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Discussion Starter #1
Does anybody know how much it costs to have a motorcycle engine blueprinted?
Should it be done on a brand new engine or can an in-use engine be used?
Any reputable shops in the Northeast who can do this?

thank you in advance.
 

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Far as I know, blueprinting a motor has always meant setting every clearance on the motor to the middle of the range allowed.
When Detroit was building junk and tolerance stack ups made a significant difference in performance, then blueprinting meant something. Modern motorcycle motors are pretty much blueprinted at assembly.
 

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Far as I know, blueprinting a motor has always meant setting every clearance on the motor to the middle of the range allowed.
When Detroit was building junk and tolerance stack ups made a significant difference in performance, then blueprinting meant something. Modern motorcycle motors are pretty much blueprinted at assembly.
Yeah this is my impression as well. Weigh all rods and pistons making them the same. Fit all bearings not in middle spec. Test all valve springs for height, and load power. Making everything uniform.
 

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Discussion Starter #6
No, this was not a joke.
I recently read in a motorcycle magazine about a racing team in Europe using the same bike as mine.
They blueprinted the engine which gave them a 10hp gain in performance.
 

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Either the article is stretching the truth a long ways,
Or Triumph's quality control has gone in the toilet.
Or maybe they're using some other than the accepted definition of "blueprint".

Blueprint means using only factory stock parts, and 10 hp is what, 10% power increase? By replacing stock parts with stock parts?
It's pretty common to modify the 600 class bikes for an extra 10 hp, but the bikes are not at factory settings afterwards. May still fall into the stock category though.
 

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Well maybe..... Making pistons weigh the same, ballancing the crank, same deal with the rods, making sure all valve springs work equally, and that bearings are all matched will increase the engines ability to create rpm.


RPM is usually limited by friction, hot spots, and over all engine ballance. Weak valve springs allow a valve to float at higher rpms. When a valve floats you loose compression, which feels like a skip or engine miss sort of.

In theory blue printing frees an engine to be able to produce all the power it can.

A lot of time is spent examining each part, polishing each bearing surface, installing and then disassembly again to check fit. Babbit bearings are made to fit the crank and rods all the same, with all the same clearances, not too tight and not too loose. A tool to test is called plasti-gauge.

A really good scale is use to weigh each part and drilling holes to lighten parts happens, drilling in non-stressed locations to make each part lighter, and have all similar parts weigh the same.

Many identical looking parts will not be with in 20 grams of the same weight, so you need to weigh them all and lable them all, and then make each one the same.

So in a way this can increase power. This labor is tedious, and expensive since all these things take time to do and finding a cheap machineist isn't likely.

Just matching rods is a chore. First you need to know what each one weighs, then make them all the same as the lightes rod. If a drill bite off a little too much, the choice then it to droll them all to be lighter and weigh them all again, or get a new rod and make it the same as all the rest.

Once done there is still going to be that = / - factor.

If you have ever seen a crank shaft with drilled holes in the counter ballance, these are crude factory ballencing holes, and are common in many cranks right from the factory, but these are not usually perfect by any means. Just to get that riight a considerable amount of work goes into making a jig, that is closer to perfect that the factory can get in a speedy production line sence of just good enough.
 

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No mention of minimum deck height or head gasket thickness to boost compression a bit? That is always good for a few ponies.
 

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No, this was not a joke.
I recently read in a motorcycle magazine about a racing team in Europe using the same bike as mine.
They blueprinted the engine which gave them a 10hp gain in performance.
It would be ten of the most expensive horsepower you ever gained.

You did notice it was about a racing team and clearly one that is running at the edge.

I had a friend who drag raced, even set a national record on his old H2. He never had a crank balanced because he could gain so much more in so many other areas with the money. In other words, when you finally hit the point where you can't gain more power for less money, do the blueprinting. Till then there are a lot of easier ways to gain horsepower.

Of course if you have the money why not.

Everyone is right though, it is machining and building the engine as closely as humanly possible (for the shop doing the job) to the specification with exceedingly tight tolerances. Each combustion chamber is shaped as closely as possible with the same volume as possible to the desired specs. Each port is ported to flow as closely as possible to the others and at the desired spec. And so on. See where the money goes?
 

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Each connecting rod is match weighted, big ends equal, little ends equal within 1/4 gram
then rocker arms within 1 gram ad infinitum. If you're in a racing series that prohibits weight removal, you need to have MANY multiples of each piece. 100 rocker arms to have four within the same weight. REALLY expensive. Read Smokey Yunick's book, it's old but accurate.

Reminds me of my SCCA days.
 
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