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Thanks for posting that! They've chosen a good machine for this, I got my 350 Desmo up to 110 mph once.... And that was before I had it rebuilt and the big carb added.

I hope Christi is tiny.

Stephanie
 

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A 350 springer race bike that I was formerly associated with was good for a tick over 140mph. We used the springer head since they did not have a desmo head in the product line at that time. Hard to say if it would have added any more agressive cams or added reliability.

b.

dresda said:
Thanks for posting that! They've chosen a good machine for this, I got my 350 Desmo up to 110 mph once.... And that was before I had it rebuilt and the big carb added.

I hope Christi is tiny.

Stephanie
 

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I should have mentioned that I was on a public road!

Stephanie
 

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it may end up being the fastest ducati single, but I think the rules will prevent a modern head on an older motor to race in a production class. no matter what class one runs in, bonneville is a blast. it is worth going to watch just to see the amazing machines no matter how many wheels they have. every thing from an bone stock Crosley to diesel trucks going way over 200 along with many cars and bikes of all types. fun to wander the pits to get a close look at all the different solutions that folks have come up with to make thier vehicle fast. just wear LOTS of sunscreen!
 

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Not sure what you mean about "modern head" ? Can you clarify ?

jbcaddy said:
it may end up being the fastest ducati single, but I think the rules will prevent a modern head on an older motor to race in a production class. no matter what class one runs in, bonneville is a blast. it is worth going to watch just to see the amazing machines no matter how many wheels they have. every thing from an bone stock Crosley to diesel trucks going way over 200 along with many cars and bikes of all types. fun to wander the pits to get a close look at all the different solutions that folks have come up with to make thier vehicle fast. just wear LOTS of sunscreen!
 

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Discussion Starter #7
bevel450 said:
Not sure what you mean about "modern head" ? Can you clarify ?
From the web site.

"After some research I have decided to use a 450 bottom end so I am in a quest for a 450 motor. The frame has been secured but not obtained. Its from an AHRMA racer.

The current plan is to "graft" a 748 head onto a 450 head. A super short stroke 249cc will emerge for this odd combo but, it will deliver the winning hp and rpm we need.

The reason for the 450 bottom end is because it will fit the piston we will use for the 748 head. The great news here is that we have the room to install big flywheels to reduce unwanted pulses, making it easier for Christy to accelerate. The limitation is that the OD of the valve perimeter being 84mm. With repositioning ($$$$$$$$) we can get it to 80mm but I am not counting on that although there is room for it. Its going to be plenty of machining work in any event!"



Sounds like a lot of machine work to me.

G
 

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This sounds pretty creative to me, but the devil is always in the details. Unfortunately Ducati, when they initially raised the displacement of the 250 to 350, failed to improve the lower end and expand the distance from the crank to the tranny, thus limiting flywheel diameter.

The 450 vibrates like....well, you have no idea how much they vibrate. Of all that they discuss here, that makes the most sense in moving toward a real race engine.

As to your comment that it sounds like a great deal of machine work....you have no idea. THE method for making a Duc single really go, is to totally re-angle the intake valve. Even if you do it often it is a solid 100 hr. job.

( Duc singles have some of the worst port design I have ever seen. Awful.)





gusanito said:
From the web site.

"After some research I have decided to use a 450 bottom end so I am in a quest for a 450 motor. The frame has been secured but not obtained. Its from an AHRMA racer.

The current plan is to "graft" a 748 head onto a 450 head. A super short stroke 249cc will emerge for this odd combo but, it will deliver the winning hp and rpm we need.

The reason for the 450 bottom end is because it will fit the piston we will use for the 748 head. The great news here is that we have the room to install big flywheels to reduce unwanted pulses, making it easier for Christy to accelerate. The limitation is that the OD of the valve perimeter being 84mm. With repositioning ($$$$$$$$) we can get it to 80mm but I am not counting on that although there is room for it. Its going to be plenty of machining work in any event!"



Sounds like a lot of machine work to me.

G
 
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