Bike Carbs 4x32mm

General discussion about our beloved Tercel 4WD cars
PrescottAZ
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My tercel:: 83 4wd, jeep cherokee front springs in rear, cut fenders, mr2 booster, gauge swap for tach, Suzuki Katana 600 Carbs, 330,000 miles and ticking (literally)
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Bike Carbs 4x32mm

Post by PrescottAZ » Fri Jun 17, 2011 8:12 pm

Would bike carbs make the engine code a 3a4c or 3ac4? I know it is still the lowely 3ac but it would be cool to rename it.
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They are off an 01 katana 600. I cranked it and it did start but it ran pretty crummy due to fuel flowing out. Turns out either I need to do a rebuild on the carb or the fuel pump is overwhelming it with fuel pressure. I know they are gravity fed and the terc is supposed to be 7psi but they are more often 3psi and I thought there is a chance that I could get away with it. 32mm Mikuni. When I get around to solving the fuel issues I will post a running video. Pretty straight forward. $50 for the carbs and hacksawed the manifold bought some hose and clamps then installed.

Tercel__jon
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Re: Bike Carbs 4x32mm

Post by Tercel__jon » Fri Jun 17, 2011 8:46 pm

Thats badass. I thought about doing that to my cressida once...never thought about doing it to the tercel. it would be a pain to dial all of the carbs in, but once you did it would be sweet. Maybe even a couple more hp? Idk. Youve got me wanting to try it now though. hehe.

toughtercel
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Re: Bike Carbs 4x32mm

Post by toughtercel » Sat Jun 18, 2011 11:26 am

Neat , I though about to try same design set up like those late 60's or 70's Lotus's Webers/Intake .

4wdchico
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Re: Bike Carbs 4x32mm

Post by 4wdchico » Sat Jun 18, 2011 11:38 am

Air filtration?

PrescottAZ
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My tercel:: 83 4wd, jeep cherokee front springs in rear, cut fenders, mr2 booster, gauge swap for tach, Suzuki Katana 600 Carbs, 330,000 miles and ticking (literally)
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Re: Bike Carbs 4x32mm

Post by PrescottAZ » Sat Jun 18, 2011 12:25 pm

I will put cones on and I need to drop fuel pressure as well as hook up the throttle cable.

PrescottAZ
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My tercel:: 83 4wd, jeep cherokee front springs in rear, cut fenders, mr2 booster, gauge swap for tach, Suzuki Katana 600 Carbs, 330,000 miles and ticking (literally)
Location: Prescott Arizona
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Re: Bike Carbs 4x32mm

Post by PrescottAZ » Sat Jun 18, 2011 7:50 pm

Video:
http://www.facebook.com/v/1734724900825

It is only 29 seconds and I shot it with my phone so not the best quality.

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Petros
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Re: Bike Carbs 4x32mm

Post by Petros » Sun Jun 19, 2011 9:51 am

That looks like a hot set-up! Easy way to make a "custom" manifold too. Where did you get the carbs for $50? That is cheaper than replacing the stock carb. I am sure there are jets and things you can get to tune it to the Tercel engine. A fuel pressure regulator should drop the fuel pressure so the carbs can work properly.

Once you get it running good make a list of parts you used.
'87 Tercel 4wd SR5 (current engine swap project)
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PrescottAZ
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Posts: 115
Joined: Mon Nov 01, 2010 4:03 pm
My tercel:: 83 4wd, jeep cherokee front springs in rear, cut fenders, mr2 booster, gauge swap for tach, Suzuki Katana 600 Carbs, 330,000 miles and ticking (literally)
Location: Prescott Arizona
Contact:

Re: Bike Carbs 4x32mm

Post by PrescottAZ » Sun Jun 19, 2011 10:10 am

Craigslist: Katanas are viewed as B team so they are wicked cheap and they are Mikuni 32's from a 600cc.
The runners pulse from the vacuum and it looks very weird.

PrescottAZ
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Re: Bike Carbs 4x32mm

Post by PrescottAZ » Sun Jun 19, 2011 10:15 am

Oh and I have a heap of oily parts left over if anyone local wants or needs them

Tercel__jon
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Re: Bike Carbs 4x32mm

Post by Tercel__jon » Sun Jun 19, 2011 5:41 pm

Again very awesome. I was thinking about this the other day and shouldnt having 4 carbs, promote a more even distribution of fuel to each cylinder therefore increasing the efficiency of the engine? You know, a little more power or mpgs would never hurt.

arbskynxnex
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Re: Bike Carbs 4x32mm

Post by arbskynxnex » Mon Jun 20, 2011 6:57 pm

the 4ac powered forums has a bit of info on setting up bike carbs and the like for the 4ac most of which should apply to a 3ac. It might save you from reinventing the wheel on some things.
Pandas: Eats, shoots and leaves.

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Petros
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Re: Bike Carbs 4x32mm

Post by Petros » Mon Jun 20, 2011 7:51 pm

with the carbs jetted and tuned to the 3ac engine it should give you both better fuel economy and more max hp. If you keep your foot off of it the 4 carbs will have lower induction losses (engine has to work less hard to suck the fuel/air mixture into the cylinders), and provide more even fuel distribution, and better throttle responce too. With a single carb you almost always have the center two cylinders running a bit rich, and the end two (one and four) running a bit lean, this provides poor efficiency and poor emissions performance.

Interesting to see that each carb has a larger barrel than the stock carb on the 3ac, so you have more than twice the throttle area and barrel cross sectional area. It came off an engine less than half the size of the 3ac. Just shows you how inefficient and obsolete the 3ac engine is compared to more modern designs.

gets some stiffer hoses on that manifold, it will improve the vacuum at the carbs, better mixture, than with ones that pulse with the engine vacuum.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)

shogun
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Re: Bike Carbs 4x32mm

Post by shogun » Tue Jun 21, 2011 7:48 am

and remember those type of carbs have to be pointing at a slight angle, iirc 30° so the float can seat level, and try to get some velocity stacks it will improve on the low end and up top, not that youd want to be up top too much on a stock head
tercel 4wd custom suspension, under drive pulley, vented brakes, cold air intake, and plenty more to come

4wdchico
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Re: Bike Carbs 4x32mm

Post by 4wdchico » Tue Jun 21, 2011 10:58 am

shogun wrote:and remember those type of carbs have to be pointing at a slight angle, iirc 30° so the float can seat level, and try to get some velocity stacks it will improve on the low end and up top, not that youd want to be up top too much on a stock head
The cheapest route for some tuned velocity stacks would be to adapt the stock airbox that those carbs came with. I was a pro motorcycle wrench back in the day and much preferred to mod the air filter that supplied air to a stock airbox than the individual pod setup.

Shogun's comment about the correct angle on the carb set is solid. Have you got the carbs secured to the engine so they don't get to whipping around on the end of the intake hoses when motoing?

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Re: Bike Carbs 4x32mm

Post by shogun » Wed Jun 22, 2011 9:19 pm

i tuned a vw rabbitt with a cross flow head a long time ago, and no matter what we did the car flooded, took a look in a bike the carbs came from, meassured the angle and then we had it running perfectly
tercel 4wd custom suspension, under drive pulley, vented brakes, cold air intake, and plenty more to come

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