Topic: I need a cam-grind - not sohc

[Old Scrambler]

I am building a Triumph T20 Cub motor to try an assault on the World Land Speed Record at the Bonneville Salt Flats.......My class would be MP-G (Modified Pushrod - Gas). I am building a round-barrel motor with a modified head with BIG valves and extensive porting and an adaptor for a Japanese carb. I found the head on ebay a while back and it got me thinking that it would really make a little 200cc Cub perform.

I have a late-model ('65-67) standard camshaft and followers..........I would like to have it built-up and ground for TORQUE more than high-end HP. I am mating it to a .40" overbore and hope to build compression to 10.5 or more with a roller bearing big-end. The current record is 79.334 MPH.  I have looked at the Megacycle web-page and the closest cam they offer is for a BSA C15. Any suggestions???

[MRieck]

I am building a Triumph T20 Cub motor to try an assault on the World Land Speed Record at the Bonneville Salt Flats.......My class would be MP-G (Modified Pushrod - Gas). I am building a round-barrel motor with a modified head with BIG valves and extensive porting and an adaptor for a Japanese carb. I found the head on ebay a while back and it got me thinking that it would really make a little 200cc Cub perform.

I have a late-model ('65-67) standard camshaft and followers..........I would like to have it built-up and ground for TORQUE more than high-end HP. I am mating it to a .40" overbore and hope to build compression to 10.5 or more with a roller bearing big-end. The current record is 79.334 MPH.  I have looked at the Megacycle web-page and the closest cam they offer is for a BSA C15. Any suggestions???

Interesting. Torque to get it rolling ...big valves will not need the duration. I'll look at those Megacycle grinds. Opposite think for land stuff but small displacement engines/big valves....

[BLUE71TURBO]

 Call WEBCAM.  They are great people !      

                             http://www.webcamshafts.com/

[lordmoonpie]

You could always try Phil Joy at Joy Engineering on this side of the pond? He grinds anything you want and is a camshaft wizard. He's just completed the base circle regrind on my CBR250RR cams - the allegedly untunable ones....find him on google ;-

[Old Scrambler]

Thanks guys for the suggestions..........Right now my chamber is square at 2.52 x 2.52". The intake valve is 1.25" and the exhaust is 1.125" which is the same as the inside diameter of the port and exhaust spigot. I am thinking of sleeving the header pipe for a few inches to increase the scavenge flow. The intake port has been welded and re-angled by about 15-degrees to get a more direct flow to the valve.  Port diameter is 1.125" (29mm) and the surface is brushed like a MR job.  I plan to mount a 28mm rubber tube of about 5" in net length between the extended intake and the likely 28mm carb. The Bonneville salt flats requrie more air volume so I will have a 29mm and a 30mm carb for spares.   

[Gearheadgreg]

American custom cam, Covina Ca, just sent a Valkyrie cam to be reground, this week, http://www.americancustomcam.com/ pricing was reasonable, give them a call the fella was more than helpful and professional. this is what it is going in. here is a friend from the Valk club at Bonneville http://www.timskelton.com/valkyrie/gen_interest/bonnevalk.htm

[Old Scrambler]

Gearhead.........thanks for the tip.......nice link

Now if we could get a separate class for SOHC bikes we might be competitive with our high-tech 750s!

[MRieck]

American custom cam, Covina Ca, just sent a Valkyrie cam to be reground, this week, http://www.americancustomcam.com/ pricing was reasonable, give them a call the fella was more than helpful and professional. this is what it is going in. here is a friend from the Valk club at Bonneville http://www.timskelton.com/valkyrie/gen_interest/bonnevalk.htm

Thanks...I just bookmarked it.

[Gearheadgreg]

Gearhead.........thanks for the tip.......nice link

Now if we could get a separate class for SOHC bikes we might be competitive with our high-tech 750s!

no problem, keep us posted i dig this kind of stuff. I use to use Clay Smith cams also, in So Cal, this guy seems more geared for motorcycles.

[754]

Denis there is a guy on the VRRA site, making fairings for Triumph singles.. dont know if it what you need.
 Has one less screen right now for 135, think he will make some more..

[Old Scrambler]

Thanks Frank........I'll take a look.  Right now I am planning on the MP-G class and not looking at streamlining........Yet!  When the motor is running for more than a few minutes I'll see what I have.  Lots of info gleaned from this site going into the build.........lighter gears & cam........single-row primary to save internal power loss.........building for torque......to turn 21" wheels