Looking for some folks who did the torsion bar mod on CB450 CL450 Cb500T

[joevirus563]

Hi guys,

I'M calling all the guys that did the torsion bar mod (Grind one tooth off) to get them tighter.

I'm looking for a long term reliability test and cam wear test.

Let me hear ya!

 

[joevirus563]

Re: Re: Looking for some folks who did the torsion bar mod on CB450 CL450 Cb500T

Hi guys,

I'M calling all the guys that did the torsion bar mod (Grind one tooth off) to get them tighter.

I'm looking for a long term reliability test and cam wear test.

Let me hear ya!

No one?

 

[kopcicle]

According to Jim Kibblewhite the service life of the torsion spring was drastically limited . This was a race only modification where durability was not a priority . Far better to lighten the valve train via Hansen Valves or titanium via 707 racing once Ryan gets back on his feet . Additionally the Ti valves will need bronze or beryllium copper seats so tuck that away where you won't loose it . I've not heard of anyone even attempting to reproduce the original torsion bar in decades .

~kop

 

[joevirus563]

Re: Re: Looking for some folks who did the torsion bar mod on CB450 CL450 Cb500T

According to Jim Kibblewhite the service life of the torsion spring was drastically limited . This was a race only modification where durability was not a priority . Far better to lighten the valve train via Hansen Valves or titanium via 707 racing once Ryan gets back on his feet . Additionally the Ti valves will need bronze or beryllium copper seats so tuck that away where you won't loose it . I've not heard of anyone even attempting to reproduce the original torsion bar in decades .

~kop

I hear ya.

But I've found a few post around 6 here on dotheton taking about that mod and people who did it.

I'm trying to have there opinion.

Also on sohc Honda forum Hondaman still talk about that mod.

 

[frogman]

That mod is supposed to help with getting the engine rev's up above 10k consistently without having them bounce or float. That's it, higher rpms not massive amounts of power. If you are not going to take it up there, then I will concur with kop, more pressure on the valves means more pressure/power required to open them means accelerated wear on the parts that open them.

Now I've read those pages too where Hondaman and others have recommended it. Maybe your questions are better asked to him, I know he still answers emails, he did it back in the day when these engines were new.

 

[joevirus563]

Re: Re: Looking for some folks who did the torsion bar mod on CB450 CL450 Cb500T

That mod is supposed to help with getting the engine rev's up above 10k consistently without having them bounce or float. That's it, higher rpms not massive amounts of power. If you are not going to take it up there, then I will concur with kop, more pressure on the valves means more pressure/power required to open them means accelerated wear on the parts that open them.

Now I've read those pages too where Hondaman and others have recommended it. Maybe your questions are better asked to him, I know he still answers emails, he did it back in the day when these engines were new.

Thanks.

The thing is that I have a set of a little weak one the stock setup torsion bar. If I push real hard on the intake one I can slightly open the... I'm thinking of sound the mod just to use them some more.

 

[frogman]

When I put my engine together I could barely open the valves as well. It runs right up to 9500 rpm just fine.
Matter of fact I think that limit is the ignition failing to keep up not the valves floating.

 

[joevirus563]

Re: Re: Looking for some folks who did the torsion bar mod on CB450 CL450 Cb500T

When I put my engine together I could barely open the valves as well. It runs right up to 9500 rpm just fine.
Matter of fact I think that limit is the ignition failing to keep up not the valves floating.

OK so I'm not the only one... But still that scares me...

I have dyna electronic ignition so that won't be the weak point.

 

[kopcicle]

Re: Re: Looking for some folks who did the torsion bar mod on CB450 CL450 Cb500T

OK so I'm not the only one... But still that scares me...

I have dyna electronic ignition so that won't be the weak point.

Dyna ? pffft , one day one side will quit for no reason and you'll have no recourse .
I just have no faith in the Dyna at all .

~kop

 

[Flugtechnik]

If you are worried, find the install torque and measure it.

 

[joevirus563]

Re: Re: Looking for some folks who did the torsion bar mod on CB450 CL450 Cb500T

If you are worried, find the install torque and measure it.

OK and how would you measure it? I'm all ear.

 

[Flugtechnik]

I can't find a picture of it, but to install my torsion bars, I took a cheap socket that was slightly bigger than the taller part of the torsion bar fitting shown below, and cut a notch in it so the arm of the fitting fit in the notch. You then just use a torque wrench to turn the bar until it slips onto the dowel pin.

Like I said, I don't remember the torque and I have lost the spec sheet my mechanic gave me.