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  Topic Review (Newest First)
01-13-2020 11:32 AM
CAM2
Re: Pinion and Chain Interference

Quote:
Originally Posted by pntrbl View Post
Happy Day! My 8T pinion arrived from China in a very reasonable amount of time and it does fit a T8F chain just like the the seller said. The larger dia of an 8T vs a 6T solves the clearance problems I was having too. Thank Goodness something finally worked. I was beginning to get nervous.
Happy Day indeed and Awesome to hear ..………...
01-11-2020 10:45 PM
EPR
Re: Pinion and Chain Interference

Some of the people on that eBay add, were selling showing #25 pinions with 8M and 10M which is the thread size its confusing people. Glad it worked out for you. Once again CAM2 comes thru.
01-11-2020 08:36 PM
pntrbl
Re: Pinion and Chain Interference

Happy Day! My 8T pinion arrived from China in a very reasonable amount of time and it does fit a T8F chain just like the the seller said. The larger dia of an 8T vs a 6T solves the clearance problems I was having too. Thank Goodness something finally worked. I was beginning to get nervous.
01-05-2020 12:52 AM
EPR
Re: Pinion and Chain Interference

Kind of like this set up. The heads face backwards cause the transmissions turn backwards, really for a piston port engine. This set up drives with the chain on the left side of the bike.
01-04-2020 09:38 PM
pntrbl
Re: Pinion and Chain Interference

Right now I've got my hopes pinned on the Chinese guy you found CAM. Hopefully he knows what he's selling ...

https://www.ebay.com/itm/6-7-8-Tooth...72.m2749.l2649

And I may have got the last one! His listing only has 7 teeth available now.

But if I have to I'll make that double D 9 tooth work. I got a welder. Thanx for pointing it out.

The 3:1 box showed up almost overnight and while it did have a 9T pinion it's a #25. No help there.
01-04-2020 01:21 PM
CAM2
Re: Pinion and Chain Interference

Quote:
Originally Posted by pntrbl View Post
Something's gonna work! Right now I got a 3:1 box scheduled to be here Monday and I'm hoping to find a 9T 8mm pinion in it. I also popped $8 off to China for an 8T. Probably see that one in a month or so.

Whatever pinion I wind up with it'll be pulling on a 36T scooter sprocket and that should be in the ballpark as compared to those bicycle motors. They have an internal 4.1 to 1 geared reduction. An 8T yields 4.5 to 1 and the 9 would be an even 4:1.

The bicycle motors are also a standard 10T on the output sprocket most guys run around a 40T rear sprocket. Out back I'm at 12/42 right now but both of those are readily available in a multiplicity of sizes. 8-16 on one and 36-54 on the other.

Something's gonna work.
You do realize that most 3:1 transmissions from a pocketbike will make your bike go backwards requiring you to flip the engine around 180 degrees....Right?

You need a 7:1 reduction pocket dirtbike transmission....They don't reverse drive direction.....



The smallest Ive ever found for T8F is an 11tth sprocket for the coarse splined shaft transmissions...……..

https://www.amazon.com/Transmission-...69762206&psc=1

https://www.amazon.com/Transmission-...T8Q6CZC4TGM2BZ


The 9tth that is available has a much different double back to back D shaft mount used on the electric bikes and the motorized bicycle transmissions dedicated for the cause........



If you ever look closely at the bicycle stuff on bikeberry youll see the sprocket output shafts are twice as long as a pocketbike…….They look similar but they've been modified and some even have a double "D" shaft mount...………..

01-03-2020 04:14 AM
EPR
Re: Pinion and Chain Interference

When the Chinese translate into to English, bad things happen, lol. My last problem was they showed a photo of piston port case, with this long title 49cc and all this different bikes. I ordered the cases and got reed port cases. I said to the seller about what they were doing and they started making excuses. I told them to change the photo and they refused. I told them in America you can not show a Ford and send a Chevy. The last set of Piston Port case I bought there were no case half pins, had to steal then from a broken engine part, have had bad coils delivered. Another thing, Parts is Parts, not all parts are they same, have to be careful who you buy from, if it looks to go to be true, it probably is.
01-02-2020 08:13 PM
pntrbl
Re: Pinion and Chain Interference

Something's gonna work! Right now I got a 3:1 box scheduled to be here Monday and I'm hoping to find a 9T 8mm pinion in it. I also popped $8 off to China for an 8T. Probably see that one in a month or so.

Whatever pinion I wind up with it'll be pulling on a 36T scooter sprocket and that should be in the ballpark as compared to those bicycle motors. They have an internal 4.1 to 1 geared reduction. An 8T yields 4.5 to 1 and the 9 would be an even 4:1.

The bicycle motors are also a standard 10T on the output sprocket most guys run around a 40T rear sprocket. Out back I'm at 12/42 right now but both of those are readily available in a multiplicity of sizes. 8-16 on one and 36-54 on the other.

Something's gonna work.
01-02-2020 01:50 PM
EPR
Re: Pinion and Chain Interference

Both them eBay adds are wrong, they are #25 6, 7 & 8 tooth housing and pinions. They are mis-labeled, they say 7 tooth 05T but always show a 6 tooth #25. I have searched World Wide and can't find a 7 tooth 8mm pinion.
Looks like your chain is too tight, when the chain is moving forward, it may not touch, cause the top force will make the chain loose on the bottom side of the pinion and to the rear sprocket.
01-02-2020 12:25 PM
CAM2
Re: Pinion and Chain Interference

Quote:
Originally Posted by pntrbl View Post
I've been digging and EPR's right on the 3:1 gearbox. According to a Bike Berry video on the inside they're 9T and 27T. The 11T reference is a common output sprocket for 05T chain.
The T8F pinions come 6tth -8tth and these are facts also .....Its always been......The decline has made things awefully hard as sellers aren't as diverse anymore...Its like trying to find 100% Original non-repop 57 Chevy Stainless trim panels or Hideaway lights for a Camaro ......

Some vehicles with the smaller 4" rim wheels have problems getting down in the ratios therefore a 3:1 reduction box was needed...

My Extreme XG499 scooter has a 3:1 reduction box because it has the smaller wheels aswell as a T8F chainset……...

In the bike building game it helps with the much needed gear reduction aswell as aligns to the bikes drive [pedal]sprocket a lot better on some builds too.

Most bike guys use the forward pedal crank as keeping the proper drive ratio then adjust the gearing of the engine to deliver a nice smooth powerful takeoff and yield nice n high topend speeds rather than altering the rear rim to affix a larger sprocket..

Just think....If a normal humans legs have only so much power and can pedal only so many revolutions [50-100rpm's]and yield a short burst max topspeed on a bicycle at around 20-25mph average....

If an engine is reduced down with a 3:1 reduction box from the 8400 rpm's the engine produces now gives you actually 2800 output shaft rpm's of all around useable power that's still way more revs than a humans legs can produce in a single minute which will yield ridiculous topend speeds depending on the size of the pinion dictates torque aswell as topend rpm's...

Just adding an 18-24v 900 max rpm cordless drill motor set to torque setting to the pedal sprocket of one of my coaster brake bikes yielded a topspeed of 33mph the way its geared from the drill to pedal sprocket to save the drill from burning up which cuts the revs down to around 250 rpm's of useable overall pedal power ......

What do you have the gear ratio set at on your build right now...……?
01-02-2020 11:18 AM
CAM2
Re: Pinion and Chain Interference

Quote:
Originally Posted by pntrbl View Post
Got that chain on E-Bay for $9. Shouldn't be too surprised.

I've searched several times for a larger pinion but finding them with the extra bit of shaft for the outboard bearing has been problematic. I also need 8mm chain and most of 'em seem to be for #25. This fruitless search has reached the point to where I'm thinking of ways to add that extra bit of shaft myself.

Have you guys got any good sources?
I always have sources,resources and ways around things also to mention know how to find things fast..

This is what you want ….With the right keywords they can be found pretty easily....

https://www.ebay.com/itm/6-7-8-Tooth...pA5mgQS3SrYHUA





Back in the day 6,7 and 8 T8F w/ 3rd bearing support pinions were everywhere and #25's were harder to find....LOL

Even EPR's MT-A4 watercooled replica came with a 6tth T8F chainset…..

If you select right you can still get the 7tth and 8tth T8F chainset pinion w 3rd bearing support shaft..
[You better hurry though..LOL\]

If the guy sold you a #25 chainset pinion in that housing the chain wouldn't even fit on the pinion and wouldn't spin without the chain riding high on the links..

Like you stated its a cheap chain...The pinion is too....Do a runtout / tooth spacing check on the pinion then spec the chain do the math and scratch your head........LOL

https://www.ebay.com/itm/7T-T8F-Clut...sAAOxyzGlQ4Ohu


You can buy this one too...it doesn't have the pinion shaft but will work...

https://www.ebay.com/itm/47cc-Clutch...4AAOSwEeFVKEtX

You put the guts right in your housing and put the bearing cap back on and no-ones the wiser….LOL
01-02-2020 10:59 AM
pntrbl
Re: Pinion and Chain Interference

I've been digging and EPR's right on the 3:1 gearbox. According to a Bike Berry video on the inside they're 9T and 27T. The 11T reference is a common output sprocket for 05T chain.
01-02-2020 12:02 AM
pntrbl
Re: Pinion and Chain Interference

It was advertised as a 6 tooth 8mm clutch housing when I bought it for the extra bearing, and I have another housing with a visibly thinner 6 tooth pinion. Gotta be a #25 on that one.


And if they only make 6 teeth in an 8mm 05T pinion that would explain why I can't find one. I've looked ... I shoulda just asked here first.


Now that you've mentioned it I've realized I had one of the larger 8mm pinions in a 3:1 gearbox at one point. It died and went into the trash over a rusted clutch drum that was frozen in place. But I don't remember it having 11 teeth tho. What I do remember is that gearbox was actually 3.25:1. Or was it 3.24? I dunno. But I'm learning!


Do you suppose I could run a #25 pinion in a 8mm chain? I don't see why not. And I really could add that extra bit of shaft for the outboard bearing. I've got an 1/8" reamer that's half a thou undersized just for press fitting an 1/8" dowel. I'd press the dowel into the pinion and then press a piece over the dowel. That'd work. Actually it'd be better! At .007 clearance to the bearing the original shaft's a joke. I can do better than that.


But all opinions are welcome. Feel free.
01-01-2020 09:58 PM
EPR
Re: Pinion and Chain Interference

Are you sure that's an 8mm pinion?? That chain is usually on an 11 or greater trans sprocket to a 33 tooth rear one. They only make a 6 tooth in 8mm 05T pinion. If you are not using a third bearing cap cut the shaft off and grind it flush. You can still put the cover back, when the chain breaks or comes off the pinion it will protect you. I had one explode off in little pieces mostly just the mounting bolts left when the chain jumped.
01-01-2020 08:15 PM
pntrbl
Re: Pinion and Chain Interference

Got that chain on E-Bay for $9. Shouldn't be too surprised.

I've searched several times for a larger pinion but finding them with the extra bit of shaft for the outboard bearing has been problematic. I also need 8mm chain and most of 'em seem to be for #25. This fruitless search has reached the point to where I'm thinking of ways to add that extra bit of shaft myself.

Have you guys got any good sources?
01-01-2020 05:40 PM
CAM2
Re: Pinion and Chain Interference

Quote:
Originally Posted by pntrbl View Post
Lookit this!


The endplates of the chain are hittin' the shaft. I smeared some ink on it with a felt pen and the little shiny marks appear. Cheap chain? Seems like those endplates should have some relief cuts in them.

BTW, that bottom tube is straight. Something to do with the camera.
One thing I see is the pinion is cut a lil too deep...Modify the 6tth by grinding in a small relief on both sides or get a new 7tth pinion and the problem will be fixed...…

On my homemade r/c buggy I took a 6tth pinion and modified it a lil with a dremel and small stone grinder attachment ends to get the TF-8mm chain to work flawlessly work with a #35 chain and sprocket.....

01-01-2020 05:22 PM
MrKitty should be like this
01-01-2020 04:47 PM
pntrbl
Pinion and Chain Interference

Lookit this!


The endplates of the chain are hittin' the shaft. I smeared some ink on it with a felt pen and the little shiny marks appear. Cheap chain? Seems like those endplates should have some relief cuts in them.

BTW, that bottom tube is straight. Something to do with the camera.

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