Bucket bits wanted & services needed

[gav]

Buckets? What you describe is any class of road racing.

My comment has nothing to do with the class of racing you do.....Its about a basic understanding of engineering and making out that you know when you don't offering bad advice at the cost of others.

SHEESH......

You do realise you are in a bucket racing forum don't you??

[RGVforme]

You do realise you are in a bucket racing forum don't you??

Thanks for that

Based on this post and the last I was starting to think it was the 'pluck shit out your bum and offer it up as sound advice' and now the 'state the obvious forum'.

You do realize that bad advice is bad advice no matter what the forum thread is don't you?

Good on both of you for trying to get it though little buddys.

[chrisc]

After a FXR150 to buy if anyone has one for sale. Would be very keen to get it ASAP before the GP at Tokoroa if possible. Located in Auckland but willing to travel.

Also after some second hand racing leathers for someone who would normally be a size medium in other things.

Message me.

[Askor]

Thanks for that

Based on this post and the last I was starting to think it was the 'pluck shit out your bum and offer it up as sound advice' and now the 'state the obvious forum'.

You do realize that bad advice is bad advice no matter what the forum thread is don't you?

Good on both of you for trying to get it though little buddys.

You sound like an armchair engineer - someone who "knows it all" but has never touched a spanner other than to change his own oil.

Whatever happened to kiwi ingenuity? "I don't have a soft enough spring on hand to test something. Modify the original spring? Are you mad?!"

[Autech]

Thanks for that

'pluck shit out your bum and offer it up as sound advice'

It's not like Yow Ling has been racing bikes since I was in nappies or anything, oh wait, he has... Now I wasn't born yesterday so it would be safe to assume he knows just a tiny bit what he is talking about.

To clarify for you, bucket racing is all about low cost, simple solutions to go as fast as fucking possible on a tiny wee bike. If that involves grinding a wee bit off here and there, then everyone in this thread is up for it. I can absolutely guarantee that if someone told the Ducati Motogp team that if they ground a bit off their bike they would be .1 a lap faster, they would do it in a heart beat.

[F5 Dave]

Actually despite the utmost respect for Mike, I don't think I would grind a spring. The local forces and heat involved could cause a fracture point. Further its effectiveness would count only in the area of reduced wire thickness.

[Yow Ling]

Actually despite the utmost respect for Mike, I don't think I would grind a spring. The local forces and heat involved could cause a fracture point. Further its effectiveness would count only in the area of reduced wire thickness.

What if you ground it on a cylindrical grinder?

[F5 Dave]

That would be far more effective. If you could keep it cool it would be better. Getting past my pay grade calculating the resultant reduction of strength. Finding another spring and pushing them together with a tape measure to see which one is softer sounds easier.

But be weary of springs, they store large amounts of energy.

[Ocean1]

Actually despite the utmost respect for Mike, I don't think I would grind a spring. The local forces and heat involved could cause a fracture point. Further its effectiveness would count only in the area of reduced wire thickness.

I've turned spring outside diameters to fine tune them before now. What works is turning up a mandrel from a bit of pipe, maybe 0.1mm larger than the spring ID. You can wind the spring onto the mandrel like nut onto a bolt, it'll stay there during a normal feed, (right to left) because the force from the cut reaction tightens it onto the mandrel, (works for clockwise/RH wound springs, LH springs you need to turn cutting from the chuck out).

Once you've got that lot chucked up you can turn the OD down a little, unwind the spring from the mandrel to measure load rate and wind it back on again as needed.

Now. Since developing that procedure a long time ago I've had occasion to refine it a bit. The last few times I've used a coarse sanding disc on my 5" grinder, taking light cuts to keep the heat to a minimum, (if you can't hold your hand on it you might be in trouble). Grinding/sanding over the best lathe bed had the ghosts of several old timers yelling abuse in my head, but keeping the saddle down the arse end and cleaning up carefully afterwards kept the guilt to a minimum. And it actually works better and faster than turning them.

Spring load rate seems to change roughly in proportion to CSA, taking 2mm off the OD of a rear shock spring makes quite a difference.

Powder coating. Don't. The heat MAY be enough to fuck the temper.

[RGVforme]

Actually despite the utmost respect for Mike, I don't think I would grind a spring. The local forces and heat involved could cause a fracture point. Further its effectiveness would count only in the area of reduced wire thickness.

Now this is engineering......Simply having a go and seeing what happens is just trial and error.

There is stupid learning and then there is smart learning.

[Grumph]

I've turned spring outside diameters to fine tune them before now. What works is turning up a mandrel from a bit of pipe, maybe 0.1mm larger than the spring ID. You can wind the spring onto the mandrel like nut onto a bolt, it'll stay there during a normal feed, (right to left) because the force from the cut reaction tightens it onto the mandrel, (works for clockwise/RH wound springs, LH springs you need to turn cutting from the chuck out).

Once you've got that lot chucked up you can turn the OD down a little, unwind the spring from the mandrel to measure load rate and wind it back on again as needed.

Now. Since developing that procedure a long time ago I've had occasion to refine it a bit. The last few times I've used a coarse sanding disc on my 5" grinder, taking light cuts to keep the heat to a minimum, (if you can't hold your hand on it you might be in trouble). Grinding/sanding over the best lathe bed had the ghosts of several old timers yelling abuse in my head, but keeping the saddle down the arse end and cleaning up carefully afterwards kept the guilt to a minimum. And it actually works better and faster than turning them.

Spring load rate seems to change roughly in proportion to CSA, taking 2mm off the OD of a rear shock spring makes quite a difference.

Powder coating. Don't. The heat MAY be enough to fuck the temper.

Agree completely. An added sophistication which I've seen done is to turn the OD of the spring when on the mandrel, tapered. Rising rate anyone ?

Historically, here in ChCh, there were a couple of places who would wind you up a new spring to your guesstimate. 20% lighter please...yes, sir, next tuesday be OK ? Post quakes, not so much. Yow Ling says Chamberlains. Probably the only jobbing spring maker left prepared to do one offs, here anyway.

[Yow Ling]

Ok back to the engineering, my first suggestion was to grind a flat on one side of the spring, in hindsight this is wrong , we should grind flats on 2 sides of the spring so it deforms more evenly.
I did say to use a surface grinder, this way the cuts are very light and with coolant there will be no heat build up.
Imagine if you uncoiled a spring it would be a straight piece of bar, now those flats we just ground would just reduce the cross sectional area of the bar , so we would have a spring which is more flexible at the skinny end and less flexible at the thick end , just like a fishing rod. As we ground the whole side of the spring we get effectively a whole lot of fishing rods tip to tip and end to end , so long as the strength calculation for the skinny end is within safe limits all will be well. Worst case is we create a spring that is too soft , but hey you can also buy a spring that is too soft and we don't see that as a problem.

[Askor]

Now this is engineering......Simply having a go and seeing what happens is just trial and error.

There is stupid learning and then there is smart learning.

Back to the "state the obvious" forum I see

[chrisc]

After a FXR150 to buy if anyone has one for sale. Would be very keen to get it ASAP before the GP at Tokoroa if possible. Located in Auckland but willing to travel.

Also after some second hand racing leathers for someone who would normally be a size medium in other things.

Message me.

Can you lads stop having this conversation in the "bucket bits wanted & services needed" thread.

Also, someone sell me/my mate a bloody diesel so we can go racing

[Autech]

Now this is engineering......Simply having a go and seeing what happens is just trial and error.

There is stupid learning and then there is smart learning.

It appears you missed out on a few learning opportunities. I feel for you man, I really do.