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TDR big bore kits


matt1

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I currently have a new welded stoke stroke crank with a set of 66.5 cylinders that will need to be resleeved next time I rebuild. I was looking on the TDR website and found a set of 68-70 mil sleeves that come ported for a decent price. Has anyone every used them and if so how much machine work must be done to install them. I have a machinist that owes me a favor so I was think about doing this instead of getting new cylinders. They also have a sleeve that starts at 70 and can be bored to 72. If anyone has every used these I would like to here some input on how they ran. Looking to use a stock head, stock carbs bored, and FMF fatty pipes in my YFZ chassis. How many cc s would a 70 mil bore on stoke stroke be?

 

http://www.bansheedepot.com/products.asp?cat=45

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My thought was either do this or a stock stroke serval. Don't really want to spend the money on a new crank and I am sceptical about buying used ported cylinders because I do not have the ability to tell the visual difference between a good port job and a not so good port job. By the time you buy another set of stock jugs and have them ported I would not think that there would be much savings over buying a serval. I was considering these sleeves because they are ported and cheap, 170 for new ported sleeves seems like a good deal if the porting is good and makes decent power.

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The porting of them sleeves is probably a port job, tailored for top end. It won't be customized to your exact riding conditions and mods, like a site sponsor port job is. Not to mention it costs like $200 per cylinder for sleeve install and then you still gotta do port work to the cylinder casting after the sleeves are in, to blend in any mis-match of ports etc. It will cost more in the end to have big bore sleeves installed than to get the stock cylinders ported.

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Steer clear of the big bore sleeve kits for stock cylinders! They are just old tech, and next to impossible to keep sealed up after 68mm so they aren't sucking water. Then there is the issue of not having dome material, so stress usually wins once the domes are opened up as well. I worked with Dave noss on trying to find a happy medium, but it was just a no go.

 

It can be done, but to do it properly with an o-ringed one piece head with custom chambers, re enforced head gasket, low compression to keep the sleeves from pushing down, etc. Even then you still gotta get some porting so the cost just keeps going. And it is still an unpredictable motor.

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