Another good $2 TwinMax substitute

[SlideRuyle]

I built one of these when I had my vstar 1100 and it worked quite well until I let the plastic hose drop on the hot exhaust pipe. I used 2 cycle motor cycle oil for fluid. I got a yard stick from the hardware store and 5/16th OD plastic tubing that was 3/16th ID. At the local O'reilys auto store got some 3/16ths in line air restrictors that I put in the tubing. Instead of the wire mentioned above I got some clamps made for the 5/16th tubing from the hardware store that I could attach to the yard stick. All total I spent about 10 bucks counting the oil.
Slideruyle

[riceburner]

Think I c0cked up on mine.

I used 3mm ID tubing and 3-in-1 oil to make it last night and to be quite honest - I think the ID is too small to let it bleed out properly. (ie to let all the air-pockets get out)

that's what you get for trying to be clever.

Any suggestions, or should I start again from scratch?

[Gordium7]

Slight variation that I did on mine.

Use clear tubing along the meter/yard stick. Use solid rubber vacuum or fuel line to go from end of clear tubing to the TBs (or carbs). Use a barbed tubing connector for joining the two.

I went with this because the rubber lines are not heat sensitive. My other bike is a twin carbed v-twin (Vstar) and I leave the rubber bits on the engine as I let it warm up -- trying to put them on after the engine is hot almost guarantees a burn or three because of the tight space on a v-twin. The rubber also is more more durable/resilient than clear vinyl and will behave itself after *many* uses.

As a suggestion, use diesel fuel as your oil. If any gets in the engine, all you get is a bit of smoke. It seems to have a good vicosity and density characteristics.

I also put a barb connector at the bottom of the stack between the left and right sides of the clear tubing. The smaller diameter acts to dampen oil movement between the two sides somewhat -- the diesel oil bounces around less so you can get a better "average" reading since it seems pretty sensitive.

[riceburner]

Think I c0cked up on mine.

I used 3mm ID tubing and 3-in-1 oil to make it last night and to be quite honest - I think the ID is too small to let it bleed out properly. (ie to let all the air-pockets get out)

that's what you get for trying to be clever.

Any suggestions, or should I start again from scratch?

My thoughts are to get a 2m length of wider tubing (that the 3mm ID tubing will fit into snugly) and use this for the "loop" section on the board. Good idea???

[CycleRob]

WOW. This is a revived post from May 24, 2006 (see the beginning)

I used 15 feet of 1/8th inch tubing that plugs directly on to the TB vacuum pipes. I thought it would be too long and I'd have left-over piping, but 15' is what you need. It works best when the manometer is filled half full so one side's rise to the top doesn't draw in air on the other side.
I got the yardstick and tubing from a True Value Hardware store very very cheap. I drilled thru the yardstick on each side of the held together tubes and wired them to the stick. When the tubes touch each other for the full length, there is no parallax error that any space could have. It's so easy to see any difference. I also put a plastic 2" diameter wheel on the bottom so the tubing can all be stretched tight around the bottom wheel and to the top of the stick. Using the metric side of the yardstick for the tubing, it looks like it's factory made. I will bring it, and a boxfan, to the bash this May. I hope we'll be too busy riding and eating to use it.

Since the tubing is such a tiny ID, using ATF (10W oil) was a very sluggish disaster. I switched it to WD-40 and that works good. I recommend food color dyed rubbing Alcohol if you use the small 1/8th inch pipe like I did. Using rubbing Alcohol will prevent bacterial growth that will cloud the tubing and it'll be OK if the engine eats it if there's initially a wacked-out synch.

EDIT:
Switched to 4 drops of green food coloring added to water with about 50% rubbing alcohol added. I put that mixture in a small nasal spray bottle with the internal pipe removed. Using the manometer, the response is fast. It's expendable. It's real cheap to make. Here's the kicker: It's more accurate and easier to read than ANYTHING else!!

[riceburner]

How do you fill 3mm ID tubing without getting air bubbles??

mine's been sitting for 3 nights now with 3-in-1 oil in it and it's chock full of air bubbles, the tube walls are too thick to squeeze it to help fluid along - I can drain it off I guess, but hwo to refill it without bubbles???