blowit

Not quite accurate. Stroking and port duration are not related in a linear manor. There is around 10-15 degrees difference between the stock setup and the one you describe. Brandon

The book is wrong. The reason the trans does not shift properly on the bench is because it is a sequential constant mesh trans that needs to be loaded to feel right. If you can twist the drive and driven shaft in opposite directions and get it to fall into gear, it probably fine. If you cannot get any gear changes at all, that IS a problem. brandon

So you are wanting the barrel length? Curious why you want that? The ports should be different if used with a spacer or not. Brandon

Move to the carb because ignition is not the problem. You have already replaced the major stuff and the reg will not help. You have something else going on. Brandon

Ratio would be 6.4:1 Brandon

What, you don't have precision vision?? That reminded me that we had an engineer one day that said you cannot even see .001" or something along those lines. We proved him wrong... I would agree though, measuring trumps " it feels pretty good" any day. Sometimes looks can be deceiving. Brandon

Well that cylinder is not running and you need to figure out if it is fuel or ignition related. I would think you either lost compression on that cylinder or something clogged up the carb. If you put a new plug in and swapped wires and that did not fix it, it is not ignition related. Brandon

Post your port heights and I will tell you what will work best for a 4mm crank. Brandon

I disagree that is is a crap setup. It works exactly as intended. If you are running a mostly stock bike, there is not reason to remove them unless for cosmetic reasons. They can save your ass and banshee carbs are notorious for sticking open. Most people that have "problems" with them most likely have cable or tuning issues that are remedied with the TORS eliminator kit. We generally remove them but there is no good mechanical reason to. brandon

Listen, the correct and only way to check your bore is with at least a dial bore gauge and set of mics. Since you will likely not own these, it is best to allow a pro to check the bore dims. Feelers and "checking slop" simply are not good enough. I would bet the bore is worn out and you may have installed new pistons in a worn hole when they broke. I would say, with most certainty, that a fresh bore and set of pistons will fix your problem. The rings are no indication of piston wear whatsoever and if you intake ports are not chamfered, it can cause skirt damage but will rarely break the piston. This looks like a classic case of "worn out bore". Brandon

They are not hitting at the same time, one is not hitting at all. Most likely a carb balance problem. Check the sync and make sure the choke tube is on. Brandon

Post up some pics so we can see. There ARE critical dims that must be adhered to or you risk junk cylinders. Post up your port durations and port/time areas and we will go from there. The only way to ensure uniform flow between cylinders is a flow bench. Two strokes require very special adapters for such testing to isolate critical areas of flow. Brandon

Your motor guy is on the right track. The best trans in the world will not hold back an abusive shifter foot. Depending on how long it has been like this, you may get away with just the fork. Remember to replace the fork shaft. Brandon

Post pics of the ports close up. That will be a god start. Brandon

Sounds like a porting or port chamfer problem. Brandon

I would say you are fighting carb issues and they are not perfectly synced and the idle set is not right. If you can pull the choke lever when the RH cylinder drops out and it will pick back up, it is carb related. It is possible you either need to adjust your air screws or raise the pilot jet to allow more fuel in cold start conditions. brandon

When I say coil testing, I mean all stator coils, and ignition coils. You need have a meter this. Also, inspect spark for blue color. Orange is not good. Brandon

As long as the bore is within tolerance, you should be able to install new pistons and roll on with a good hone. Brandon

Yep, take it apart. broke skirt or lodged reed. Brandon

All the things you are describing are pointing to a weak ignition system and not jetting. The banshee produced a weak spark at kicking speeds but you should feel it. I would start with continuity testing and see if the coils are ok. The pulse generator will not affect the quality of spark. Think if it as a trigger. If it is too far from the flywheel, it will not initiate spark but will not cause weak spark. DO NOT put #7 heat range plugs in. You have a problem and the 7s will not fix it. Start with that coil testing and report back. I am suspecting either bad plug caps or stator. Brandon

Wow, you seize them and roll on?? Ouch, our customers would be pissed. Brandon

Yes it can be done but with much difficulty. Reasoning is because of excessive port timing that will always be a problem. Just fitting the stroke in the hole is a small part of the equation. Basically, to make it right, the ports need to be relocated for the different stroke. I highly recommend aftermarket cylinders for that much stroke. Brandon

.7500" Brandon

Yes, it can be replaced and the rod should be replaced as well. An experienced machine shop can do it. You should look for a bike shop to do this work if possible. As long as tolerances are observed, should be good as new. Brandon

Good deal, glad you did not pull your crankshaft and inspect the muffler bearings to find it. I would think that when your carb top came loose, it allowed over travel of the slide and it hung up on the alignment pin. Keep them tight and you should be all good. Brandon