7mm

[Leadfoot350]

for the trenching part on a 7mm just lay the crank in there and see where its going to hit then start grinding. Its about 2mm to take out if that. For a 10mm you might be close on some parts of going through but I have never done a ten. The 7 is really easy. What cylinders are you going to put on this engine. 7mm is the biggest you can go for stock cylinders and cuting the domes will be hard. You will have to have blank ones and it would be best if you had a head that took the universal pro-design domes because they are a lot cheaper then if you have the trinity ones like me. They were 90 for blanks and then another 90 to be cut and then they messed them up so another 90 and then another 90 to get cut again. You are going to have to put a thicker spacer under the stock cylinders and you can buy them at white knuckle racing for 10 bucks each. I went with the .42 spacer but with my pistons comming out of the tops so much I would have liked to try out a thicker one. With the .42 base gasket the intake transfers are 131.5 which is pretty good and if you go with a thicker one I believe they would be higher but its been a while. Which this engine its limiting you to pretty much a really hot duner/ hill shooter but its still a blast to dune with. If you need help setting this up then give Kevin a call. He lives in Encinitas and set mine up for me. Great guy and is always helpfull and excited about your projects. Herrjuggsracing.com is his web site. It you are going with cubs then it would be a whole lot easier and give you off the shelf products to buy but would cost a lot more and you could go with 10mm cubs easy.

[FireHead]

7mm is the biggest you can go for stock cylinders and cuting the domes will be hard. You will have to have blank ones and it would be best if you had a head that took the universal pro-design domes because they are a lot cheaper then if you have the trinity ones like me. You are going to have to put a thicker spacer under the stock cylinders and you can buy them at white knuckle racing for 10 bucks each.

 

None of that quote is true. (except for maybe the cost of the spacer plate) :thumbsup:

[Bansh-eman]

None of that quote is true. (except for maybe the cost of the spacer plate) :thumbsup:

the part about the domes is lol being more expensive that is

Edited March 20, 2007 by Bansh-eman

[FireHead]

the part about the domes is lol being more expensive that is

 

The +7mm max stroke on the crank with stock jugs is bs as well. :geek:

[blowit]

The +7mm max stroke on the crank with stock jugs is bs as well. :geek:

 

 

Your limiting factor really becomes porting timing with the OEM jugs. Long stroke engines require different port locations to make max HP.

 

 

 

B

[FireHead]

Your limiting factor really becomes porting timing with the OEM jugs. Long stroke engines require different port locations to make max HP.

B

 

I agree. If you are willing to resleeve the stock cylinders the limit winds up being something like +16mm stroke (I can't remember what it is exactly. I figure it out once). I think the largest you can go with a commercially available sleeve is +14mm. This would be a question to ask on Planet Sand. I am not old enough to know what was done to Banshee engines before the appearance of aftermarket cylinders in the industry. :thumbsup:

[Leadfoot350]

oh sorry im wrong you can go bigger but you will have to resleave the stock cylinders which is not cost effective. I was talking about making the most hp for the $. Looks like a lot of guys have opinions here......

[FireHead]

oh sorry im wrong you can go bigger but you will have to resleave the stock cylinders which is not cost effective. I was talking about making the most hp for the $. Looks like a lot of guys have opinions here......

 

If you can resleeve the cylinders yourself, then it might still make economic sense. If not, then you are correct in saying that there are better options out there.

[blowit]

If you can resleeve the cylinders yourself, then it might still make economic sense. If not, then you are correct in saying that there are better options out there.

 

 

 

 

 

Now I feel old. The big trend in stroker banshees hit in the mix 90s from Trinity. The biggest stroke for a while was an 8mm. Then 10-12mm was tested with other big bore sleeves. I know they bad a bunch of setups but none of them were ever real hitters. The stock banshee cylinders, as is, are restricted to a 6mm over stroke to keep porting within max HP timings. The hindering factor becomes the transfer port timings that, if allowed to become excessive, with not allow proper blow down and reverse port flow occurs. You cannot pop a piston out of the hole more than 3mm so you would have to raise the deck which would also raise port timing.

 

Many motors were made in the day that were NOT within the max HP window but still made some power just because of displacement. If you were to get sleeves to allow for more stroking, you must add material to the cylinder ports to allow for proper port matching. When big bore sleeves are used with the stroking, this reduces port volume thus flowing less when the engine really needs more. Not good for the GO factor. All in all, a waste of time IMO. The cheetahs with PVs are the way to go. MUCH better port layout, more volume, just better.

[FireHead]

Now I feel old. The big trend in stroker banshees hit in the mix 90s from Trinity. The biggest stroke for a while was an 8mm. Then 10-12mm was tested with other big bore sleeves. I know they bad a bunch of setups but none of them were ever real hitters. The stock banshee cylinders, as is, are restricted to a 6mm over stroke to keep porting within max HP timings. The hindering factor becomes the transfer port timings that, if allowed to become excessive, with not allow proper blow down and reverse port flow occurs. You cannot pop a piston out of the hole more than 3mm so you would have to raise the deck which would also raise port timing.

 

Many motors were made in the day that were NOT within the max HP window but still made some power just because of displacement. If you were to get sleeves to allow for more stroking, you must add material to the cylinder ports to allow for proper port matching. When big bore sleeves are used with the stroking, this reduces port volume thus flowing less when the engine really needs more. Not good for the GO factor. All in all, a waste of time IMO. The cheetahs with PVs are the way to go. MUCH better port layout, more volume, just better.

 

You most certainly can put a piston more than 3mm out of the bore. I think I am about 5mm out of the bore on my red bike. Depending on the port design of the aftermarket sleeve, you may or may not have to add material to the stock cylinder areas to achieve a workable transfer tunnel and proper port matching. I did not add any material to the cyclinders or the case on my red bike.

 

While I will agree that what I have done was not the best use of my time if it were measured against horsepower made, but I certainly had fun doing it. It is very ignorant to state the stroke and port limitations the way you did on the basis of there being better options out there. If you were to aks me if I would do what I have done with some of my engines over again, I would have to think about it for awhile before I would say no. If I hadn't done that stuff previously, I would never have had enough experience to build my triple now. :geek:

[blowit]

You most certainly can put a piston more than 3mm out of the bore. I think I am about 5mm out of the bore on my red bike. Depending on the port design of the aftermarket sleeve, you may or may not have to add material to the stock cylinder areas to achieve a workable transfer tunnel and proper port matching. I did not add any material to the cyclinders or the case on my red bike.

 

While I will agree that what I have done was not the best use of my time if it were measured against horsepower made, but I certainly had fun doing it. It is very ignorant to state the stroke and port limitations the way you did on the basis of there being better options out there. If you were to aks me if I would do what I have done with some of my engines over again, I would have to think about it for awhile before I would say no. If I hadn't done that stuff previously, I would never have had enough experience to build my triple now. :geek:

 

I happen to have a piston on my desk that meaures 3.4mm from timing edge to top of first ring land. 5mm does not work. We have built about 30 of those bikes. Sorry to sound ignorant but we have just done so many of those and know the dims of banshee engine well. Not saying you can;t go bigger, you are just not getting the most it could offer because port timing will ultimately suffer. We try to be honest on this stuff because we want the best bang for the buck too. I am not sure what piston you are using but the piston we commonly use and the banshee wisecos are limited. We have removed the top ring to allow for the extra travels but low end compression suffers. Not sure of your setup but we wrote engine analysis software to help ourselves with these questions.

 

We have seen many BLACK crank cases from flow reversal.

 

There just is nothing that the OEM cylinder has going for it compared to the Cheetah other than cost. This is just my opinion though. I still have bikes with the OEM cylinders too.

[FireHead]

I happen to have a piston on my desk that meaures 3.4mm from timing edge to top of first ring land. 5mm does not work. We have built about 30 of those bikes. Sorry to sound ignorant but we have just done so many of those and know the dims of banshee engine well. Not saying you can;t go bigger, you are just not getting the most it could offer because port timing will ultimately suffer. We try to be honest on this stuff because we want the best bang for the buck too. I am not sure what piston you are using but the piston we commonly use and the banshee wisecos are limited. We have removed the top ring to allow for the extra travels but low end compression suffers. Not sure of your setup but we wrote engine analysis software to help ourselves with these questions.

 

We have seen many BLACK crank cases from flow reversal.

 

There just is nothing that the OEM cylinder has going for it compared to the Cheetah other than cost. This is just my opinion though. I still have bikes with the OEM cylinders too.

 

Are you using stock Banshee pistons.............? I think I should have specified what pistons I was using. I think the you maybe right about the Wiseco Banshee pistosns. The Blaster pistons and YZ pistons are a certainly different. I think I may have made the pistons that are in my red bike the more I think about it. I supposed it will be like opening a Christmas present when that engine fianlly lets go.

 

I am a bit curious as to what the software you wrote does? Is it just an fancy excel sheet or are you actually doing some rudementary simulation?

 

I personally feel that even the newest Cheetah DM cylinders leave a bit to be desired. If I were buying cylinders I think I would be looking to get ahold of something from Twister. Instead, for some reason, I think it will be fun to make my own cylinder block for my triple.

[blowit]

Are you using stock Banshee pistons.............? I think I should have specified what pistons I was using. I think the you maybe right about the Wiseco Banshee pistosns. The Blaster pistons and YZ pistons are a certainly different. I think I may have made the pistons that are in my red bike the more I think about it. I supposed it will be like opening a Christmas present when that engine fianlly lets go.

 

I am a bit curious as to what the software you wrote does? Is it just an fancy excel sheet or are you actually doing some rudementary simulation?

 

I personally feel that even the newest Cheetah DM cylinders leave a bit to be desired. If I were buying cylinders I think I would be looking to get ahold of something from Twister. Instead, for some reason, I think it will be fun to make my own cylinder block for my triple.

 

 

I would agree that a custom block would be pretty tight but we just would not have the time to invest in the 5 axis programming for a billet piece and I doubt anyone would buy a 8-10k$ block. Would be nice as a show piece though.

 

Software, we only made what we needed but yes it is "limited" simulation software. We link our data from the dyno and flowbench to obtain VERY specific data that we need. We did not see any need for the fancy bells and whistles seen in commercial software. I would say that our 3D port flow analysis is extremely helpful for our needs. We just kinda build as we go along.

[FireHead]

I would agree that a custom block would be pretty tight but we just would not have the time to invest in the 5 axis programming for a billet piece and I doubt anyone would buy a 8-10k$ block. Would be nice as a show piece though.

 

Software, we only made what we needed but yes it is "limited" simulation software. We link our data from the dyno and flowbench to obtain VERY specific data that we need. We did not see any need for the fancy bells and whistles seen in commercial software. I would say that our 3D port flow analysis is extremely helpful for our needs. We just kinda build as we go along.

 

You don't necessarily need a 5-axis machine to get the job done. If you are willing to do a few more clampings you can get just as nice of product in the end. I have no idea what retail would need to be for what I am working on? I wouldn't be doing this project if the owner of American Metal Supply didn't have a local sprint car racing fetish (I slip him tickets every once in awhile). Each billet for a case half is about $500 retail and If I had to guess the billet for the cynider block is about $1000 retail. Plus, all the other blocks of aluminum and steel for the other parts and fixtures add up real quick. The bar that I am making alot of my crankshaft out of it would cost a normal person about $6000 and you would have to wait one or two years to get it (god damn Aubert & Duval).

 

Is this software something you created in house or is it a MathCad based sort of thing?

[Leadfoot350]

firehead I used a blaster piston in mine and there is no way 5mm is going to come out of that cylinder. I didnt even like the idea of 3.5mm coming out so that is why we used a thick base gasket. Also there are no heads on the market that you can plung cut a 5mm hole into first and then design your dome after. Blowit im with you on the limitaions of the stock cylinders. I think if I was going to do it again I would get a 10mm crank and come cubs or cheetas. That is the best bang for the buck IMO. That way you could run off the shelf parts and if you wanted to you could run domes big enough for pump gas if there was too much power. Oh well, next time when this thing is old and tired.