poor quality repop silencers

[Bill Thomas]

OK, My !, Idea was not so new !, Just to me, It's all been done before.
The lady says She thinks She has a "C" Down pipe away at the platers,
But She has Lots of "A" Comet ones, Now all I need is an "A" Comet !,
Ron could not give them away, Back in the day, If only I knew !.
Cheers Bill.

 

[macvette]

well i got the Spares Co. silencer in the mail today. Started the bike with the Cambells, then swapped for the Spares Co. one to have the difference fresh in my mind. HUGE difference in sound. Definitely a lot louder (which i like) and the crispness is there as well. Sounds impressive! Unfortunately i ran out of spare time before i could do some test and tuning but so far i am very impressed! will report back!

This is my bike with a spares co spiral baffle silencer. I fitted it because the previous silencer was restricting the bikes acceleration in top at 80. with this silencer, the bike pulls strongly in top from 70. to hear the true sound, you need to listen on a PC with decent speakers or through a smart TV.
Mac

 

[Bikerjoan]

This is my bike with a spares co spiral baffle silencer. I fitted it because the previous silencer was restricting the bikes acceleration in top at 80. with this silencer, the bike pulls strongly in top from 70. to hear the true sound, you need to listen on a PC with decent speakers or through a smart TV.
Mac

Sounds really good to me Mac !

 

[Martyn Goodwin]

This is my bike with a spares co spiral baffle silencer. I fitted it because the previous silencer was restricting the bikes acceleration in top at 80. with this silencer, the bike pulls strongly in top from 70. to hear the true sound, you need to listen on a PC with decent speakers or through a smart TV.
Mac

Is that big end knock? And a whisker of piston slap?

LOL

 

[macvette]

Is that big end knock? And a whisker of piston slap?

LOL

Does sound like that on smartphone or tablet. The exhaust has a really solid beat so no its not.

 

[macvette]

I think we're in danger of tunnel vision here. The silencer won't suddenly give 6 bhp more than standard, we're not going to boost a standard Rap to 51 bhp. I suspect the new VOCSC silencer will give more or less the claimed 45 bhp, and less well designed silencers will give less power. Don't forget, the power probably comes from less back pressure, that will make it necessary to rejet the carbs to take advantage, and to make sure you don't run too weak.

Jim, I think you're reaching the limit of good acceleration at 80 mph on a Rap if you change up there. Not only is the acceleration starting to tail off, but you drop the engine speed which reduces the power available, if I want good acceleration I stay in third till well into three figures.

http://www.vincent-hrd.co.uk/story.html

This piece of advice intrigued me so I dug out the riders handbook because I remembered it quotes max safe speeds in the gears. For a Rapide with standard 46 rear sprocket at 100mph in top gear, it quotes 4600 rpm. Max safe speed in 3rd is quoted as 96 mph. 100mph in 3rd with standard 46t rear equates to approx 7500 rpm so "well into 3 figures in 3rd" seems excessive for a standard Rapide. I've not seen a hp/ torque curve for a Vincent but I'm pretty sure that at those revs, peak torque will have come and gone. Torque is what give acceleration so hanging on excessively to intermediate gears is counter productive.
Having changed to Spares co silencer and warmed her up, I gritted my teeth and hung onto 3rd a couple of times. It wasn't scientific but to me acceleration was falling off around 80 to 85 mph and I felt I was abusing the motor. I haven't done it since so now If I'm in a hurry, I change up to top at 70 when acceleration acceleration in top is strong. If pottering I change up at 60.

 

[Bill Thomas]

I think there is something wrong with your numbers Mac' ?.
From the top of my head, I am thinking 90 mph in 2nd is 6000 revs.
110 is 6000 in third.
I once did 124 mph in 3rd, Timed, On an airfield, On my road Bike Special. I know it was silly, But I was having a bad day, And it only did 124 in top. Cheers Bill.

 

[macvette]

I think there is something wrong with your numbers Mac' ?.
From the top of my head, I am thinking 90 mph in 2nd is 6000 revs.
110 is 6000 in third.
I once did 124 mph in 3rd, Timed, On an airfield, On my road Bike Special. I know it was silly, But I was having a bad day, And it only did 124 in top. Cheers Bill.

You're quite right, I've read the gear ratios "backwards" in the riders hand book. Back to the drawing board , I'm embarrassed , sorry

 

[Bill Thomas]

No Problems Mac'. I am no good with these things, But 10 years of Sprinting, It's in my head.
In the end I was using all 4 gears on the standing 1/4 mile and a 56 rear sprocket, Going over the line at 110 mph.
Just seeing your 7500 at 100 in 3rd, It woke me up and I thought , What the hell was I doing at 124 !!!!.
All Good Fun. Bill.

 

[macvette]

No Problems Mac'. I am no good with these things, But 10 years of Sprinting, It's in my head.
In the end I was using all 4 gears on the standing 1/4 mile and a 56 rear sprocket, Going over the line at 110 mph.
Just seeing your 7500 at 100 in 3rd, It woke me up and I thought , What the hell was I doing at 124 !!!!.
All Good Fun. Bill.

Put my dunces cap on redid the sums correctly. Max safe speed for Rap in handbook is 80 this equates to just over 5900revs. For 3rd safe max is 96 mph equates to just over 5200rpm dont know why its it's different. If I use same safe revs for 3rd as for second, this would give around 108 mph in 3rd.
I'm going to stick with my everyday change ups