1989 Le Mans 1000 Throttle Cables Help Please

Hi All, New on the website and hoping any other Le Mans 1000 owners can assist me with the easiest way to lighten my throttle action. I have been advised by Gutsibits that I need to swap to flat tops for the 40mm Carbs and get custom cables made up , to lighten the spring but the arrangement I have looks like it won’t be that straightforward as cables do not come out carb top but to a spring loaded bracket on side of carb. Can this be junked? Apologies but not genned up on these as previous Guzzis were a Mk 2 Le mans and an 1100 Sport. Any help and advice from someone who has done similar would be very much appreciated. Thanks , John

The top part of the carb is done away with, the flat tops replace them and go in through the top just like a “normal “ carb. Hence you have to get cables made up (unless anybody knows another cable that fits ?

1 Like

Cheers Gino, not sure where to start in sizing the cables required. Be great if someone’s done this and can give me a heads up.

As Gino mentioned, the advice would be to fit flat tops to the carbs and probably the 90 degree elbow kit. Available here …
As for cables, these would need to be made up to suit.

1 Like

Thanks Don. I assume then that I can scrap the spring loaded attachment on the side of the carbs and the slide return spring will close the slide. Which should make it far lighter.
Has anybody had cables made up before? Never done that and no idea how you correctly work out length/free length etc!!! :grimacing:

I have had cables made for a special project bike. J J Cables or Venhill are a couple of names that come to mind. You will need to measure the required length and diameter of the outer cable to suit, and then the length and diameter of the inner cables. You will also need to list the sizes of the nipples top and bottom.
Check to see if any special adjusters are required to be fitted before the nipples are fitted. Not an easy task, but can be done with a bit of time and patience.

1 Like

Thank you Don. Yes I am pretty ok with what I need to do and what is required, it’s the working out required inner v outer lengths that I’m struggling with and not ideal to order custom cables and find out I’ve made an arse of it. Suppose I could start with trying the original cables and try to work out from there where I need to go. In the meantime I’ve removed the original cables and they don’t look great and probably older than I realise so not as free as they should be so will maybe just replace and lube all cables etc in the short term. Cheers.

1 Like

I have 2 lm3’s one of which is my wife’s,hers has the standard bell tops, mines has the flat tops, cables are a pita for the flat tops, I measured and got venhill to make cables (expensive and still needed to fettle them) I’d try new standard cables and slightly lighter springs but be aware I tried the lighter springs before 30 years ago on my Mk1 and they were not good, the slides often wouldn’t shut down.

1 Like

Good call Gino, going to order all new cables, and clean and lube everything that moves. The existing cables are pretty bad and not moving freely and loads of gunk so think it will be an improvement. If I feel like I need it better I can always then try the flat top conversion. Thanks again to all for taking the time to reply and assist me. Cheers :+1:

1 Like

No problem let us all know how it goes!

1 Like

I removed the external springs on the pumps and used lighter internal springs. That and being very careful with the cable routing made a huge difference. Also much cheaper than replacing with flat tops and custom cables. Here’s a link : Removal of accelerator pumps - Le Mans 1000
Heres another: Lemans 5 aftermarket carbs | GuzziTech Forums

I used the medium weight springs suplied by Eurocarb; Internal slide spring - Medium (#8532)
They’ve been in for seven years and have never caused a problem.


Cheers for that Nick. I was hoping to hear from someone who had removed the external springs to find out if that’s possible. I initially removed them but the slides were hanging and not shutting off but motor wasn’t running. Am I being dense here and missing something? I would have thought the internal springs would have handled that.

be a bit careful If I remember correctly the reason LM 1 and 2 had heavy throttles was to prevent the slides locking under suction. maybe slower pull ?

1 Like

But they all had heavy springs! :grin:

I removed the external springs on the pumps and used lighter internal springs. That and being very careful with the cable routing made a huge difference.

I think I did this also. I believe they were the light springs (from Motomecca). But also new cables and routing for minimum bends and minimum friction, are also vital. Never had problems with hanging up. The light springs made all the difference between having to endure agony on a long trip, and ‘doable’.

1 Like

Yeah, thanks Mike. I have ordered new cables and they will be well lubed and routed carefully to make them as good as I can but not a great design IMHO with the extra springs, splitter etc. Two straight cables from carbs to the throttle grip is the way to go but not comfortable with having cables made up correctly. Hey ho.

Ah, my LM1 had a twin-pull Tommaselli twistgrip, might have been a prevous owner modification of course. The splitter shouldn’t be a problem, unless something is wrong with it.

1 Like

No splitter isn’t a problem Mike, just an unnecessary extra piece that doesn’t need to be there. Poorly thought out imho.

Depends what kind of twistgrip you have.

Ditto (I have to type 20 letters!)

Yeah I get that but I’m talking about issues with the standard set up. If I had the twin pull set up I would have scrapped the 3 cables, hi tops, splitter etc but I then need cables made up. Not going there right now. Anyway thanks all for input. Cheers.