Ned Posted June 4, 2012 Author Share Posted June 4, 2012 I was just gonna use the pressure of the flywheel on the taper to hold it in place and see if thatbworks for now. Quote Link to comment Share on other sites More sharing options...
bubblegoose Posted June 4, 2012 Share Posted June 4, 2012 it doesn't been there fucked that up from memory its about 8' with the common offset keys taking it to 15' so with a bit of slotting of the coil posts and a flipped key you should be able to just get it on the advanced side of life de dum Quote Link to comment Share on other sites More sharing options...
rot808 Posted June 4, 2012 Share Posted June 4, 2012 it seemingly moved when me n dave did this on the iron horse running in reverse on that kids bike, but we never checked properly, could have been other issues, so in summary, this helped you in no way, sorry Quote Link to comment Share on other sites More sharing options...
Yowzer Posted June 4, 2012 Share Posted June 4, 2012 Line up flywheel on crank Apply generous quantities of arc Never remove flywheel again Quote Link to comment Share on other sites More sharing options...
Ned Posted June 4, 2012 Author Share Posted June 4, 2012 I'll see how far it needs to move and go from there. My keys are only 1mm thick so not much I can do Quote Link to comment Share on other sites More sharing options...
Yowzer Posted June 4, 2012 Share Posted June 4, 2012 Those engines already rev quite high don't they? Probably means it has a fair bit of advance, but I dunno how much 2smoke differs from 4 in terms of timing. Quote Link to comment Share on other sites More sharing options...
bubblegoose Posted June 4, 2012 Share Posted June 4, 2012 the bigger 38 to 49cc ones i played with rolled factory 8 and were happy to go upto 25 without making holes in shit i did once breily glance at a 25cc motor on a scooter that was rotary valve and was only just advanced may 1-2degress i always put that down to rotor valves being a cunt to start on a good day Quote Link to comment Share on other sites More sharing options...
Ned Posted June 4, 2012 Author Share Posted June 4, 2012 I had one rev out to 12K on the bench and only played with the two adjustment screw on the carb. Quote Link to comment Share on other sites More sharing options...
Yowzer Posted June 4, 2012 Share Posted June 4, 2012 And the sound of 10 doing that Quote Link to comment Share on other sites More sharing options...
10Speed Posted June 4, 2012 Share Posted June 4, 2012 it's the taper (presuming those have a taper) that holds the flywheel on the crank, the key is just for positioning... I removed the key from my BSA no troubles after 200 miles... however setting the timing 'blind' can be a pain in the arse Quote Link to comment Share on other sites More sharing options...
UTERUS Posted June 4, 2012 Share Posted June 4, 2012 I had constant troubles with timing moving on my tru test with offset key, I got angry and loctited the cunt in place. Quote Link to comment Share on other sites More sharing options...
Ned Posted June 4, 2012 Author Share Posted June 4, 2012 All those flywheels had to be preyed off with a hammer and screwdriver, thats how well they hold on with just pressure. Loctite sounds like a nice addition though once i get the timing about right Quote Link to comment Share on other sites More sharing options...
KIRK Posted June 4, 2012 Share Posted June 4, 2012 the flywheels will move without a key. They shear keys sometimes and move so yeh without a key iduno. Do these have the 'key' cast as part of the flywheel or a normal steel key? do your engines have a threaded bolt type crank pin that screws into the crank or is there a circlip to hold the big end onto the crank? do your engines have offset pistons? can you rotate the barrels on your engines 180 degree and if so, do the transfer ports in the barrel line up with the start of the ports in the crankcase(assuming this is how they've worked it on royobis, i've never looked inside one)? Quote Link to comment Share on other sites More sharing options...
Ned Posted June 4, 2012 Author Share Posted June 4, 2012 9/10 have a normal key. 1 has the key cast into the flywheel. No idea about any of your other questions Quote Link to comment Share on other sites More sharing options...
KIRK Posted June 4, 2012 Share Posted June 4, 2012 i was just wondering about how they will actualy hold up to running in reverse. if they have a screw in crank pin that the bigend rides on then it may undo(it will be right hand thread if it is, i duno if this will actualy be a problem i was just wondering). If the crankpin is part of the crankshaft and the conrod is held on via circlip then it wont matter. I've seen it done both these ways on half crank engines. if the pistons are offset then um.... google...wiki explains: There are serious disadvantages to running any engine backwards under load for any length of time, and some of these reasons are general, applying equally to both two-stroke and four-stroke engines. Some of this disadvantage is intrinsic, unavoidable even in the case of a complete re-design. The problem comes about because in "forwards" running the major thrust face of the piston is on the back face of the cylinder which, in a two-stroke particularly, is the coolest and best lubricated part. The forward face of the piston is less well-suited to be the major thrust face since it covers and uncovers the exhaust port in the cylinder, the hottest part of the engine, where piston lubrication is at its most marginal. The front face of the piston is also more vulnerable since the exhaust port, the largest in the engine, is in the front wall of the cylinder. Piston skirts and rings risk being extruded into this port, so it is always better to have them pressing hardest on the back wall (where there are only the transfer ports) and there is good support. In some engines, the small end is offset to reduce thrust in the intended rotational direction and the forward face of the piston has been made thinner and lighter to compensate - but when running backwards, this weaker forward face suffers increased mechanical stress it was not designed to resist.[9] Hence investigating if its possible to rotate you barrels and pistons theres only one way to find out how they'll go i guess edit: wait ignore all of that, i see your exhaust ports are on the back side like tecumsehs and i doubt you got offset piston. Will be sweet. i was thinking your engines would be the same design as my panda bikes but they are not at all. Quote Link to comment Share on other sites More sharing options...
Ned Posted June 4, 2012 Author Share Posted June 4, 2012 Yeah, i read similar things. But at this point i'm going with the 'ignorance is bliss' philosophy haha. I'll just try get it runningand cross that bridge when i get to it. The motors all have bent cranks as well and don't like spinning end on end as they now wobble... this will probably be the biggest real problem that i'll habe to worry about and i'm not even worrying about that at the moment. Cheers for the pointers though! but we'll see what happens if/when i fire it up Quote Link to comment Share on other sites More sharing options...
KIRK Posted June 4, 2012 Share Posted June 4, 2012 nah ignore what i said, i should have looked at a picture of a royobi first. I was imagining engine like a half crank victa or my panda bikes chinese thing which is like a super small victa. Quote Link to comment Share on other sites More sharing options...
Ned Posted June 5, 2012 Author Share Posted June 5, 2012 New sprocket ordered. Will be here tomorrow so tonight will be doing the last of the plate modifications Sprocket cost $29.00 though!! well, $14 + $15 for the machining. Will do the machining myself on the other sprockets Quote Link to comment Share on other sites More sharing options...
Steelies Posted June 5, 2012 Share Posted June 5, 2012 yeah boy! Quote Link to comment Share on other sites More sharing options...
anglia4 Posted July 21, 2012 Share Posted July 21, 2012 Does it have a prop yet? Jokes... any progress? Quote Link to comment Share on other sites More sharing options...
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