Another Norton headed for Bonneville this year

Snotzo · May 19, 2019

Joachim, I would question the 85 crankshaft power, and must ask whether this was obtained via a direct crankshaft connection, or estimated/calculated from rolling road dyno figures.
If the former, then the output is very credible, but if the latter I doubt there is anywhere near 85 at the crank

cjandme · May 19, 2019

Ditto, great stuff and thanks for posting/sharing the details. This year is shaping up to be a good one for Norton land speed record attempts/efforts. This certainly has piqued my interest in the fun ya'll are gonna have Cj

Joachim · May 19, 2019

Snotzo said:
Joachim, I would question the 85 crankshaft power, and must ask whether this was obtained via a direct crankshaft connection, or estimated/calculated from rolling road dyno figures.
If the former, then the output is very credible, but if the latter I doubt there is anywhere near 85 at the crank

Dear Snotzo,
the bike was run on the dyno as you can see in the photos, i.e. engine to rear wheel losses estimated.
Your concerns about the credibility of the power figure are more than fair. All I can say is that all the people involved are very experienced and they belief in the results. There was absolutely no need for anyone to make the results look any better than they are. So in my opinion these results are not less credible than any other results you see on forums like this. Probably no point getting scientific.

jseng1 · May 19, 2019

When Ron Wood achieved 84 HP with his flat track 750 the people at the Norton factory (that was sponsoring him) didn't believe him either. They offered to fly him and his motor to the UK to prove it - and he did just that. I heard this from from Ron Wood personally when we were working on his Rotax single.

Dances with Shrapnel · May 19, 2019

Looks like the cylinder liners were notched to gain exhaust valve clearance. Good stuff!

Ram air should be good for a few tenth of a psig at the carbs.

https://i.stack.imgur.com/433lx.jpg

Something to be cognizant of is the air box/air feed tubes/intake tracts acting as an Helmholtz resonator. Properly designed and tuned it can work for you, otherwise, it will work against you.

Joachim · May 19, 2019

Dances with Shrapnel said:
Looks like the cylinder liners were notched to gain exhaust valve clearance. Good stuff!

Ram air should be good for a few tenth of a psig at the carbs.

https://i.stack.imgur.com/433lx.jpg

Something to be cognizant of is the air box/air feed tubes/intake tracts acting as an Helmholtz resonator. Properly designed and tuned it can work for you, otherwise, it will work against you.

Thank you, will pass on your concerns.

Isn't Ram Air where the air is directly forced into the intake of the carburettors? In this case the pipes go into the air box and the carbs get the air out of the air box. The experts apparently say that the pressure wont increase noticeable within the airbox.

lcrken · May 20, 2019

Thanks for the details. Very interesting build.

Ken

grandpaul · May 21, 2019

I would say some actual run testing of the airbox would be better done BEFORE the trip out to Bonneville! Just seems logical that you'd want to sort that out to the positive, before being disappointed and possibly limited resources to adjust, apart from rough modification or eliminating the ram air altogether...

I know, it's hard to find a long strip, but you can always ask a private airport...

Dances with Shrapnel · May 21, 2019

Ram air is not the issue or problem as long as the float bowls see the air box (dynamic “rammed” air) induced pressure. The resonance of the air box/intake tract/ducting (Helmholtz) system is the question. You can test that on a dyno independent of the ram air effect.

Son of Siredward · May 31, 2019

Tom Mellor runs a similar air induction system into a large air box on both his LSR bikes and has both the 750cc and 1000cc records in M-PG and MPS-PG BST AMA events. Claims to run sea level jetting at Bonneville with the air induction air box.

acotrel · Jun 3, 2019

I don't know how you guys can do that. I don't even like big road race circuits. At least with small circuits - if the crank lets go, you can get off relatively safely.
Take care !

jseng1 · Jun 4, 2019

Here's the happy bunch of culprits with their project.

Another Norton headed for Bonneville this year

Somehow this photo overwrote the original photo I posted at the top of this thread.

Joachim · Jun 5, 2019

To everyone who doesn't believe in the 85HP, here you can hear every single horse

jseng1 · Jun 6, 2019

85HP is an exceptional accomplishment for a 750. Very few tuners have managed that much power.

Mark · Aug 31, 2019

Joachim said:
A bit of background around Rainer's racer....
The exhaust had a massive influence on the power output. They experimented with the length of the reverso cone of the mufflers. At some stage a change increased the max power by about 10HP!

You guys picked up 10hp by just messing with the exhaust. That is pretty impressive, I would like to hear more about what was done to accomplish that.

SteveA · Aug 31, 2019

Mark said:
You guys picked up 10hp by just messing with the exhaust. That is pretty impressive, I would like to hear more about what was done to accomplish that.

And you ended up with something which looks dimensionally very similar to the works Nortons of '74!

Another Norton headed for Bonneville this year

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