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Post by unreliablesc on Jul 16, 2007 13:02:39 GMT
How much does a reinforced gear-selector spring do?
I'm riding a mates 136cc these days, and it's jumping out of gear once it hits the power band.
I had a taffspeed spring in my old 136cc, and had no such problems.
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Post by hank on Jul 16, 2007 16:03:41 GMT
didnt know you could get stronger gear selector springs...always thought gear problems like that were worn cruciforms or gears.
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Post by unreliablesc on Jul 16, 2007 16:18:38 GMT
Yeah, you can get harder than std. ones.
I know taffspeed had them, and that W5 does harder ones.
He swapped the whole gearbox for one that looked as good as new, but the jumping didn't get any better.
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Post by MiNiKiN on Jul 16, 2007 16:30:18 GMT
First thing to check is the right play and "centring" of the gears on the main shaft play shall be 0.3 - 0.5mm, but i prefer 0.2mm and do not suffer any such problems (even with worn cruciforms). A stronger spring then might add some safety factor against gears jumping out!
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Post by hank on Jul 16, 2007 17:01:46 GMT
so the gear's 'play' is more relevant than a worn cruciform, interesting
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Post by pj on Jul 16, 2007 21:05:32 GMT
ive had endless problems with my gearbox when i used pkxl2(single push/pull change) cases. i tried strong springs from worb5, but still the gears would pop out racing. then a ss90 gearbox (with the large groves) with the strong spring, it stayed in gear but couldnt hardly change gear. these are all new gearboxes, new cruziforms (ive used 6 now). i gave up, and started a new set of cases, old ss90 cases with the standard two cable gear change to try and solve the problem.
in the mean time i went to a spring making factory and got some stronger springs made. they are stronger than the worb ones (which are just lambretta springs ive been told).
if anyone wants any, when i get some made (i have to get 20 at a time) ill send some over.
paul
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Post by MiNiKiN on Jul 17, 2007 9:10:55 GMT
so the gear's 'play' is more relevant than a worn cruciform, interesting Yes, if the cruciform has contact in the right place why shall it move - to my knowledge there are next to no axial forces. I forgot: I rather use a used/worn Piaggio OEM than a new crap repro. |
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Post by pj on Jul 17, 2007 9:27:22 GMT
so the gear's 'play' is more relevant than a worn cruciform, interesting Yes, if the cruciform has contact in the right place why shall it move - to my knowledge there are next to no axial forces. I forgot: I rather use a used/worn Piaggio OEM than a new crap repro. if you put enough hp through the cruciform, it will bend/twist , and put an angle onto the surfaces that the cruciform mates with the gears. theres only about 4mm of contact thats holding the gear (for each 4 tips) thats having 3-4 times the hp that it was designed for. a even slightly worn, burred cruciform can pop out of gear, no matter how strong the spring is. when i was using a brand new cruciform, new 2nd and third gears and tightly shimmed and the stongest springs i could get made, for the first few races the bike stayed in gear fine. but when you slipped out of gear once, the problems would start. when you miss gears a few more times, i have to force against the cables to keep the gear in the gear. paul |
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Post by tony on Jul 17, 2007 12:22:18 GMT
ive had endless problems with my gearbox when i used pkxl2(single push/pull change) cases. i tried strong springs from worb5, but still the gears would pop out racing. then a ss90 gearbox (with the large groves) with the strong spring, it stayed in gear but couldnt hardly change gear. these are all new gearboxes, new cruziforms (ive used 6 now). i gave up, and started a new set of cases, old ss90 cases with the standard two cable gear change to try and solve the problem. in the mean time i went to a spring making factory and got some stronger springs made. they are stronger than the worb ones (which are just lambretta springs ive been told). if anyone wants any, when i get some made (i have to get 20 at a time) ill send some over. paul hi mate, i'd be interested in some if you do. cheers tony |
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Post by unreliablesc on Jul 17, 2007 14:40:52 GMT
so, i guess we have to take a look at the shims then.
MiNiKiN: centering? you are saying to check for radial play as well?
I have always shimmed my gearboxes super tight (.10 or less) and have had no problems with my smallframes.
I'm interested in some of the harder springs to.
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Post by pj on Jul 18, 2007 8:15:16 GMT
where are most of you guys? uk or the states?
i need to get some springs made up in the next week or so, it will cost me about 100 dollars (mainly setup cost), but they do heaps for that. i will have more than i will ever need.
if there was someone i could send some to, then they can pass the springs around. im happy to post one envelope full only, as im in new zealand.
paul
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Post by tony on Jul 19, 2007 0:23:06 GMT
I'm in uk Paul.
I don't mind despatching them here for people. If everyone says how many they want and how many interested I'm sure we'll sort something out money wise for you.
Just seen the race vid by the way! Have you been on the bsso forum and seen the racing vids from over here?
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Post by pj on Jul 19, 2007 5:48:36 GMT
I'm in uk Paul. I don't mind despatching them here for people. If everyone says how many they want and how many interested I'm sure we'll sort something out money wise for you. Just seen the race vid by the way! Have you been on the bsso forum and seen the racing vids from over here? cool, thanks for the link. paul |
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Post by unreliablesc on Jul 24, 2007 10:25:15 GMT
I split the motor on the 136 yesterday, there was a little play, but way within specs. Gears and the gear selector looked nice.
Replaced the gearbox with the one from my old 136 (taffy spring, and about 0.10mm play). works great now!
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Post by breezer on Aug 11, 2007 14:49:25 GMT
Tony / PJ did anything ever get sorted with the springs, I think I could do with one, brand new cruciform but it jumps out of gear when it hits the power band in 3rd 4th.
Cheers
Jim
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Post by tony on Aug 11, 2007 18:51:53 GMT
hi mate, I haven't heard back from him yet. I've been using mbd lambretta uprated ones-you have to space them tho as they are to short..I used the little clevis pin from out of a prim type front hub link! could have been made for it. If its jumping bad and you've done the usual checks try checking this.. The 6204 hub bearing can wear in its housing on the casing not in an oval way but in depth. So the whole shaft could move in and out with the hub done up tight. Worth a check.
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Post by breezer on Aug 12, 2007 8:53:12 GMT
Cheers Tony.
I wouldn't say it's jumping bad, it happens infrequently. Only in the higher gears 3rd 4th. Fella who did the engine swears the shimming was spot on on the shaft.
He also put all new bearings in so I'm presuming this would't have ahd any play in it, but if so what is the remedy?
Uprated spring can't hurt, it's just a pain that casings need to be split to do it!
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Post by pj on Aug 12, 2007 18:58:44 GMT
sorry, ive been too busy to get to the spring place. ill try and get there this week.
paul
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Post by breezer on Aug 12, 2007 20:07:50 GMT
no worries wasn't hassling, was just wondering!
Jim
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Post by tony on Aug 29, 2007 22:17:09 GMT
Cheers Tony. I wouldn't say it's jumping bad, it happens infrequently. Only in the higher gears 3rd 4th. Fella who did the engine swears the shimming was spot on on the shaft. He also put all new bearings in so I'm presuming this would't have ahd any play in it, but if so what is the remedy? Uprated spring can't hurt, it's just a pain that casings need to be split to do it! if you look on the hub backplate it has a bearing retention lip machined on it. I had less than .5 mm play in mine so i simply leave the gasket off on that engine. If really bad a thin shim would take up the play. Just worth checking where the play is-on the backplate side(change it) or as in mine the motor side. |
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