Aero aids in Classic Modified open

[gschuld]

So perhaps a little clarification is in order, or at least requested.

I?m particularly interested in the area in front of the forks/yoke assembly.  The rules state no aerodynamic aids(other than strict fender and seat/tail limits).  But at some point that needs to be a judgement call.  And device that helps more cleanly split the air at the front of the bike in front of the rider?s upper body/helmet is an aerodynamic aid.  Maybe not a huge benefit, but it?s there.

Clearly gauges(etc) (maybe ram air snorkel) mounted fwd of the trees/yoke is a logistical necessity for some.  That can be done cleanly or in a very ?dirty? manor.

Take the photo below(credit to Scootershoots.com👍)

This bike uses a billet shaped headlight is clearly not useful as a headlight as it is turned around bullet fwd.  I assume the backside holds a few gauges/etc.

It would be helpful to know roughly where the line is drawn in this area.  Any racer wants to consider potential advantages but not risk being disqualified or have to do some sort of emergency reconfiguring to pass tech.

Is there some guidance available on this?

Thanks in advance

George

[wobblywalrus]

Some caution is needed when looking at photos.  There is a clause in the AMA rules that allows a "time only" run for a bike that meets safety requirements for a class and is not in full compliance with the build guidelines.

[gschuld]

Good point.  There are several examples to choose from however.

George

[wobblywalrus]

That is a Modified Pushrod Gasoline bike.  What rule clause does it not meet?

[donpearsall]

In the first photo, the headlight turned around should have been disqualified IF it was running for a record. I don't think there is any exception for turning a stock headlight into streamlining.

But the class shows 500cc blown fuel. I want to see the turbo or supercharger setup up on a carbureted 2 stroke. Hmmm. I am skeptical.

Don

[gschuld]

OK, so the first one seemed more obvious to me.  A bullet shaped headlight bucket turned around.  Clearly not a headlight being a headlight.

The second one is more of a mystery.  The small headlight and bucket offers some advantage over not having one.  It is plausibly or actually factory equipment.

So for Modified classic open class, I?m OK running a stock or near stock(size wise) headlight and mount ears as long as the lens is taped over for safety and it is facing the right direction?

Is that only OK if the bike is registered and street legal(otherwise, no plausible need for a headlight), or does that matter(I assume not)?

And something like this below with a long ram air intake duct routed way fwd for clean air, that?s OK in an non fairing class as well?  If a few gauges were mounted to the top of that ram air duct fwd of the trees (ideal viewing position), that?s OK?  Covered by a full fairing for MPS, that would be very workable.

But would it be an issue in MCG?

I realize I?m splitting hairs here... but that as racing right.😎

George

[gschuld]

Hard to imagine this one is a street bike🤔, nor is the headlight a factory part being the chassis appears to be from a vintage lay down dragbike (it?s awesome BTW👍). That oversized headlight functionally is clearly an add on for aero benefit.  So I assume that?s OK then in open class?

George

[wobblywalrus]

My comments are based on the 2021 AMA regs.  There are no clauses specifically prohibiting that in modified class.

A question of mine...  A bike with M on the number plate is modified.  MPS on the plate means modified partial streamliner.  What letters on the plate designate an open modified bike? 

[gschuld]

In the AMA regs:

M is modified (no streamlining other than strict front fender and seat/tail)
MPS is modified partial streamlining 

Partial streamlining allows extensive fairings, making these questions moot. 

I am particularly asking in regards to the modified (non streamlining) class.

George

[Chris V]

when my wife was riding in the P-CG and the headlight was slightly tilted upward scutinering wanted it pointing straight forward in what would be a normal riding position.

[wobblywalrus]

According to these rules as written, there are no restrictions on streamlining in modified class. 

[donpearsall]

In the first photo with the turned around headlight - I don't think this bike ever passed scrutineering. No chainguard. That is required in all classes.

Don

[gschuld]

Chris,

Makes sense to me👍

WW,

Modified CG ?open class? derails are below.  Strict limits on front and rear fenders/seat are supposed to be it aero wise.  No other fairings of aerodynamic aids allowed.

Modified partial streamlining opens up to all sorts of full fairing work.

Don,

Nice catch on that one. I hadn?t looked that closely and assumed it was inspected as it was at the BMST event from the ScooterShoots.com 2019 collection.  My bad.  Not sure how he wa allowed to run even the run what you brung class.

[Stainless1]

Come on guys, I see a chain guard and scrutineering stickers... maybe that is actually a really large tach....  have not seen a limit on gauge sizes...  But it looks illegal for open... but that only counts if he takes it to impound.  Maybe he was checking if it went faster than the PS record with the headlight turned around...

[gschuld]

So what?s the deal with this one.... it?s obviously in an altered classes based on the rigid chassis, but they base the same on streamlining rules in ?open? class as in Modified as I recall.