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Banshee building questions


SprayBomb

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Hey yall, my name is Matt and I have some questions about building a banshee in basket case form

 

For right now my main questions have to do with the engine

The engine for sure needs a top end, the jugs are loose, one piston removed and the side cases are off

 

I'm completely new to owning a banshee and what to look for / do when it comes to what is needed and not

 

The jugs are stock and in good shape, but I haven't mic'd them to see if they have been bored

The pistons are a lil brown under the rings so I'm sure the rings were gone and that's why it was torn down

 

It's missing the flywheel, so am I better off getting a stock used one or a new one (if new, any particular brand)

Also the clutch basket has some rotational slop between it and the gear, I have read that there are rubber "bushings" that are the culprit, but am I better off buying an aftermarket basket or to replace the bushings?

Also I have no discs for the clutch, so what would be a good choice for a mostly stock trail ridden bike ?

 

Since I know nothing about this engine I'm curious about the bottom end, I don't want to put a top end on it and the bottom end be bad or blow shortly after, so am I better off to split the case and rebuild the bottom end too

And if I need to go into the bottom end, what do I need to look for when it comes to wear, and am I better off sending my stock crank out to get true'd and welded, or buy an aftermarket crank

 

I do mostly trails and just general screwing around, so I'm not trying to build anything insane, but I do have an insatiable crave for power and am a pretty big guy at 6'6" and around 280

 

I would like to send the jugs off for trail porting if I can afford it

I already have a cool head, and a set of FMF Golds, but really would like some PT Hi revs if they won't completely screw my powerband as I love the hit of a 2 stroke

 

I haven't really found any good FAQs or beginners banshee engine building threads, but if you have a good link for me to read I'm all for it

 

In short, what are some key things to look out for and what should be an automatic upgrade since I'm building from scratch

 

Thanks, Matt

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You're definitely going at this with the right approach. Read, read, read, there's tons of info that will give you plenty of ideas on what other people have built, mistakes they have made, and the consequences. Here are some of the basics.

Buy a Clymer manual.

Definitely split the cases and build a good bottom end. There are tons of choices depending on how much money you want to spend. tru and weld stock crank, rebuild stock crank, new stock stroke crank, new 4 mil crank, etc.

Definitely buy a used OEM flywheel. Aftermarkets are junk

Definitely buy a billet clutch basket.

 

So, the short version is send your crank and cylinders to a site sponsor or send your cylinders only and tell them to port for 4mil and ship them back with a 4mil crank, pistons, and domes. Everything else, you can assemble yourself.

 

Here's the bottom end assembly walkthrough, so you have an idea what you are getting into.

 

http://bansheehq.com/forums/index.php?showtopic=140912

 

Some of the basic tools you need to own are, flywheel puller, impact driver(The kind you smack with a hammer), carb sync tool, leakdown tester, and compression tester.

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The Banshee crank is a multipiece crank, press fit together. Welding keeps it from from spreading apart and twisting at the pins.

As far as a builder, all of the site sponsors are good. Some slightly better than others. Read, read, read, and pick one. Especially check out the Dyno Room.

http://bansheehq.com/forums/index.php?showforum=55

 

 

 

BansheeCrank1.jpg

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115 rod adds leverage to the stock stroke, and runs real good for the level of mod that it is. You need to either compliment it with a Blaster piston (your head needs a bit of work for this), Or there is a Wiseco piston that compliments this long rod-ready to go.

 

Getting the crank trued is VERY important on the 'shee engine. It turns very high RPM's and even a bit of run-out turns it into a "bearing eating", power robbing, quick wearing parasite!! The book specifies how much run-out is acceptable (key word ACCEPTABLE) Nothing leaves my shop more than .0015-and 90% are less than .0005. And any other builder here, on HQ, is probably just as meticulate. Even a newly purchased crank should be checked out (I have unboxed some scary stuff in the past-haha)

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star said it best.  get a book and start reading.. do everything he said ....  i'll add this.

 

matton plated basket one of the best for price and strength there is.

 

tusk complete clutch OR FAST clutch.  one is 55 bucks  other is around 120ish>?  ebc is a good clutch also.   do you have all the componets, pressure plate hub etc??  also get a bearing clutch pusher for it  cheap insurance.

 

have someone look at the cylinders and see what you have there for sure. after that you can kinda get a plan together for the complete motor.

 

 i personally use only cometic gaskets AFM style, OEM crankshaft seals, and OEM clutch cover gasket.  best to check the water pump and most likely replace the seal in there also.  any other aftermarket complete seal kit for the rest seems fine  i just don't like most others crank seals.  some are total trash. 

 

also while your in there look into doing a stock modified transmission  if you want more info on the one i offer  send me a PM.  

 

the truererrrer  the crank is  the better it will run.  i have also seen some only weld the outer pins and the center go out of phase and then separate also.  bad day... even an fmf trail beast 350 will need a welded crankshaft/

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that sucks!

 

hardware is not as hard as you think to get.   you can check ebay and look for salvage places stripping them down.  most of them will have a complete engine bolt set or every bolt removed from the outside of the bike.  just get a few of those and you should be set.  alo i have used hardware stores for most of the outer bolts on the chaissis and such.  ace has a lot of metric flanged bolts in a grade 8 setup and matching nuts.   the "wife's bike build" i used that style of hardware throughout it  they are silver plated in color also.  that was the main reason. i personally never really liked the stainless bolt "kits"  the stripping and siezing and all that dang antisieze goop all over them just turned me off from that stuff

 

i'd also recommend getting the allen bolt kits for the clutch cover and the stator cover  those are cheap and work much better than the screws.  matton sells them.

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