Changing the Rear Sprocket (SR4)
Discussion
Hi All,
Just a couple of quick questions...
When changing the rear sprocket do you need to replace the tab washers used to help hold the sprocket in place ? I assume this is a Yes, but thought I would check.
Secondly...Is there a nack to tightening the chain back up evenly without getting any tight spots. I have tried several times tightening it up and the losening it off and rotating it gradually whilst tightening it but it is still a little uneven. Any tips to help sort this out ?
Cheers,
James
Just a couple of quick questions...
When changing the rear sprocket do you need to replace the tab washers used to help hold the sprocket in place ? I assume this is a Yes, but thought I would check.
Secondly...Is there a nack to tightening the chain back up evenly without getting any tight spots. I have tried several times tightening it up and the losening it off and rotating it gradually whilst tightening it but it is still a little uneven. Any tips to help sort this out ?
Cheers,
James
Hi James
For the sake of a relatively few pence, I'd replace them, but that said if they're still entirely sound, you could re-use them - particularly as a lot I've seen have no lock tabs at all
given their low price, if they had seen what a carrier looks like after a sprocket retaining bolt has come loose (and it is capable of damaging the diff), they'd be fitting lock washers. You can get away 99% of the time without lockwashers, but IMHO, the 1% and the low cost makes that a daft risk to take knowingly.
On tightening up the chain, do it slowly and take your time, constantly checking the face to face alignment of the front and rear sprockets. Nip the carrier and hub bolts reasonably tight, but still not tight enough to prevent the adjusters themselves from pulling the sprocket back; when you've got it adjusted right, then tighten both carrier and hub bolts to FT, particularly the latter.
Use the correct diameter piece of broad broomstick/similar hardwood dowel to lock the holes in the sprocket and the hole in the carrier to tighten the sprocket and hub bolts.
Even with a brand new chain and or sprocket, don't expect completely even slack/tension; chains and sprockets just aren't like that; if you happen to have a perfect tension on a new chain, first hard charge and it won't be that way anymore ever again - 500G does tend to stretch things - for racing a chain is lifed at 10 hours, by far the shortest lifing of any component on the car. Find the tightest spot and get that right; if that leaves other parts of the chain with a daft amount of slack (say anymore than twice the correct tight spot amount), a chain change is overdue. And it goes without saying, a too slack chain is not good, but an overly tight chain can be a disaster; quite capable of wrecking the gearbox.
For the sake of a relatively few pence, I'd replace them, but that said if they're still entirely sound, you could re-use them - particularly as a lot I've seen have no lock tabs at all
given their low price, if they had seen what a carrier looks like after a sprocket retaining bolt has come loose (and it is capable of damaging the diff), they'd be fitting lock washers. You can get away 99% of the time without lockwashers, but IMHO, the 1% and the low cost makes that a daft risk to take knowingly.On tightening up the chain, do it slowly and take your time, constantly checking the face to face alignment of the front and rear sprockets. Nip the carrier and hub bolts reasonably tight, but still not tight enough to prevent the adjusters themselves from pulling the sprocket back; when you've got it adjusted right, then tighten both carrier and hub bolts to FT, particularly the latter.
Use the correct diameter piece of broad broomstick/similar hardwood dowel to lock the holes in the sprocket and the hole in the carrier to tighten the sprocket and hub bolts.
Even with a brand new chain and or sprocket, don't expect completely even slack/tension; chains and sprockets just aren't like that; if you happen to have a perfect tension on a new chain, first hard charge and it won't be that way anymore ever again - 500G does tend to stretch things - for racing a chain is lifed at 10 hours, by far the shortest lifing of any component on the car. Find the tightest spot and get that right; if that leaves other parts of the chain with a daft amount of slack (say anymore than twice the correct tight spot amount), a chain change is overdue. And it goes without saying, a too slack chain is not good, but an overly tight chain can be a disaster; quite capable of wrecking the gearbox.
Edited by splitpin on Tuesday 17th November 22:57
No, but I have seen people trying to adjust the chain with the adjusters even when the hub bolts and carriers are on TFT. Is that what caused the elongation? A problem I have seen (easily overcome) is that the welds on the adjusters are just close enough (i.e. too close) to the hub nuts to stop the bigger spanner / socket seating properly; couple that with a big nut done up really tight and it's a great recipe for some seriously skinned knuckles (and a lot of effing)
Its worth pointing out that the sprockets are often not machined spot on / split exactly down the middle, as such you end up with a slack side & overly tight side.
One of mine was so bad that I got Radical to swap it for a new one, bear in mind that was after just the one use so it still looked like new.
One of mine was so bad that I got Radical to swap it for a new one, bear in mind that was after just the one use so it still looked like new.
You can buy laser alignment tools for karting, approx £60 if memory serves. But no need for anything like that as Darren says, metal rule is perfect.
And to add to others comments - you will struggle to avoid having differences in tightness from my experience, go with the tightest spot for play and then check slackest point isn't too slack. Use judgement on this!
And to add to others comments - you will struggle to avoid having differences in tightness from my experience, go with the tightest spot for play and then check slackest point isn't too slack. Use judgement on this!
jamesrose said:
What is the best way to check the alignment of the faces of the sprockets ?
Can I use something like a spirit level ?
Strangely, the SR4's Genuine Radical Dry Sump Dipstick is absolutely perfect for the job; cranked handle ensures it sits perfectly flat on the rear sprocket face and is easy to hold and level end will tell you all you need to know as to alignment of front sprocket.Can I use something like a spirit level ?
takes a bit longer.. but i found when you had the sprockets perfectly aligned and known (by measure +/or reading sprocket/chain wear) it was best to count the rotations of the retaining bolt head on each side of the diff... mark one face of teh hex bolt head white say white marker/paint and its easy to count the turns each side - means its 100% accurate and you can do a quick alihnment with 12" rule or similar as a sanity check......
From a man who has done this many times and has the scuffed knuckles and tears to match.....
We have reused the fold over tab washers many times with no probs...
Check the chain tension in say 4 places.....
You can eye in the chain alignment by looking directly downwards through the top link and into/onto the bottom link...you are looking for the teeth of the sprocket to sit in the middle of the link....
Unfortunately to get it right you need ALL the adjusting bolts/nuts tight so that the final adjustment is not moved.
On the sprocket there is a chamfered edge that either goes to the outside or inside ( I can't remember ) and I can't get to my car to check.
Check all of the chain and nuts bolts etc after every session.
At the start do not dump the clutch but feed in the power.....I'm running on a 1 year old chain....
david
91
We have reused the fold over tab washers many times with no probs...
Check the chain tension in say 4 places.....
You can eye in the chain alignment by looking directly downwards through the top link and into/onto the bottom link...you are looking for the teeth of the sprocket to sit in the middle of the link....
Unfortunately to get it right you need ALL the adjusting bolts/nuts tight so that the final adjustment is not moved.
On the sprocket there is a chamfered edge that either goes to the outside or inside ( I can't remember ) and I can't get to my car to check.
Check all of the chain and nuts bolts etc after every session.
At the start do not dump the clutch but feed in the power.....I'm running on a 1 year old chain....
david
91
double d racing said:
At the start do not dump the clutch but feed in the power.....I'm running on a 1 year old chain....
david
91
You little devil you.david
91
(Expect to hear from R?) "do you think we come up with that lifing stuff for fun, there you go then, that's what caused that oil feed not to be TFT, vibration from a way beyond it's sell-by date chain".
(Expect to hear from D?) "I know now thanks"
jpivey said:
A friend that runs a PR6 in the UK cup has changed the chain once this year and they do lots of hours he puts it down to a super duper chain lube that he swears by and before you ask i can't remember what make it is.
If (as I suspect) it's from Silkolene, here's a composite from those clever blokes in white coats there >This is a question for the Radical guys. Which is the best chain lube for a Hayabusa/Radical application?
I'd say Pro Chain is technically a superior product. But, Ti(tanium) Chain Gel is superb stuff too and as you have to clean the chain very thoroughly before switching products, if they're using Ti, they may decide to stick as they are.
If it was me though, I would switch. I’d go for the Pro-Chain. It’s a thin film lube that stays on at high speeds when G forces on the chain reach about 500X !
As I was already using Ti, we've stuck with it ........... and confession time, my chain is over two years old and still upto it
; to be fair booting it off the line has been rare but Will did do six full bore standing starts at a Sprint and was 3rd fastest to 64 feet of many cars, some with way more power and use specific. That said, fast as hell LCM in "Black Betty" has a twin chain drive on his, so a chain definitely has it's limits
I was going to lash out and have a new chain in 2011, but I'd better bring that plan forward to 2010.....as for junctions being TFT.....( Trev !!) blame that on "taking things for granted and you think you know it all and practise good practices and something still bites you in the bum".......
there was some good came out of it as Aaron ( Jonathans son was commiteed to spannering for me that day ) as I wasn't going anywhere I was able to release him to work on his Dad's car................mind you in saying that so long as my car was ok ( which it had been ) I would still have sent him to help JW.
Cheers
david
91
there was some good came out of it as Aaron ( Jonathans son was commiteed to spannering for me that day ) as I wasn't going anywhere I was able to release him to work on his Dad's car................mind you in saying that so long as my car was ok ( which it had been ) I would still have sent him to help JW.
Cheers
david
91
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