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the riveted brass cage style that were commonly used by quit a few folks had some failures. crankworks wont even install that kind anymore. seen em fail on single cylinders also dont quote me but i think some of the full circle clips might be slightly bigger diam that 2 oem clips. if the cases wont cinch down this is likely why. cut a few more thousands out of the groove and you be aight or grind the outside of the clip

ive seen people using the roller type with riveted brass cage. personally i would avoid that one and go with one piece steel or polymer cage

you may have just a standard hotrods. seems like i remember them being welded on all the pins

by vacuum you must meen the crankcase pressure has dropped below atmospheric. regarding engines i believe the definition of vaccum is simply any space or void below atmosheric pressure. the exact point when the crankcase reaches negative pressure is hard to say and cant be generalized with all engines. you would have to look at the pipe and its suction ability, how well the exh port and transfers are designed. likely the case comp would be a factor as well. a well designed engine package would reach negative pressure in the case before a poorly designed engine. i know this because alot of poorly designed engines/pipes will allow exh gas to push back into the crankcase for more degrees of crank rotation after the transfers open, obviously this delays the case from reaching negative pressure

bansheehp also said those bearings arent that great so i dont know why your frustration is directed only at me. any monkey can change the outers. to change the inners is another matter entirely, so most people leave them be. you cant expect a $400 crankshaft to have $250 worth of bearings

might wanna get the proper nut with the large shoulder. then use a washer from a yz250. the way you have it now is niggyvered by some drunk redneck

hotrods also uses the same TPI taiwan bearings. for a low budget trail bike i suppose they might be ok but i probly wouldnt use them for anything else. why is the flywheel end of the crank have so much discoloration ? that nut looks like something from the hardware store.

hard to believe its the end of the road with nothing left to improve. maybe new ideas have just dried up

what components does your crank have ? bearings, rods, webs etc ?

i think the smoke test was just to try and get a ballpark visual idea of which way it goes based on the transfer angles. but ya to get a better idea of what happens there may need to be a way to vary the pressure at several different locations like mentioned. a running engine would have varying pressure differentials at the crankcase, cylinder and pipe during each cycle, which seems like it would be difficult to simulate but maybe theres some fancy machines that could do it

tricked this is only my thoughts but for the smoke idea to have any sort of value, i think you would need to test all the transfers at once to see how they influence each other. you can look at the horizontal angles on a cub for example or any cylinder for that matter. testing a single port likely wont give a true representaion of what actually happens, since the trans angles are cast in such a way that they influence the adjacent port. not only that but slow moving air doesnt behave the same as fast moving air around turns and such. how exaclty do you plan to move the smoke through the ports ? dont say shop vac on one end and marlboro on the other

not sure what snomo engines look like but you could tear into any dirtbike from the last 20yrs and not see triple transfers. there was one or two real old single cylinder engines that used them but those ideas were abandoned long ago. if i were to bet money i would say the reason calvins cylinders have 3 transfers per side is for the reason you mentioned. the mixture control into the cylinder is likely better when you have a sqaushed together inline twin design. on a single cylinder or a twin that isnt sqaushed together, its unlikely youll ever encounter the triple transfers

learned along time ago that just when you think ya done everything possible to a engine, theres about 10 more things ya havent tried yet

real mikuni boot http://www.ebay.com/itm/Mikuni-Carburetor-Intake-Flange-VM32-VM34-Snowmobile-Intake-Boot-Genuine-Mikuni-/351206257066?hash=item51c58631aa&vxp=mtr

the crankcase has positive and negative pressure. if there was a leak at the case seam it may pressurize the trans area but once the trans gears churned up the oil it would likely suck in the oil also. which ever side of the crankcase was sucking oil would be smoking. im thinking you have a vent problem. geez its been a while since i looked but isnt there 2 vents that go to a T under the seat or something ?

Chariot has always said he uses mikuni boots on his ebay ads. Mikuni boots say mikuni in bold letters right on the front. Even ray charles would see it. If it doesnt say mikuni then it isnt mikuni

probly made in china like alot of the other ebay shit. if your wanting oem replacments then put oem back on. they last about 10-15yrs

$90 right here is a screamin deal. motor, shaft, peddle, ass load of bits. i dont wanna hear no more excuuses about your stolen tools http://www.ebay.com/itm/Foredom-Flex-Shaft-Carver-Dremel-Drill-Sander-Polisher-Buffer-Tool-Foot-Peddle-/191702464944?hash=item2ca25b79b0

have you looked through ebay. theres a ton of used foredom stuff for cheap. $65-$120 for motor, shaft and foot pedal. brandnew straight handpiece is only $40 to your door. that setup there is worlds better than any dremel you may be using. ive just never heard of any knowledgable tuner grinding casting boogers out of exh ports with a dremel in his free time. dont quote me but ccspecialty might have used handpieces for sale sometimes

i would of never guessed there was a market for cleanups. always figured people want power power and more power

what tools is everyone using ? seemed like camatv has some ccspecialty stuff, probly foredom motor im guessing. i got 2 cc right angles and 2 straights and the motor from foredom. whats your porting tools consist of tfaith ?

if you look at the banshee oem jugs that have boyesens installed some guys angle them downward. some guys just drill a hole straight through. some probly make it more of a rectangle hole and some more of a circle. im thinking there wouldnt be much difference in any of the methods. i think there would be more of a difference between a pencil dick hole and one much larger

what you guys think. strikingly similar isnt the first word that comes to my mind

just happens to be a esr honda cylinder on ebay. can someone point out these striking similarities that tfaith described because i fail to see em http://www.ebay.com/itm/HONDA-TRX-250R-TRX250R-1989-TRX-ESR-RACE-PORTED-CYLINDER-JUG-86-87-88-89-/191697582649?hash=item2ca210fa39

alot of people using near new photos but they send out junk parts. had same problem with minkia. took 3 tries to get a good transmission. one of em had fuked up threads behind the sprocket. my fault for not asking of pic without sprocket. second one was chipped at the end of the shaft where someone tried to hit the waterpump idler gear circlip on with a hammer. seller took the photos at a angle so the damage couldnt be seen. tried to send it back but they would only issue a partial refund