blowit

The stockers are about a 7mm wire. you can fit 8mm, and 9mm with a lot of work. What we have done in the past is mfg tube collars and swedge the end to make them stay. B

Yes, there is some spark energy to be gained by using different plug wire, coils, etc. My common configuration is OE coil with larger, low resistance wire and a resistor type plug (BR8ES). The resistor plug seems to suppress enough back voltage to protect ciruits and the lower resistance wire will transfer more energy from the coil to the plug. Remember that V=IR. Also remember that voltage is what jumps gaps, not amperage. Brandon Mull Engineering

The reeds will not cause your change in compression. More than likely a piston/ring issue here. Brandon Mull Engineering

If the bearing is failing, it would cause the shaft to spin in the inner race. They are not a press fit into that bearing. Just pops in. Brandon

In our experience, the oils from the filter and the moisture from sand can eb enough to cause issues. Honestly, if the outerwear if cleaned religiously, it works as designed but many people ignore them and don;t realize the power being lost. Brandon

They reduce flow approx 10% when clean but can be as much as 50% restrictive when dirty. If any moisture hits them at all, They plug up. We have had big problems with riders in wet grass. The pore network of a gauze filter allows decent flow when dirty compared to the outerwear. Brandon

We have never had anyone lose a set. I run them in the dunes all the time. We use a very heave clamp kit. You would be surprised how rigid they are. I do not sell the outerwears for these because we have learned that they actually cause more problems than they prevent and we have 2x the number of pleats on the filters to work better for off road use. If you really want outerwears, they are available in this filter size from outerwears. Brandon

I will say that tuning is everything on carbs and probably 50% of bikes out there are missing some serious power due to tuning issues. I am not sure what you are running now for an intake kit but I know we have never found anything else that will flow more air than our kit on stock carbs. They breath the same as a 29mm carb IIRC with the kit installed. Bigger carbs are always a consideration but many people like to keep the responsiveness of the stock carbs. Brandon

Stock carb is a 26mm and is bore limited by the diameter of the slide valve which is 27.50mm. Regardless of what you read, you cannot take them past that point or they will have a nasty air bypass condition that is sure to give you huge headaches. We have stopped boring the Banshee carbs because the return for our customers just is not there unless racing in a specific class that requires stockers. You can apply some taper boring or venturi work on the back but we decided to develop a venturi intake/filter kit instead as it was hitting several birds with one stone. Brandon Mull Engineering

I don't see anything that is alarming and should give you some more power. Make sure to chamfer all your ports and then hone the cylinder bore when you are done, in that order. Failure to properly chamfer ports causing piston failures and eventual piston mfg blaming.. Good job.. Brandon Mull Engineering

No, arcing is not a normal condition. Not really sure where you are experiencing this arc but wondering if your grounds are no good thus causing the fly wheel to try and reach a ground loop through the PG. The PG does not make enough power to build a health blue spark. I would pull the flywheel and stator and see if you can determine the origin as well as test all ground points. IF not, the stator will surely die very soon. Good luck! Brandon Mull Engineering

Likely that the shift shaft claw has jumped off the shift star. Very common issue. We also developed a fix for it but you may also be able to adjust a few things to get it to stay on better. The shifter will typically not return with a spring like feel if this is your issue. http://www.mullengineering.com/sc/store.php/products/yamaha-banshee-billet-shift-star-431 Brandon Mull Engineering

Yes Kev, that line most certainly will end up in someone's sig.. Guys, the impeller head can either be pressed or simply smacked in with a hammer. We planned it that way because we know not everyone has a press in their garage...We do not put a large amount of interference on it because the end of the stock shaft is splined and locks up nicely. Our torsion testing proved our designed fit would basically break the impeller before it will slip on the shaft. They go together pretty easily. Brandon

Numbers from the piston or measure the bore with a caliper. A caliper is not sufficient to properly size the bore but good enough to help you decide on a head gasket. Brandon Mull Engineering

The price is 33.99 for this part and is listed on our website. If I would have known we were getting such an upclose and personal pic, I might have sent a prettied up version..... Brandon Mull Engineering

I did stumble onto our tech data for that gear this morning. We have the OEM gear weighed at 16 grams and our billet replacement gear at 34 grams. This a little over a 1/2 oz more weight if someone is counting.. Thanks Brandon Mull Engineering

I would tend to agree. We have used plenty of WSM pistons. Many times we find that if pistons are installed incorrectly, with the wrong tolerance, or with bore problems, the piston is likely blamed. To this day, we have yet to have a failure from WSM pistons. WSM, where is my check???? Regarding the compression issue, you might take a read of an article I did a while back regarding compression testing. http://mullengineering.com/rt/support.htm Brandon

That is of course unless there are big bore sleeves in the stock cylinders. It might be best to check the size on the top of the pistons first. 66mm is really the largest size piston you should use with a standard head gasket. The larger sizes will use a big bore gasket. Brandon Mull Engineering

A 392 is a stokc stroke, 68mm bore engine. You will have problems adapting the porting of that cylinder to a 5mm crank. You timing is already very close to drag spec and adding the 5mm crank will put you well outside of "my" optimal window of performance. If you were adding the 5mm crank to a 58mm stroke cub, that should prove a pretty easy and worth while swap. If you do add a 5mm crank to a 54mm stroke cub, let us know how it works out.. By my numbers, no one will be home till about 7k rpm wtih a nasty back draft in the transfers. Of course it is possible that I am missing something in the setup you are talking about.. Brandon Mull Engineering

If this is for pavement drags, there is no replacement for displacement. If you are closed course racing, the PV will win every time through a controllable power band. Brandon Mull Engineering

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Let me save you the trouble and I will come pick it up tonight... Really though, if you want to dump it, I might be interested. I am in Wichita. Lemmee know... B

That oring letting go is likely giving you fair warning about an engine problem. Likely that is it toasting on the exhaust side of the dome. If you are running out of fuel, you should address that issue and it should fix the problem. Standard Orings will typically hold an alky 16:1 motor. I would recommend studying fuel flow restrictions first. I have been able to run some pretty hot motors without a pump but reducing restriction. B

Dieseling is actually a totally different phenomenon. This just sounds like the timing being far enough off to reverse the engine which is certainly possible. Dieseling refers to a type of compression ignition cycle. Brandon

Just another thought. I think the 24VAC solenoid might be the way to go. It would eliminate the need for the rectifier circuit so you would only need a 24VAC regulator. This would keep voltage drop to a minimum. Keep in mind that this voltage will not be seen at idle if that will be a concern. If you need idle performance, you will want to add a battery and DC circuit for consistent performance.