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General Category => General Discussion => Topic started by: Simon_London on May 18, 2018, 03:25:39 PM

Title: Is it worth increasing a Le Mans MK 1/2 engine from 850 to 950?
Post by: Simon_London on May 18, 2018, 03:25:39 PM
 Is it worth increasing a Le Mans MK 1/2 engine from 850 to 950?

Any thoughts?

Bike has 36mm carbs, fast road cam, lightened flywheel + Lafranconi comps.

Just wondering if anyone has direct experience of doing this and how it changes the pick up, feel and power of the engine?

Thanks

Title: Re: Is it worth increasing a Le Mans MK 1/2 engine from 850 to 950?
Post by: guzzista on May 18, 2018, 04:14:43 PM
Not really.  In my case all the above specs as in your bike. Got the 950 Gilardoni  with modded  spigot as it was the only thing available at the time. A bit more grunt at the bottom, noticeable, but not earth shattering. Engine seemed to rev easier with the the 83mm bore. Thinking that head ports  with flow bench work  and 40mm carbs may help. YMMV
Title: Re: Is it worth increasing a Le Mans MK 1/2 engine from 850 to 950?
Post by: pressureangle on May 18, 2018, 04:37:52 PM
'Guzzi intake ports are...not very good stock. Even a mild porting job by a *competent* porter with a flow bench will probably gain more across the board than the additional displacement trying to suck through the same shakey hole for the money. Plus, done right porting is all gain and zero loss from idle to redline.
Title: Re: Is it worth increasing a Le Mans MK 1/2 engine from 850 to 950?
Post by: rodekyll on May 18, 2018, 05:03:34 PM
Or buy an 1100 and put the cam in that.
Title: Re: Is it worth increasing a Le Mans MK 1/2 engine from 850 to 950?
Post by: Dukedesmo on May 18, 2018, 05:07:03 PM
As per Guzzista's post above, probably not a huge difference. I did mine because I had a piston to valve interface and couldn't find new pistons so bought a Gilardoni 950 kit.

It does have a better low down - mid range pull but not a huge difference, using the 'butt dyno' I'd guess maybe a 5hp increase?

Unless by necessity, I wouldn't bother. 
Title: Re: Is it worth increasing a Le Mans MK 1/2 engine from 850 to 950?
Post by: pressureangle on May 18, 2018, 06:31:09 PM
Or buy an 1100 and put the cam in that.

Economically, probably the best answer.
Title: Re: Is it worth increasing a Le Mans MK 1/2 engine from 850 to 950?
Post by: stubbie on May 18, 2018, 06:51:50 PM
No real difference.
Title: Re: Is it worth increasing a Le Mans MK 1/2 engine from 850 to 950?
Post by: Tom on May 18, 2018, 09:24:37 PM
Shift at 6K rpm's and cruise at 5K.  That's only if you don't do that now.  :thumb:
Title: Re: Is it worth increasing a Le Mans MK 1/2 engine from 850 to 950?
Post by: JJ on May 19, 2018, 06:11:54 PM
Not really.  In my case all the above specs as in your bike. Got the 950 Gilardoni  with modded  spigot as it was the only thing available at the time. A bit more grunt at the bottom, noticeable, but not earth shattering. Engine seemed to rev easier with the the 83mm bore. Thinking that head ports  with flow bench work  and 40mm carbs may help. YMMV

Agree with guzzista 100%.... :thumb: :cool: