LCGB Forums

The ability to post messages is restricted to LCGB members. Any questions contact us at lcgbadmin@googlemail.com

GP150 lockdown project

LAMBRETTA ONLY PLEASE
Show your Lambretta off to us all with pictures of your pride and joy.

GP150 lockdown project

Postby Storkfoot » Wed Aug 26, 2020 5:45 pm

I have a couple of projects on the go, a Vega and an SX150. I had also acquired a few reasonably priced GP150 parts and already had an engine to go in it.

So, I had a lockdown project but, first of all, I face a couple of challenges related to the leggies and forks.

Image

Image
User avatar
Storkfoot
 
Posts: 1279
Joined: Fri May 30, 2014 8:59 pm
Location: Merseyside

Re: GP150 lockdown project

Postby Toddy » Thu Aug 27, 2020 6:09 am

That will keep you busy Paul ;)
User avatar
Toddy
 
Posts: 7202
Joined: Tue May 13, 2014 9:58 pm
Location: East Yorkshire

Re: GP150 lockdown project

Postby dickie » Thu Aug 27, 2020 6:12 am

At the risk of looking stupid, what's wrong with the forks?
dickie
 
Posts: 1287
Joined: Thu Oct 02, 2014 12:32 pm
Location: Tyne and Wear

Re: GP150 lockdown project

Postby Storkfoot » Thu Aug 27, 2020 8:21 am

dickie wrote:At the risk of looking stupid, what's wrong with the forks?

The witness marks on the stem are indicative of them being bent. Placing a set square against them quickly confirmed that.

They have been straightened now.
User avatar
Storkfoot
 
Posts: 1279
Joined: Fri May 30, 2014 8:59 pm
Location: Merseyside

Re: GP150 lockdown project

Postby Storkfoot » Thu Aug 27, 2020 8:27 am

Toddy wrote:That will keep you busy Paul ;)


Thankfully, the frame is in better condition than the legshields (they came from separate scooters). Also thankfully, I know a good fabricator and welder (Just as well, you think :D ) but he is dead busy with other work at the moment.
User avatar
Storkfoot
 
Posts: 1279
Joined: Fri May 30, 2014 8:59 pm
Location: Merseyside

Re: GP150 lockdown project

Postby jonw » Fri Aug 28, 2020 7:51 am

Storkfoot wrote:
dickie wrote:At the risk of looking stupid, what's wrong with the forks?

The witness marks on the stem are indicative of them being bent. Placing a set square against them quickly confirmed that.

They have been straightened now.


I've often wondered how safe this is?
The forks have been bent one way and then bent back, hasn't their integrity been compromised and weakened?
User avatar
jonw
 
Posts: 113
Joined: Mon Jun 02, 2014 8:14 am

Re: GP150 lockdown project

Postby Storkfoot » Fri Aug 28, 2020 8:28 am

I see where you are coming from, same principle as bending a fork to and fro. Hopefully, it’d have to be bent a long way and multiple times before it got into the realms of fracturing. But, I am no expert.
User avatar
Storkfoot
 
Posts: 1279
Joined: Fri May 30, 2014 8:59 pm
Location: Merseyside

Re: GP150 lockdown project

Postby dickie » Fri Aug 28, 2020 10:11 am

Storkfoot wrote:I see where you are coming from, same principle as bending a fork to and fro. Hopefully, it’d have to be bent a long way and multiple times before it got into the realms of fracturing. But, I am no expert.


You're right. It isn't a big deal. Especially if heat is used in the straightening process. That said, you'd be hard pushed to straighten them without heat.
dickie
 
Posts: 1287
Joined: Thu Oct 02, 2014 12:32 pm
Location: Tyne and Wear

Re: GP150 lockdown project

Postby Warkton Tornado No.1 » Sun Aug 30, 2020 11:50 am

Steel is a very good durable material & the forks are flexing all the time throughout their life. They won't work harden & crack in even extreme use.

They are normally straightened via the use of an hydraulic press, though a fly press can be used. With respect, heat is not required via the process that I am aware of. But that could just be 'me!' :D

Yet to use heat with engine mounts, either, & I've done a few! It's all about overcoming friction & if you use deep groove ball bearings in a number of sizes (preferably thrust or taper bearings, but I don't have any!) they go in & out a treat....Oooer! I have oxy-acetylene but avoid heat getting near rubber mounts like the plague. Or Covid 19....
Warkton Tornado No.1
 
Posts: 1675
Joined: Sun Jan 11, 2015 1:27 pm

Re: GP150 lockdown project

Postby coaster » Mon Aug 31, 2020 2:40 pm

I worked for a while in a large motorcycle dealership when I left school and straightening fork legs was a regular job for one of the mechanics as he was a big lad. He used a scaffold pole and bench vice to do the straigtening and a surface plate, V blocks and a dial gague , no heat.......that said, Lambretta forks went straight in the scrap bin as did frames and even slightly damaged panel work :shock:
User avatar
coaster
 
Posts: 2289
Joined: Fri May 30, 2014 1:00 pm
Location: Norfolk, Flying 8 Balls

Re: GP150 lockdown project

Postby dickie » Tue Sep 01, 2020 8:54 am

Gents, you're correct. For the small amount of bending needed there, heat isn't required.

Unless it's been bent a long way or a short amount, many times bending cold is fine.

I should add that although I work in heavy engineering, I'm a control and electrical engineer so I'm around this kind of thing but it isn't actually my area of expertise. So I can't really comment with complete authority.
dickie
 
Posts: 1287
Joined: Thu Oct 02, 2014 12:32 pm
Location: Tyne and Wear

Re: GP150 lockdown project

Postby Warkton Tornado No.1 » Tue Sep 01, 2020 1:30 pm

dickie wrote:Gents, you're correct. For the small amount of bending needed there, heat isn't required.

Unless it's been bent a long way or a short amount, many times bending cold is fine.

I should add that although I work in heavy engineering, I'm a control and electrical engineer so I'm around this kind of thing but it isn't actually my area of expertise. So I can't really comment with complete authority.


As an engineer, although I am mechanically biased & in general a designer, no doubt our outlooks are very similar. I don't think we ever stop learning in our thirst for knowledge, whilst trying not to forget first principles :D

Not wishing to get too far off topic, mechanical advantage, & how best to achieve it, is probably the main essence of our continued passion for Lambrettas & our enthusiasm for this Forum.

The example of extracting engine mounts, & the massive improvement in method by utilising bearings in the process to overcome thread friction needs to be tried to be believed. I must acknowledge Dave Webster (RIP) for advising me of that.

Similarly, the clutch mechanism has been shown to be improved by modification to rack & pinion. No doubt the Chiselspeed conversion is great & VFM, but my finances won't currently allow indulgence. However, I do have a motorcycle mechanism that I aim to adapt ;)

(I reiterate & apologise to Storkfoot & anybody else if I have hijacked this Post :oops: )
Warkton Tornado No.1
 
Posts: 1675
Joined: Sun Jan 11, 2015 1:27 pm

Re: GP150 lockdown project

Postby Storkfoot » Tue Sep 01, 2020 2:55 pm

No problem at all. I put threads up on this forum for discussion and to try to keep it alive, given that it appears significantly quieter than it used to be.
User avatar
Storkfoot
 
Posts: 1279
Joined: Fri May 30, 2014 8:59 pm
Location: Merseyside

Re: GP150 lockdown project

Postby Storkfoot » Thu Oct 01, 2020 4:47 pm

A productive day straightening up a few dings, crossmembers and stabilising the rust inside the frame.
Image
Image
Image
Image
Image
User avatar
Storkfoot
 
Posts: 1279
Joined: Fri May 30, 2014 8:59 pm
Location: Merseyside

Re: GP150 lockdown project

Postby Jeff t » Fri Oct 02, 2020 7:57 pm

Just started a refurb on an Li special what did you use to stabilise the frame?
Jeff t
 
Posts: 69
Joined: Sat Jun 07, 2014 12:00 pm

Re: GP150 lockdown project

Postby Storkfoot » Fri Oct 02, 2020 11:40 pm

Jeff t wrote:Just started a refurb on an Li special what did you use to stabilise the frame?


Diluted Rust Remover from Machine Mart. I just blocked the two drain holes under the frame, pumped it in and left it overnight. Ideally, you should pump in Waxoyl after blasting and painting, I suppose, but what I have done so far will not do any harm.

Heat and a ball pein hammer, followed by a little bit of welding to sort out the tears:

Image
User avatar
Storkfoot
 
Posts: 1279
Joined: Fri May 30, 2014 8:59 pm
Location: Merseyside

Re: GP150 lockdown project

Postby Storkfoot » Fri Oct 09, 2020 2:02 pm

Welding back so dry build next

Image
User avatar
Storkfoot
 
Posts: 1279
Joined: Fri May 30, 2014 8:59 pm
Location: Merseyside

Re: GP150 lockdown project

Postby gaz_powell » Fri Oct 09, 2020 7:34 pm

Another nice project on the go, Paul.
gaz_powell
 
Posts: 1953
Joined: Sat May 31, 2014 7:56 pm
Location: Hartlepool

Re: GP150 lockdown project

Postby Storkfoot » Fri Oct 09, 2020 9:40 pm

gaz_powell wrote:Another nice project on the go, Paul.


Gaz, My mate who saved the legshields with his welding abilities never wants to see Lambretta legshields again. I tried to reassure him that he had saved a bit of history. He wasn’t convinced :shock:
User avatar
Storkfoot
 
Posts: 1279
Joined: Fri May 30, 2014 8:59 pm
Location: Merseyside

Re: GP150 lockdown project

Postby bike grim » Sat Oct 10, 2020 1:44 pm

Looks a good job. I’ve just bought a new welder and want to have a go at some legshields so if anyone has an old set they want to donate to practice on let me know (and panels)
User avatar
bike grim
 
Posts: 689
Joined: Tue Jun 03, 2014 2:51 pm

Next

Return to Show Your Ride

Who is online

Users browsing this forum: No registered users and 1 guest