Electric Plenum Heater Take 2

[slabghost]

Leaving the head ends of the inner pipes unsealed gave the return pulses a big dampener pipe. Fuel charge doesn't flow towards the valves at a steady flow like water from a garden hose it bounces back and forth several times between the intake valve closing and opening.

 

[dan filipi]

The way I see it is.......the smaller pipe inside the bigger pipe reduced the volume inside.
That in turn will 'speed up' the flow.

This has nothing to do with now being a 'venturi' or 'choke' or anything like that, it is simply a reduction in volume inside the runner.

 

[slabghost]

dan filipi » Thu Mar 06, 2014 8:43 am[/url]":2tdqv841]
The way I see it is.......the smaller pipe inside the bigger pipe reduced the volume inside.
That in turn will 'speed up' the flow.

This has nothing to do with now being a 'venturi' or 'choke' or anything like that, it is simply a reduction in volume inside the runner.

You are right. However leaving one end open to the larger pipe created an expansion chamber one way reducing the flow and negating the effects of the reduced runner size.

 

[joedrum]

yes I agree what I have is totally different ... it chambering not reduction .. personally I am finding huge beenies here ... with my work with dust and wood chip collection you have to know how to deal waste at huge level and far distance .....I know most don't agree but chambering keeps the speed and volume up as they asset each other ...with this approach hooch is the most dangerous to me it seems just off idle ...most think its the gearing of hooch yes its low but not that low ... hooch is the first bike ever to yank my hands off the bars ... that raw off idle power big time ..till its proves different I am sticking to what I have ... skirri test ride has pretty much made me decide I am putting a inline venturri back in hooch with the grab bar runners ...might try it without but doubt it

 

[skiri251]

joedrum » Thu Mar 06, 2014 7:07 am[/url]":30cb0jua]
yes I agree what I have is totally different ... it chambering not reduction .. personally I am finding huge beenies here ... with my work with dust and wood chip collection you have to know how to deal waste at huge level and far distance .....I know most don't agree but chambering keeps the speed and volume up as they asset each other ...with this approach hooch is the most dangerous to me it seems just off idle ...most think its the gearing of hooch yes its low but not that low ... hooch is the first bike ever to yank my hands off the bars ... that raw off idle power big time ..till its proves different I am sticking to what I have ... skirri test ride has pretty much made me decide I am putting a inline venturri back in hooch with the grab bar runners ...might try it without but doubt it

You have 1" ID runners and put venturi inside?
This off idle acceleration sounds very attractive to me.
When I heard low end torque increase, I was expecting this. My XT500-like acceleration which puts front wheel in the air.
But then I thought it's impossible with Oldwing. She is so heavy..
But you say it is possible?

 

[joedrum]

well skirri oldwings have all there weight low to the ground even gas ... its very unlikely to get the wheel up very far in this leverage against you ... most likele losse traction ... but yes I am sure hooch can get wheel off the ground with traction ... I don't want to be on it when it happens ... the angry dresser pull the wheel off the ground once two up ... it had the traction then with patty on ... I got hit from behind quite hard ... that was patty LOL
no the runners hooch has had were 1 1/4" and the venturri or choke down in hooch is right at the type 4 plenum it is 1"ID ...pass that it opens to 1 1/4"... with the grab bar runners I am doing now .. it would open back up to 1 1/2" pass type 4 plenum ...and one less joint in the runner to head

 

[skiri251]

Hello Joe.
I don't want Oldwing front wheel in the air either but I meant neck snapping acceleration (to a point, of course) I feel aboard XT500.
Okay, so it's not an easy modification for my current intake.
Well, I look forward to your next build.
I may try mimicking it in the future.

 

[dan filipi]

One reason I've found can explain the increased low end torque is the throttle geometry.
Depending how linkage is hooked up, more throttle is opened given comparison to stock rack.
Mine I'm using the stock bell crank which works out to be very close to stock throw.

 

[skiri251]

I have no bell crank.
I made up my own throttle arm and only use pull cable.

I need to twist the grip all the way for WOT so that is not good for off idle acceleration.
And maybe that's why I don't have bogs with less plenum heat?

 

[dan filipi]

Curious. What is the measurement from throttle plate center to your cable attachment hole?
Mine is 1" which gives me about 3/8 rotation of the grip from idle to WOT.

 

[joedrum]

hmmmm yes that throw looks long compare to mine ...I use the stock carb linkage ...how dose the lengths compare

 

[Ansimp]

Don't tell me that the reason the single carb instal seems to go so well is now down to throttle geometry. The big difference between the CBRs and the GoldWing throttles is you barely move your wrist and you get full throttle where on the GW I need to almost take two bites to get full throttle.
I was talking to a guy that has an Oz Trike (VW based) and he was saying how with his fused wrist the trike was so much easier to ride due to throttle actuation ( and it doesn't go to sleep if brain fade ( fall over)). I showed him the CBR's throttle and he was blown away by how easy and how little twist was required for full throttle.

 

[dan filipi]

Throttle geometry can be part of it depending on the degree twist. It is not the only part.
Lag in throttle slides is another part of the whole.

 

[skiri251]

Okay, so I shortened the throttle arm by half inch or so and went test ride again.
More tendency to bog when engine was cold.
When it warmed up to 100F+ plenum temp. I felt "neck breaking" :hihihi: acceleration so how fast you can open the throttle definitely matters.
But overall the response was jerkier than yesterday. Maybe I should go back to the previous arm.

But something strange happened today. The engine hesitated mid corner followed by huge after fire (bang). Felt like it ran out of gas (I filled it up
yesterday). It happened three times with petcock "on" position. I switched it to "reserve" and no bang. So this must be clogged petcock, right? Not related to the arm length change...

 

[dan filipi]

Sounds like clogged petcock.

The stumble:
What I think:
1. The engine is not keeping up with the air fuel charge being presented to it.
or
2. The AF charge isn't atomized well for the engine to take advantage of it.
or
3. The idle or primary jetting could use a tweak, trying a step richer.

( I reserve the right to think of something else. Long day at work, LOL.)

I've had similar problems that heat and jetting took care of.

BUT, I would first sort out what caused that backfire and maybe fuel delivery problem.

 

[skiri251]

Yes, I will take apart the petcock. Don't want that hesitation happen on I-405. :shock:
And maybe make another arm middle of the two length-wise.

 

[skiri251]

It seems that the gas cap vent was clogged.
I disconnected the fuel hose to drain the gas tank and fuel flow stopped in a minute.
When I opened the gas cap, it started flowing again.

So how should I clean the gas cap vent?
I see two holes inside but don't see any holes outside...

 

[slabghost]

This is common to motorcycles in general. Many have just drilled a tiny hole through the cap.

 

[skiri251]

Tried to unclog the vent with thin wire and carb cleaner but didn't work.
So drilled two holes.
Went to the mini-twisty again.
All is well.
What a pleasure!

Thanks again for all the help!

 

[slabghost]

Congrats! Can't wait to hear how you and Dan get it dialed in.