OG Lemans heads

[czakky]

Question for the classic guzzi knowledgeable here. In my semi serious search for a classic zen cruiser cycle I stumbled across a sweet v1000 G5. Supposedly with lemans mk 1 heads. My questions on this are: First off is a mk 1 head compatible with a v1000? Looks like 85mm bore vs 83? That doesn't add up to my math...

Also if it's possible what are the necessary modifications a guy would have to do to make this work? Besides fuel delivery etc.

Long shot on buying it but I'm always trying to learn.

[68C]

I fitted 950cc barrels to my 850 T3, I used the original T3 heads, I also lightened the flywheel. I used the T3 carbs. Now the T3 heads with larger barrels would have raised the compression ratio a little and the lighter flywheels should have meant a little more acceleration, in truth after the several months it took to swap things around I cannot really say I noticed any real improvement.

 

I reckon the LeMans mk1 heads on the T5 barrels should run perfectly, unless you also fit the larger LeMans carbs probably not much will change.

 

A lot of people think the T5 was the best Guzzi, good spread of power unlike the V11 which seems to have less bottem to mid range (real world) power. They are also bullet proof, the T5 will survive a crash better than the V11.

[pete roper]

The difference between the small valve heads and the mid valve heads is that the combustion chamber is enlarged for the bigger valves. That means that if you use them with the flat topped G5 Pistons you end up with a very low compression ratio so all the benefits of the bigger valves are lost. To make it work properly you need Pistons with a dome. Easiest way to achieve this is just buy a set of 88mm Gilardonis for a roundfin LeMans.

[czakky]

Ok this makes sense. I didn't know the G5 pistons were flat.

[pete roper]

Just do a fill and do the sums, it's not difficult and the figures don't lie.

[68C]

Yeah, You are right, I did'nt think about those domed Le

Mans pistons.

[czakky]

You go from Italian stallion to low compression mule, eh?

[Baldini]

I have a T3 based bike with 950 Spada (flat top) pistons using LM11 heads/36mm carbs & I love it. It's real low compression, but the upside of that is: it's real relaxing to ride. And forgiving. Pulls like a train - well, a small train.

[swooshdave]

Question for the classic guzzi knowledgeable here. In my semi serious search for a classic zen cruiser cycle I stumbled across a sweet v1000 G5. Supposedly with lemans mk 1 heads. My questions on this are: First off is a mk 1 head compatible with a v1000? Looks like 85mm bore vs 83? That doesn't add up to my math...

Also if it's possible what are the necessary modifications a guy would have to do to make this work? Besides fuel delivery etc.

Long shot on buying it but I'm always trying to learn.

 

The LeMans heads should have 6mm studs on the intakes, if I recall correctly. The small valve heads have 8mm.