OZ ATV :: The Australian ATV Forum

[RMCprime]

Hi everyone,

My brother overheated his banshee/yfz350 and as a result it is seized. It can be kicked over at all. I suspect it was running lean on one cylinder as the FMF pipe on that side is deformed where the pipe diameter is at a maximum. We are pretty keen to rebuild it.

I'm fairly handy with the tools and have a Clymer repair manual for it. We are intending to pull the motor out in a couple of days to see whats rooted.

So I'm just after some info on what parts are good for the rebuild and if there are some parts you guys recommend for a mild performance increase. I've had a quick brows through the other threads and seen mention of vforce 3 reeds and long rods.

I'm new to this so excuse me if I ask some stupid questions.

thanks

[greenhuman]

Can it be turned over? I don't understand that part of your post. If it can, leave the engine in the frame and take the top end off. You can check the crank when the top end is removed. Doing it this way might save time.
If it is seized solid it is more likely to be the crank locked up or a piece of piston jammed between the crank wheels and the cases.
The exhaust would have to be really bad before it would lean out a cylinder. Banshee's have a habit of leaning out one cylinder because of the T piece fuel line. When going flat out in one direction like on a speedway or sliding in the sand, one carb doesn't get enough fuel because of the centrifical effect.

[RMCprime]

Sorry. Bit of a typo there. It can't be turned over at all.

The left hand exhaust pipe is a little bit buckled as if its been heated with a blow torch. I was using the heat deformation of the exhaust pipe as a sign that it might have been leaning out on that side. If it has been lean on that side I'd expect the piston to be damaged.

Is there a way to run two seperate fule lines to negat this t-piece problem.

So far from the reading I've done I'm looking at getting.

Crank... Not sure on brand or type
Wiseco pistons... What size?
Long rods...Not sure on brand or type
Vforce 3 reeds
Head... Not sure what type
Machine current cylinders if in decent condition

I need some help.

[4stroker]

pingel dual fuel valve gets rid of the t piece

Crank... Not sure on brand or type
Wiseco pistons... What size?
Long rods...Not sure on brand or type
Head... Not sure what type
Machine current cylinders if in decent condition

once you have decided on the crank, that will be the basis for choosing the rest of the parts for your build

CRANK - for example, a "wiseco hot rods" stroker crank with long rods isnt much dearer than a stock stroke crank (probably $75?)

RODS - rods come with the crank. if you get long rods (and if you get stroker itll def have long rods) you need the 795 series pistons so you dont have to run a spacer plate. what size you get depends what bore size you are at now?

HEAD - get a noss machine or pro design cool head with removable domes. if you get a stroker, your new head will need stroker domes to accept the extra piston travel. if you dont get a stroker, get 19cc domes and run 98 octane fuel

CYLINDERS - machining your current cylinders will depend on what size they are at now.

what you need to do first is take your cylinders off and get a engine machine shop to measure what bore they are at. then buy the next oversize Wiseco piston kit (once you have decided what crank combo you r using)

then you take your new pistons and old cylinders into the machine shop and they measure the new pistons and bore and hone your cylinders to suit. make sure they add 3.5 thou bore clearance for wiseco's

and if you get a stroker crank you will need to grind the ports 2mm lower in the barrels as well.

oh and get an adjustable timing plate and set it at plus 4.

add a new pipe and hang on tight!!
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2002 SE Banshee

[RMCprime]

Ok. I went to the shop online section on the Wiseco site just to get an idea of the price.

1x WPC129 - Crankshaft Asmbly-Banshee LR Stroker ...$650.88
2x 795M06450 - BANSHEE LONG ROD 2539CD (64.5mm piston)...$226.82
2x 2539CD - 64.50 MM RING SET ...$67.08
1x W6093 - Gasket Spacer Kit - Banshee 4mm Stroker...$85.46
total...$1030.24

That I guess is in US dollars and doesn't include shipping. So i think I'd be looking at similar prices if i get it through a dealer in AUS, or should i get it straight from Wiseco.

All Crankshaft Kits include: Connecting rods, Main Seal kit, Main Bearing kit, Gasket kit & Top End Bearings

Above where it says the crank kit includes a gasket kit. Does this mean a complete gasket kit or just the bottom end kit?

The top end gasket kit for the LR stroker says its a spacer. Is there anything wrong with using the OEM head and the spacer kit? Probably wont have money for a head upgrade on top of that for the moment.

Also will I need to replace the gudgeon pins and clips? I was thinking that if the current pins fit the new pistons and are in decent nick I'd re-use them.

Cheers for the help

[4stroker]

you may not even need a crank, have you had a look yet?

it could just be the piston and rings stuck in the barrel causing it to not turn over.

although if it was hot enough to deform the exhaust id say theres a 50/50 chance something has dropped into the bottom end.

OR if it was that lean, you may have damaged the big end and main bearings. once you have it apart your clymers manual will tell you how to check the crank to see if its any good. (rod clearance, side to side and end play)

for starters dont go straight through wiseco. believe it or not the prices are alot cheaper through retailers in the states. its because they get such a big discount buying in bulk i assume. the crank should only cost about $550 and the piston "kit" $200, which consists of pistons, rings, pins and clips.

if you dont want a new head the spacer will be "ok". but, it will raise all your ports by 2mm, taking power away from the bottom and adding to the top. this will be offset some by the longer stroke but not much.

then, at BDC, your piston is 2mm lower thanks to the longer stroke, and your barrles are up 2mm thanks to the spacer. if you dont get the barrels ported so that the ports line up with the top of the piston at BDC, they will be 4mm out. it will run ok like this, but it wont be to its full potential and it could prove difficult to jet.

if you do grind them and then later on decide to get the head with the stroker domes and lose the spacer, you will have the opposite problem, with the piston covering the ports at BDC. this will also not be optimum and be difficult to tune.

if it were me id wait another pay cheque and get the head and domes right from the start, dont get the spacer, and get someone to grind the ports to match the crank.
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2002 SE Banshee

[RMCprime]

Well we have covered the stroker option.

What are some options to increase performance using a standard rebuild kit.

I must say I appreciate all the help I've been getting, considering I'm a newcomer

[4stroker]

hey mate

for standard rebuild, get some Wiseco Pro-Lite pistons - $200

you already have pipes, so:

1. shave the head 20-25 thou, - $50 at local machine shop (whoever bores your barrels should be able to do it)
2. get a timing plate and set it at +4 - $80
3. get a billet filter flange and k&n filter and run no lid (depends where u ride i guess) - $200?

jet it to suit

that there will get you a healthy low to mid range increase and really wake the bike up

v force reeds would probably be your next mod, but they are about $450-$550 depending where you get them from

after that some porting, work on about $600 for a good port job on both barrels if you dont do it yourself

after that a new carb/intake setup, the style of power you want will be the deciding factor in which carbs to get

after all that, you stroke it

if you still want more power, get an aftermarket top end

if you still want more power, get aftermarket cases and bigger top end

if you still want more power, get triple cylinder cases and 3 top ends

if you still want more power, get 4 cylinder cases and 4 top ends

see where this is going? lol the sky is the limit with what you can do to the banshee
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2002 SE Banshee