For Kel: B Grades bucket build

[cotswold]

erm, ideally 420 goes to 415. 428 has a different pitch as the bushes are a bigger size. Think you have to take it down to 4.3 to give clearance & bevel the edge (numbers only from jaded memory). Ally rear spk is easy to do on mill & file the bevel. Front spkt will need munty cutters so take to an engineer to grind.

Chain Pitch Width Roller Diameter
415 12.70mm 4.88mm 7.75mm
420 12.70mm 6.35mm 7.75mm
428 12.70mm 7.75mm 8.51mm Just found this: pitch is the same but like you say rollers are bigger, does this mean I can just mill the front to the required thickness and run a 415 chain or will the teeth on the front sprocket be too far apart?? My head hurts, it was easier just riding Johns diesel.

[Henk]

Looking at that you should be able to machine down a 420 front sprocket to fit, 428 is a non starter. Is getting the weird rear sprocket machined to turn it into a sprocket carrier for a more standard sprocket an option? If so I think I'd be leaning in that direction.

[cotswold]

Looking at that you should be able to machine down a 420 front sprocket to fit, 428 is a non starter. Is getting the weird rear sprocket machined to turn it into a sprocket carrier for a more standard sprocket an option? If so I think I'd be leaning in that direction.

Oh this looks easier all ready, suzuki do a number bikes with 420 sprockets, plus a few yams and Kwakas, I have a long list if anyone is interested

http://www.ebay.com/itm/Suzuki-Yamah...ht_1731wt_1110

[jasonu]

Looking at that you should be able to machine down a 420 front sprocket to fit, 428 is a non starter. Is getting the weird rear sprocket machined to turn it into a sprocket carrier for a more standard sprocket an option? If so I think I'd be leaning in that direction.

Good thinking that man!
I always thought 428 was the same pitch but wider. Lucky I never actually tried to use it.

[Grumph]

Chain Pitch Width Roller Diameter
415 12.70mm 4.88mm 7.75mm
420 12.70mm 6.35mm 7.75mm
428 12.70mm 7.75mm 8.51mm Just found this: pitch is the same but like you say rollers are bigger, does this mean I can just mill the front to the required thickness and run a 415 chain or will the teeth on the front sprocket be too far apart?? My head hurts, it was easier just riding Johns diesel.

That's not definitive either...OK pitch is the same right through and i think 415/420 uses the same roller diameter,yes, but there's at least two different roller diameters for 428...and i don't know if you've quoted the std Jap size or the British...
This is why it's a pain using 1/2 X 1/4 - 428 in modern terminology, for primary chains on British stuff - use the wrong roller diameter for the sprockets and nothing lasts very long.

For your rear, it may be easier to make one from a blank if it's a weird pitch or width - just go 420.

[cotswold]

That's not definitive either...OK pitch is the same right through and i think 415/420 uses the same roller diameter,yes, but there's at least two different roller diameters for 428...and i don't know if you've quoted the std Jap size or the British...
This is why it's a pain using 1/2 X 1/4 - 428 in modern terminology, for primary chains on British stuff - use the wrong roller diameter for the sprockets and nothing lasts very long.

For your rear, it may be easier to make one from a blank if it's a weird pitch or width - just go 420.

It's the shape of the rear that is the pain as it is splined and dished so will give the machining the front a go 1st

[Pumba]

I am going to do something similar using the tank cover, I was just thinking of modifying the tank I have rather than buying another

Hmmm, yea didn't realise/forgot that the tank was just a cover for another tank.

[Moooools]

why don't you just get a 428 chain and put it over each sprocket to check that the pitch is right?

[Henk]

why don't you just get a 428 chain and put it over each sprocket to check that the pitch is right?

I'm pretty sure that is what he was showing us in post #70

[Henk]

Tim

If you want to try a 420 chain on your rear sprocket for pitch let me know. I'm pretty sure I have one somewhere.

[Moooools]

oh right. Half asleep still.

As you were.

[aircooled]

all my bikes run 415 chain & 428 sprockets ground to 415 pitch, about 4.3mm thick.

never had any chain wear problems yet, ones been running 4yr,s same set up.

[F5 Dave]

I run 420 down to 415. Front spr is where it gets critical as such a tight bend. Power to be lost there.

With the dished sprocket, what a pain, but can you (help me out Grumph) Scotch key(?) it to another sprocket? What I've done on mine is use a larger 50 tooth MX ally sprocket & cut the original down to fit inside the skinny MX one. Then bored 3 holes (that's the key bit) & bolted together with washers. Think of it like a rivited floating disc brake.

It's ye olde method & used on brit stuff from time to time.

You may not have enough diameter room.

[jasonu]

I run 420 down to 415. Front spr is where it gets critical as such a tight bend. Power to be lost there.

With the dished sprocket, what a pain, but can you (help me out Grumph) Scotch key(?) it to another sprocket? What I've done on mine is use a larger 50 tooth MX ally sprocket & cut the original down to fit inside the skinny MX one. Then bored 3 holes (that's the key bit) & bolted together with washers. Think of it like a rivited floating disc brake.

It's ye olde method & used on brit stuff from time to time.

You may not have enough diameter room.

As the Aprilia sprocket is dished and therefore offset I would cut down the original then remove the center from (say) a 50t so when placed on top of the Aprilia center they overlap. Then work out how much more offset you need, make the appropriate spacers then drill and bolt them together. That way you could do the same with other sized rears and use the same Aprilia center part as the mount.

[F5 Dave]

Yeah, even if you recess it into the wheel 2mm & make a step in the original sprocket.

Look at JT website for large skinny sprockets. Mine is KX80 (420 thinned to 415) & have large inner, thus I can match any KX sprocket to my fitting with just 3 semicircles filed or bored in the right place.