firebanshee

I like my metal tech a arms and swinger :cool:

I would run a 13 -41, if you weigh alot you could run 13-42 or 43,dropping 1 tooth in the front sprocket is like going up 3 in the back.

21cc dome at sea level is safe for 93 octane pump gas, anything smaller than that at sea level you need to start mixing race fuel with 93 octane and about 19cc dome at sea level you should start running straight race or av gas 100LL. But if your bike is bored out bigger that also plays a role in your compression because your are commpressing more air with a larger cylinder.I have found that if your bike is bored to 100 over running a 22cc dome is like running a 19cc one a smaller bore motor.This only applies to small bore domes.Just my expierence not an exact science though.

JJ&A all the way :cool:

That depends on if Bill has CPI's LOL :biggrin: :biggrin: I don't know :biggrin:

Choke tube on? the 2 1/2 inch hose that hooks between the carbs.

yup :cool:

Banshee case assembly As always, you should refer to your manual for specifics of your model, this information is suggested as a supplement to a full manual. Parts diagrams are available at Yamaha's website, don't hestitate to look up your model to make sure you have all the parts required in position. The cases shown are worn Banshee parts used for demonstration. Prior to assembly, thoroughly clean cases of any oil, dirt, or grease, and scrape the mating surfaces and gasket surfaces with a razor blade or gasket scraper. A wire brush in a drill works well to remove case sealer and gasket particles. Inspect all threaded holes and studs, and make sure both front and rear locating dowels are in place, as well as bearing locating clips. Place a few drops of 2-stroke oil on the seal lips, and place them on the crank and transmission shafts. The drive side crank seal should have the castellated nibs facing the bearing, the ignition side seal may have "outside" marked on it, but if it does not it can go on either way. The output and clutch pushrod seals should have the flat surfaces facing out. The crank bearings should be left dry at this point to keep the case sealing surfaces clean, they will be lubed after assembly. Coat the lower case half with case sealer. I prefer 3-Bond 1211 white silicone, Yamabond or 3-Bond 1104 is also acceptable. Place 1 or 2 drops of red or green Locktite or equivalent on the bearing surface of the lower case for each crank bearing and the countershaft bearing, then spread it evenly across the bearing seating surface. Install the transmission in the case, making sure to align the shift forks with the corresponding gears. Observe the locating pins on the crankshaft bearings, and position them all in a line. Lay the crank in the case half, with the locating pins in their corresponding indentations in the case, and the seal ribs in the grooves in the case. Tap the crank down tight with a plastic hammer or wood block, checking to make sure the pins are properly located and the bearings and seal seated. Place the top case half on the lower half, and install the upper case bolts. Tighten them just enough to pull the case halves together, then stand the case up on it's rear end and install the lower nuts. Tighten them in sequence, from inside to outside, in 2 or 3 steps until you reach a final torque of 18ft/lbs. Then tighten the top bolts to 9 ft/lbs or hand tight. Make sure the crank and transmission shafts turn freely, and the trans shafts should have about 1mm of end play until the clutch and counter sprockets are installed. Just prior to installing the pistons and cylinders, place a couple drops of 2-stroke oil on the rod oil slots and thrust washers, and a few drops down each main bearing lube hole in the transfer cavity. Also oil piston pins and top end bearings prior to installation. I put just a drop of oil on the piston skirts and wipe it over the surface. Use Locktite on screws for the clutch bearing retainer. Install kick idler gear and kickstarter, making sure the spring tab is inserted into it's slot in the case. I use a very thin film of 1211 silicone on the flat surface of the primary drive gear, to make sure it seals against the crank bearing. Install the clutch washer, sleeve, basket, inner washer, and hub, followed by the clutch plates. On steel plates with a cutout on the outside, stagger them so they are more or less evenly spaced around the clutch assembly so the clutch remains balanced. (The cutouts are to allow the plates to sling out on the heavy side so they don't vibrate against the hub). With all the plates installed, and Locktite on the threads, it is easy to hold the clutch assembly by hand so you can tighten the crank and clutch nuts with an air or electric impact. Be sure to index the clutch pressure plate so it engages the splines of the hub, and use only hand tight on the spring screws, never an impact.

Place a few drops of 2-stroke oil on the seal lips, and place them on the crank and transmission shafts. The drive side crank seal should have the castellated nibs facing the bearing, the ignition side seal may have "outside" marked on it, but if it does not it can go on either way. The output and clutch pushrod seals should have the flat surfaces facing out. The crank bearings should be left dry at this point to keep the case sealing surfaces clean, they will be lubed after assembly. I found this on line, I also like to pack the seals with grease to keep the springs from falling out during assembly.

Are you done yet :biggrin:

I run 1 pint to 5 gallons of fuel.

Spacer plates SUCK!

I am a fan of fat bastards, but that is probably because i am one :biggrin:

You made a good choice buying a welded crank since it is the heart of your engine.I see alot of people on here doing alot of mods to there bike without welding there crank and they are asking for trouble. :cool:

Here is a link to a calculator to figure engine size. Link to engine size calculator

I have a buddy that has ran his 100 over cylinders for 3 years no problems, alot of drag racing and hard dune riding.At those bigger bores you have to run a little bigger domes to keep your compression in spec. I think he uses a 21cc with staight av gas.He had a 19cc when he first put it together and it had about 225 to 230 pounds of compression :cool:

I use to run a 4mil short rod crank and it did rev up faster but, i also use to break alot of piston skirts and even broke the bottom of my cylinder liner. I will never run a short rod stroker again, it was pretty quick when it was running.The added stroke of the crank amplifies the side loading of the piston.And as stated in the prior post short rods use stock pistons and you still need cut domes, i would not use spacer plates.

No, i have used both resistor caps and plugs and it worked with no problems. I have read that you need at least one or the other. I know that it stops electrical interference using resistors and have read that it can harm the cdi without one. I have also used just resistor caps and non resistor plugs with no problems.

I found this on NGK's website you need a 5k ohm resistor style here is the link NGK's parts list for plug caps

I get mine from my local bike shop, i do not have the part # , maybe HERR or FAST has them.You can use the ones that don't have resistors built in them but if you do you have to make sure to use a resistor style plug like a bR8es instead of a b8es, or it can damage your cdi. I use the resistor style plug caps myself.

Any good motor builder will answer all your questions and will port and build your bike accordingly,they will tell you what pipe carbs and timing and compression and everthing esle involved. DON'T go cheap on your port job it is EVERYTHING when it comes to a 2 stroke.

Alot of guys on here use KEVIN from HERR or JEFF from FAST, both site sponsers. I use a local guy out here in Oregon, CAMERON from REDLINE.They are all good builders.

You should talk to the guy who is going to port your motor, a good motor builder will set you up for your riding style.

What kind of fuel do you want to run? 93 octane, some type of race fuel, to run pump 93 octane at 450ft you should stay around 21's.

I leave the edges sharp but i grind out the half moon part a little wider and deeper.