed valve induction into the crankcase, i was hoping to use rb reeds as they are compact and easy to get spares for
Like this?
viewtopic.php?f=7&t=32368&p=239478&hili ... ed#p239478

Re: lambretta 290 rotax

Posted: Fri Jan 22, 2016 8:34 pm
by GBCS
Ahh Steve, you are at it again :D

Does this mean you will be wanting to book spray booth time again in the summer ?

Re: lambretta 290 rotax

Posted: Fri Jan 22, 2016 8:58 pm
by holty
Spanish Fly wrote:
holty wrote:
dave411 wrote:Where is the inlet port?
i am going to do reed valve induction into the crankcase, i was hoping to use rb reeds as they are compact and easy to get spares for
Like this?
viewtopic.php?f=7&t=32368&p=239478&hili ... ed#p239478[/quote

yes similar idea to that.
:D

Re: lambretta 290 rotax

Posted: Fri Jan 22, 2016 9:04 pm
by holty
GBCS wrote:Ahh Steve, you are at it again :D

Does this mean you will be wanting to book spray booth time again in the summer ?
hi andy,
i dont know if i dare ask you to do another, but if you insist :D

i am going to require a little bit of aluminium welding to the engine case, and the head will need welding when ive cut it in half,
i will pop round with the bits and show you what ive got, its going to be a beast no2.
holty

Re: lambretta 290 rotax

Posted: Fri Jan 22, 2016 11:10 pm
by GBCS
no worries