Exhaust reversion
- Thread starter charles d cannon jr
- Start date
Thanks Roy and piggywig. That information has probably saved me a lot of heart ache and expense. So what springs are available which will do what we want. That is, reasonable pressures and not binding up at half an inch of lift. To me Terry Prince is one of the good guys who has put a lot of time and his own money into improving the breed but we all make mistakes. I could not agree more about the usefulness of this Forum and Grahams contribution.
Do you mean radial load? Pure axial load seems good.
Unfortunatly I am sworn to secrecy as to the scource of my springs, they "escaped " through the back door, Panic not- go back a few posts, Davidd has given us an excellent link to a spring supplier with a most informative spec sheet.
Terry has supplied RD race springs for years. I bought a set from him in 2004, they are in my Oz Rapide which has done 40,000 miles to date and still pulls to 115 mph on request.
The RD springs are in nearly every bike in the Vancouver section and ther have been no problems as far as I know, in fact they solve the problem found with club springs.
Terry may have also supplied some other springs, but if they are RD you cant do better. RD springs can also be purhased directly.
Glen
The RD springs are in nearly every bike in the Vancouver section and ther have been no problems as far as I know, in fact they solve the problem found with club springs.
Terry may have also supplied some other springs, but if they are RD you cant do better. RD springs can also be purhased directly.
Glen
Terry and his wife Ursila a few years back, spent a few days at the house visiting , lots of time spent in the shop . Terry made the two stroker cranks for the liner and the 1/2 longer muffs. We talked about springs cams and all the go fast stuff, Terry has lots of knowledge and most of the time we are on the same page. Terry when racing the salt always pits near the liner, bringing the racer across the pond is a logistic nightmare. There is always a tool , part, consumable left behind, if we have its his, just about every Vincent guy has visited the liners trailer at one time or another and at times something as simple as a bolt has saved the day, that's the comradry of racing, just simply love it, helps make it all worthwhile .
MAX
MAX
In my opinion this is normal, even with correctly timed cams. It happens on the Flash and the Shadow and was the same on the Comet when it was running. The knowledgeable man who set up both my Flash and Shadow on a dyno explained that there must be some blow back when the inlet valve opens before TDC unless the exhaust is perfectly tuned, which only happens over a limited part of the range. With the Shadow, which runs with air filters, the blowback is contained and continues into the engine. Thus the machine runs very reliably with "weak" 160 main jets. Just a thought.
Glyn Baxter
Glyn Baxter
Many years ago when I used to try to do a bit of racing and sprinting it was clear that correctly timed MkII cams gave about 6 to 9 inches of blow back at low revs. This would slowly reduce as the revs increased until at about 2,000 rpm it became negligable. Over the years while trying to help others, who sometimes did not know what cams they had, it was a very easy check. If there was a lot of blow back below 2,000 rpm then either they had MkIIs or the cams were incorrectly timed. I and many others have used MkIIs for road use but they are not ideal for low speed smooth running. I once spoke to Phil Irving about this and his opinion was that power would be reduced below 4,000 rpm with MkIIs.
Most racing automobile cams have offset keys to advance 0r retard the cam to suit the purpose, sprint or top end. The use of a dyno is a must to determine which set up is best, the seat of the pants tuning very seldom gets it. Just my experience .
Regards MAX
Regards MAX
The best example of the advantage of moving the cam timing to get best power at low and high RPM is the TOYOTO truck which changes the cam timing on the move as needed for best performance.
BEST Max
BEST Max