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Post by headcoats on Sept 16, 2018 15:56:40 GMT 1
Simple question , how the f##k do you get these in ARGGGHHHHHH !!!!!!
Had a quick try by putting the bung in boiled water , but no way is it going in
What if anything needs to be trimmed to get them in nice and tight and flush
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Post by wallcraft on Sept 16, 2018 17:17:19 GMT 1
Yep i had the same prob, their a right bast*** to get in. Had to put mine gently on the stone wheel on the bench grinder and fettle the barrel with needle files then push fit with silicone nice and flush. Then water test for leaks next day. Don't worry to much if their not completely flush as when the barrel is tightened down they will clamp up!! Hopefully. Will interesting to see what other chaps do?
Mark.
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Post by Trubrit on Sept 16, 2018 17:38:51 GMT 1
I Fill Them In With Epoxy , If Your Not Using Cases With Extended Base Gasket Area At The Front Like Banshee Cases The Rubber Bung Ends Up Hanging Half On Half Off The Cases
Dave
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Post by headcoats on Sept 16, 2018 18:19:59 GMT 1
Using standard YPVS cases so I guess these feckers need securing in good and firm Athena should have machined these at the factory really FFS Do you think 3 bond will seal them in nice ? To me it seems the depth of the outer thinner part of the barrel needs machining
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Post by wallcraft on Sept 16, 2018 18:34:03 GMT 1
Your right about the maching depth, had to get the Dremel on mine. Yet to run mine but hopeful it won't leak!! Dave what epoxy do you use and how do you stop it falling through when filling? Thanks.
Mark.
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Post by headcoats on Sept 17, 2018 9:33:59 GMT 1
I really think it needs a machine shop to cut the correct shape into the barrels for the bung but wouldn't be happy about that !
There must be dozens of these conversions already done , so please chip in as it's all useful information :-)
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Post by Trubrit on Sept 17, 2018 9:39:52 GMT 1
If You Buy Them Thu Roger He Does Machine So The Bungs Fit Well , I Thin The Bung Down & Fill With JB Weld Or Something Like .
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Post by bare on Sept 17, 2018 17:23:30 GMT 1
Using standard YPVS cases so I guess these feckers need securing in good and firm Athena should have machined these at the factory really FFS Do you think 3 bond will seal them in nice ? To me it seems the depth of the outer thinner part of the barrel needs machining Small injection of Reality : Banshees are THE intended market /fitment... period. Valvie engines are a very small /incidental market and only because the Cyls just happen to fit the earlier cases .. mostly.
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Post by headcoats on Sept 17, 2018 21:05:40 GMT 1
Yep i had the same prob, their a right bast*** to get in. Had to put mine gently on the stone wheel on the bench grinder and fettle the barrel with needle files then push fit with silicone nice and flush. Then water test for leaks next day. Don't worry to much if their not completely flush as when the barrel is tightened down they will clamp up!! Hopefully. Will interesting to see what other chaps do? Mark.
Mark when you say ,they are not completely flush, how much are you talking ?
I have rubbed them down so they will fit in the barrels , but are about 2mm higher than the gasket face !
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Post by wallcraft on Sept 17, 2018 22:34:13 GMT 1
I managed to get mine pretty much flush just slightly raised about .25 - .5mm and siliconed in, left overnight one barrel at time with the bottom barrel spigot placed in between open vice jaws not tightened up, with heavy weights on top of the head studs. Next day removed weights, put the barrel drain plug in and then filled the barrel water jacket to check for leaks around the bung. Great, water tight. This method combined with the clamping pressure when finally assembled should be enough. May sound a bit iffy but confident all will be fine. Dave's method above sounds like a good way to. Bare is also right about the banshee casings having a fatter front edge were the bung sits on the mating case. Unfortunately we've not blessed with an abundance of banshee casing this side of the pond. Pretty sure the Ypvs 250 strangely has the fatter front edge casings!!
Mark
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Post by headcoats on Sept 18, 2018 8:07:26 GMT 1
So I guess my next question is how flush do they need to be to compress fully when the base gasket and the 4 bolts are tightened up ?
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Post by wallcraft on Sept 18, 2018 8:31:39 GMT 1
There's no rule to this but I would say before tightening down no more than .75mm. 1mm might be compromising., so when fully torqued up they will be flush. The thing to consider is they are rubber so will squish up unlike say a trapped gasket.
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Post by headcoats on Sept 18, 2018 9:18:10 GMT 1
I will have to sand down the top surface of the bung then to get it below 1mm Trouble is the casting in the barrel around the bung hole is not even depth, it rises up both sides and slightly deeper in the middle
I haven't touched the the deeper bit under the thinner part of the bung as that looks like it will do the main sealing ?
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Post by headcoats on Sept 18, 2018 9:41:50 GMT 1
This is where I'm at with seating the bungs so far ! You can see they rise up either end but that is down to the casting in the barrels
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Post by wallcraft on Sept 18, 2018 11:40:03 GMT 1
Yep same as what mine were like. I had to get the dreamer out with a tiny ball grinder and fettle metal out to make a deeper apature and take more of the ends of the bungs. Pita!!
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Post by headcoats on Sept 18, 2018 13:02:43 GMT 1
Think I'm going to sand down the 2 high edges either side then the middle down to 1/2mm (sitting proud) all over , then seal them in
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Post by wallcraft on Sept 18, 2018 13:44:43 GMT 1
Yep pretty much what I’ve done, when you’ve done the water test you’ll see no leaks which will give more confidence to get it all buttoned up leak free. Think next time I have mine apart I’ll do what trubrit has suggested. Surprised no one else has chipped in as there’s loads of these top ends on bikes now.
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Post by headcoats on Sept 18, 2018 13:54:33 GMT 1
Yes the info ain't exactly flowing is it !
Perhaps they had such a crap time doing it. they have erased it from their memories LOL
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Post by headcoats on Sept 18, 2018 20:45:14 GMT 1
Now I'm confused ! Trubrit said the water bung was half and half over the front of the cases but just tried 2 sets of YPVS cases one a Brazilian set and the others some jap import 29L stamped cases and the Athena barrels sit flush with the front Are YPVS cases all the same in this area ?
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Post by wallcraft on Sept 18, 2018 21:50:16 GMT 1
You lucky git, there the cases to have for the Athena Top end with out over handing half and half. 350 ypvs cases are half the width were the bung sits. Think the 29L are the ypvs 250 ones. Can I have a set 😊
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Post by jessy03 on Sept 18, 2018 22:01:34 GMT 1
Look same as these 31k ones
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Post by wallcraft on Sept 18, 2018 22:38:16 GMT 1
Confused.com my 31k cases don't have the overhang at the front !! What's going on then?
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Post by LC_BOTT on Sept 19, 2018 7:59:59 GMT 1
I Think all my 31K cases are the 'narrow' type, also have some later 3CE and they are just as the pic. I had the 31K's marked for my big bore set, but might change my mind after reading this. Not the end of the world though.
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Post by midlifecrisisrd on Sept 19, 2018 8:10:37 GMT 1
31k cases did change so may e the front changed too
I'd noticed that lc2 31k cases were different from n/f cases as the later ones has a cut out just behind the coolant pipe for lh powerjet carb clearance
I haven't seen if the front changed though. Only got early cases in the garage
Steve
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Post by headcoats on Sept 19, 2018 8:16:42 GMT 1
Has anyone got a pic of the narrower front cases ?
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Post by wallcraft on Sept 19, 2018 8:29:27 GMT 1
If you go on www.2stroked.com you will see his 421 build with pics of the cases he used, they are the narrow edge type. Good source of info. He's on here regularly as Jonw.
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Post by LC_BOTT on Sept 19, 2018 9:07:46 GMT 1
Has anyone got a pic of the narrower front cases ? Halfway down the first page, nice clear pics I came across a side by side pic a couple of days ago, but can't locate the thread now.
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Post by midlifecrisisrd on Sept 19, 2018 9:31:54 GMT 1
Like this Steve
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Post by headcoats on Sept 19, 2018 9:43:25 GMT 1
Cheers
More luck than judgement I have these type of cases then !
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Post by midlifecrisisrd on Sept 20, 2018 8:55:44 GMT 1
Now stranger than I thought I thought it would be an early/late casing mod so went back through my old pictures The pic is my n1 31k cases which were a late registered model 1985 model, late 1986 registered and they do have the notch for carbs but not the extra barrel area There must have been 2 different companies making them in different casts. Also wouls explain why some have the hole under the sprocket and some don't Steve
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