czakky Posted March 5, 2017 Share Posted March 5, 2017 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. Link to comment Share on other sites More sharing options...
68C Posted March 5, 2017 Share Posted March 5, 2017 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. Link to comment Share on other sites More sharing options...
pete roper Posted March 7, 2017 Share Posted March 7, 2017 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. Link to comment Share on other sites More sharing options...
czakky Posted March 7, 2017 Author Share Posted March 7, 2017 Ok this makes sense. I didn't know the G5 pistons were flat. Link to comment Share on other sites More sharing options...
pete roper Posted March 7, 2017 Share Posted March 7, 2017 Just do a fill and do the sums, it's not difficult and the figures don't lie. Link to comment Share on other sites More sharing options...
68C Posted March 7, 2017 Share Posted March 7, 2017 Yeah, You are right, I did'nt think about those domed Le Mans pistons. Link to comment Share on other sites More sharing options...
czakky Posted March 7, 2017 Author Share Posted March 7, 2017 You go from Italian stallion to low compression mule, eh? Link to comment Share on other sites More sharing options...
Baldini Posted March 13, 2017 Share Posted March 13, 2017 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. Link to comment Share on other sites More sharing options...
swooshdave Posted March 23, 2017 Share Posted March 23, 2017 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. Link to comment Share on other sites More sharing options...
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