lambretta 290 rotax

[holty]

its a band of 3mm aluminium cut to shape and welded to the case to make it thicker and stronger, i will then be cutting a groove down the center of the case on the inside, known as trenching, this is to give room for the big end, its a 64mm crank and is going to need some clearance, will post pics when its done.

[Knowledge]

[holty]

done a lot of work yesterday, machined the inside of the case to accept the bigger and wider webs, then cut the trench, and then cut the groove for the circlip that holds the main drive bearing in place.

[Adam_Winstone]

^... just the sort of thing that I would be looking to do, for a wider webbed and longer stroke option, if the newer upgraded casings and cranks had not become available. That said, I'm still waiting for Richard to bring out his suitable casing, crank and top end for a big cc air cooled version.

Nice work Holty, I love the fact that you're addressing the issues and progressing the motor, rather than simply bolting together something 'easy' and hoping that it stays together.

Adam

[holty]

thanks for the kind words adam, ive had a half day and got a bit more done, ive matched the transfers to the case sorted out a couple of threads, and some smoothing out here and there.
[url][url=https://flic.kr/p/VPiAcN][/url]IMG_0631_zpsyom10gfk by stephen holt, on Flickr[/url]
[url][url=https://flic.kr/p/WcYnVp][/url]IMG_0645_zpswwuejkwu by stephen holt, on Flickr[/url]
[url][url=https://flic.kr/p/WcYpi4][/url]IMG_0646_zpsopw0kskq by stephen holt, on Flickr[/url]

[Warkton Tornado No.1]

Interesting bearing retention. I wonder whether four modified (reduced head) M6 socket countersink screws in the original holes (countersunk to suit) would have sufficed to ‘clip’ the bearing in place but I’m only commenting, certainly not in a negative manner.

You might well be setting a trend with this project, especially if air cooled barrels are available.

[holty]

[quote="Warkton Tornado No.1"]Interesting bearing retention. I wonder whether four modified (reduced head) M6 socket countersink screws in the original holes (countersunk to suit) would have sufficed to ‘clip’ the bearing in place but I’m only commenting, certainly not in a negative manner.

good thought, only problem is the oilseal needs somewhere to fit, and thats in the area between the circlip and the front face where the seal retaining plate used to fit.

[Warkton Tornado No.1]

Interesting bearing retention. I wonder whether four modified (reduced head) M6 socket countersink screws in the original holes (countersunk to suit) would have sufficed to ‘clip’ the bearing in place but I’m only commenting, certainly not in a negative manner.

good thought, only problem is the oilseal needs somewhere to fit, and thats in the area between the circlip and the front face where the seal retaining plate used to fit.

My mistake!

I had presumed that you had either adopted the sealed (RS or 2RS) bearings or moved seal position to the chain side as per Guy Topper/MSC 'Cooler'

[holty]

no problem, i will post some pics if the bearing, circlip and seal arrangement as it is a little different from anything i had seen before, but has proven to be reliable in a few well tuned scooters so i am not too concerned, ive just taken the case to my local machine shop to have a bit of milling done on the stator side ot the crancase, it was a bit distorted and needs sorting out.

[holty]

i have started work on a cush drive to fit to a lambretta crownwheel to give the gearbox an easier time, its a mixture of lammy clutch and jap trials bike, i wanted to use the full jap clutch but it was not possible, i will be extending the fingers on the crownwheel just like the old 6 plate clutches and using a packer plate,
here a couple of pics
[url][/url]
[imgIMG_0807_zpspl7lworz by stephen holt, on Flickr]http://
[url][url=https://flic.kr/p/VPiFtQ][/url]IMG_0808_zps41ybo0j3 by stephen holt, on Flickr[/url]

[Warkton Tornado No.1]

Hi Holty

I've picked up your PM but don't know why my response appears to sit in the 'Outbox' but you have my email address in one of the messages so that might be the best way of communicating about the clutch inner.

Cheers

Mark

[holty]

Cheers mark,
I've sent you a pm
Holty

[Knowledge]

I don't know why my response appears to sit in the 'Outbox' but .....

Mark

The pm sits in the outbox until the other party picks it up.

[Warkton Tornado No.1]

I don't know why my response appears to sit in the 'Outbox' but .....

Mark

The pm sits in the outbox until the other party picks it up.

Really? My mistake then!

Thank you for informing me

[holty]

[url][url=https://flic.kr/p/Vc47wL][/url]IMG_0932 by stephen holt, on Flickr[/url]

a pic of drive side bearing

[holty]

[url][url=https://flic.kr/p/Vd6mC1][/url]IMG_0933 by stephen holt, on Flickr[/url]
2 extra studs added to the backplate for more strength

[holty]

driveside oilseal fitted
[url][url=https://flic.kr/p/WqMT3b][/url]IMG_0941 by stephen holt, on Flickr[/url]

[holty]

first fitting of the crankshaft, it only just goes in
[url][url=https://flic.kr/p/WqMTTu][/url]IMG_0942 by stephen holt, on Flickr[/url]

[holty]

mag flange and packers just dry fitted to check clearance, i think i will have to machine the inside of the mag housing to get the stator father in so it will line up with the flywheel pickups.

[url][url=https://flic.kr/p/Vd6op7][/url]IMG_0943 by stephen holt, on Flickr[/url]

[holty]

had a test fit of the piston to make sure it didnt hit the casing at bdc i neednt have worried plenty of spare, piston looks very big

[url][url=https://flic.kr/p/WqMVME][/url]IMG_0944 by stephen holt, on Flickr[/url]