joshrandall07
New Member
Hey i have heard of a torsion bar mod where you grind a tooth off to make the bar stronger for less valve floating? Anybody got more info on this. Anybody got pictures of doing it?
Torsion Bar Mod
- Thread starter joshrandall07
- Start date
nrcb125
Been Around the Block
That doesn't sound like it would do anything... The bar's strength is intrinsic to the material properties of the metal. Maybe finding torsion bars which are stiffer (if that's even possible?), or making sure the ones you have are within spec would help.
Well written article about the torsion bar setup: http://www.chinonthetank.com/2012/12/how-cb450-torsion-bars-work/
Well written article about the torsion bar setup: http://www.chinonthetank.com/2012/12/how-cb450-torsion-bars-work/
Flugtechnik
My bike is not transportation, it is a respite
I've heard of it. Never seen it done. It doesn't make it stronger, it makes it stiffer because you are preloading it more.
I imagine you are talking about a CB450/CB500t since those are the only ones I know with torsion bar springs.
The theory is that with a stiffened spring, you won't get as much valve float at high rpm. This would only be valueable in racing. If you are constantly near redline riding on the street, then you are riding it wrong. If you are racing, feel free to play with your engine as much as you want, though a conversion to coil springs would probably be a better alternative.
http://www.m3racing.com/products/parts.html
I have never seen or heard of new torsion bar springs or TBs in other stiffnesses. If your springs have aged and are now out of spec just buy some used ones.
If you are doing this for the street, realize that increasing the stiffness of your springs will increase the wear on your cam followers and cams, both of which are harder to find than the springs and already have some wear issues.
I imagine you have already found it, but hondatwins.net is a great place for technical info on the 450/500Ts.
I imagine you are talking about a CB450/CB500t since those are the only ones I know with torsion bar springs.
The theory is that with a stiffened spring, you won't get as much valve float at high rpm. This would only be valueable in racing. If you are constantly near redline riding on the street, then you are riding it wrong. If you are racing, feel free to play with your engine as much as you want, though a conversion to coil springs would probably be a better alternative.
http://www.m3racing.com/products/parts.html
I have never seen or heard of new torsion bar springs or TBs in other stiffnesses. If your springs have aged and are now out of spec just buy some used ones.
If you are doing this for the street, realize that increasing the stiffness of your springs will increase the wear on your cam followers and cams, both of which are harder to find than the springs and already have some wear issues.
I imagine you have already found it, but hondatwins.net is a great place for technical info on the 450/500Ts.
mydlyfkryzis
当有疑问时踢你的敌人在生殖器上，你可以道歉后
Lighter Valves would also help. Maybe some nice Titanium ones?
joshrandall07
New Member
Yes for the 450 twin. Forget not everybody here rides the same bike. Good point Flug, just really curious about it more than anything. I have read about it a couple of times they grind a tooth off of one of the shafts allowing you to twist the inner shaft more putting more pressure on the valve, like installing a heaver valve spring. Noted to all about not needed for the street but would still like to see how it is done.
Flugtechnik
My bike is not transportation, it is a respite
It should be fairly simple. The splines on the torsion bars have keys (a tooth removed on the male side and a tooth filled in on the female side) so that they can only be aligned in one position. All you have to do is grind off one of the teeth next to the key on the male side. The trick will be figuring out which side to grind it off of. I don't know. Depends on where you do it, and probably which side of the engine it is on.
There are 3 places you could do this, at either end of the smaller inner torsion bar, or on the outer housing where the lifter slides on (outer tube).
It looks like it would be easier to do it on the small bar, but that is the part that is stressed the most and most prone to failure. doing it on the outer tube makes more sense, but it will be harder to grind the tooth off.
There are 3 places you could do this, at either end of the smaller inner torsion bar, or on the outer housing where the lifter slides on (outer tube).
It looks like it would be easier to do it on the small bar, but that is the part that is stressed the most and most prone to failure. doing it on the outer tube makes more sense, but it will be harder to grind the tooth off.
teddpage
Over 1,000 Posts
For 475, you could buy the Valve Spring conversion kit from M3racing...
http://www.m3racing.com/products/parts.html#CB450/500
I realize this isn't the cheapest route, and I would like to see if you plan on modding the torsion bar. It sounds like a neat project! I haven't had issues with valve float on my CB450...but then again, im not racing it.
I do however know a fella who races a CB450 sidecar, bonestock motor aside from exhaust and re-jetting the stock carbs...the bike is SUPER fast!
http://www.m3racing.com/products/parts.html#CB450/500
I realize this isn't the cheapest route, and I would like to see if you plan on modding the torsion bar. It sounds like a neat project! I haven't had issues with valve float on my CB450...but then again, im not racing it.
I do however know a fella who races a CB450 sidecar, bonestock motor aside from exhaust and re-jetting the stock carbs...the bike is SUPER fast!
mydlyfkryzis
当有疑问时踢你的敌人在生殖器上，你可以道歉后
The real question is, why are you having issues with valve float....If you are running in the valve float area, you are pushing the engine too hard....
Unless you are racing, and don't mind crashing the engine occasionally, be gentle on 40+ year old engines...
If you are riding it regularly, then keep it within normal limits and it will last a long time....
If you are looking for all out performance, you are using the wrong motorcycle....
Unless you are racing, and don't mind crashing the engine occasionally, be gentle on 40+ year old engines...
If you are riding it regularly, then keep it within normal limits and it will last a long time....
If you are looking for all out performance, you are using the wrong motorcycle....
