General Bike carbs
- Thread starter jimmy 2.1
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General Bike carbs
Brooky has done an individual TB set up. Waiting for Megasquirt to get it to run.
Problem is getting TBs (let alone carbs) small enough. For most mortals a single 40mm Tricker is enough!
Problem is getting TBs (let alone carbs) small enough. For most mortals a single 40mm Tricker is enough!
My ITB's
Not finished the inlet manifold off yet, really need to finish it off and get welding
Not finished the inlet manifold off yet, really need to finish it off and get welding
Eccentric_Rich
New member
What engine is that Brooky? I don't recognise the cam cover.
Thanks,
Richard.
Thanks,
Richard.
Tubes are so long because i have finish it yet, i thought id rather make them too long than abit too short, they will be chopped down abit when it comes to welding then to the flange.
Bodies are from a F4i i think
Engine is a 1242 16v, just in there to get all the sized right, will eventually be a 1368
Brooky aint you worried they might be a little big and the injectors flow far to much? im looking out for some from a 400CC bike as these are likely to be a better size (maybe just a LITTLE to big)
Also somewhere out there is someone making ITBS for the fire engine. ive been asked to fit an ecu on a engine with a set on a rally cento
Also somewhere out there is someone making ITBS for the fire engine. ive been asked to fit an ecu on a engine with a set on a rally cento
The injectors will be too small -- will need to run at a higher duty cycle. Typically, bike carbs are way too lean when put on a car.
The TBs are too big, but may be useable.
I'd look for TBs off a 250 or 400, but as those were all grey imports, they're very hard to find.
Interesting to know who's doing ITBs, but everything suggests that there is no advantage except at peak revs (and on a very cammy engine) over a decent plenum and single TB and MPI. Add to that that the FIRE engines don't make great high reving motors (long stroke, especially on post 1108 ones), heavy valve train (shim in bucket rather than shim under bucket) and even hydraulic tappets on the 16v ones.
The TBs are too big, but may be useable.
I'd look for TBs off a 250 or 400, but as those were all grey imports, they're very hard to find.
Interesting to know who's doing ITBs, but everything suggests that there is no advantage except at peak revs (and on a very cammy engine) over a decent plenum and single TB and MPI. Add to that that the FIRE engines don't make great high reving motors (long stroke, especially on post 1108 ones), heavy valve train (shim in bucket rather than shim under bucket) and even hydraulic tappets on the 16v ones.
The injectors will be too small -- will need to run at a higher duty cycle. Typically, bike carbs are way too lean when put on a car.
The TBs are too big, but may be useable.
I'd look for TBs off a 250 or 400, but as those were all grey imports, they're very hard to find.
Interesting to know who's doing ITBs, but everything suggests that there is no advantage except at peak revs (and on a very cammy engine) over a decent plenum and single TB and MPI. Add to that that the FIRE engines don't make great high reving motors (long stroke, especially on post 1108 ones), heavy valve train (shim in bucket rather than shim under bucket) and even hydraulic tappets on the 16v ones.
The TBs are too big, but may be useable.
I'd look for TBs off a 250 or 400, but as those were all grey imports, they're very hard to find.
Interesting to know who's doing ITBs, but everything suggests that there is no advantage except at peak revs (and on a very cammy engine) over a decent plenum and single TB and MPI. Add to that that the FIRE engines don't make great high reving motors (long stroke, especially on post 1108 ones), heavy valve train (shim in bucket rather than shim under bucket) and even hydraulic tappets on the 16v ones.
thing is most smaller fours are old bikes and have carbs(altho i thought i wont be hard to mod these to work as there vacume carbs. just block off the ports and emulsion tube and remove the slides then use normal fiat mpi injectors)
yeh the itb are only really good for high rev engines like bikes or lumpy cams with loads of overlap
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steve handley
New member
you needc carbs off a 1000 like a r1 or a fireblade dont you 38mm to 40 mm if there off a 400 they will be to small the injectors are in the inlet manifold that you are removing.
you need to turn the fuel pump down so they do not flood the engine?
i got told by a company that cnvert cars to carbs that the longer the inlet manifold the more torque you get.
also i thought the ecu war left on that car for everything else not the fuel as carbs are sucksion and gravity fed
you need to turn the fuel pump down so they do not flood the engine?
i got told by a company that cnvert cars to carbs that the longer the inlet manifold the more torque you get.
also i thought the ecu war left on that car for everything else not the fuel as carbs are sucksion and gravity fed
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carbs or tb from a 1000cc bike would be WAY to big. opening them only a bit would be like full throttle. (you shouldnt really have tb/carb that flows more then the head ever will as this will happen)
but your right about the ECU and carbs. if you can make the ecu think it is still injecting fuel it will be happy. wont take much at all.
on the other hand (some might bite my head off for saying this) but a propper fuel injection setup is much better then a carb. fuel injection can take in account for any variables that a carb will never be able to do. and what would take HOURS on a dyno to tune with a carb can be done to a good level in an hour on a drive way:devil:
steve handley
New member
haha injection is more everyday use int it
1000cc bike carbs are the right size for an engine of that size revving to 10'000 rpm or higher, on an engine revving to 7200 max, assuming a standard limiter, you need something much smaller. Working out the actual required sizing of the carb/TB and runners is very complicated thing to do. In all honesty you'd probablly be better off guesstimating from it 'feels right' rather than trying to work it out.
Injection will produce the same or better power, torque & throttle response in an engine if setup properly, this includes the manifold setup & injector placement. Ideally you want to have a properly mixed air stream passing over the throttle plate for peek power but for partial opening throttle response you want injectors somewhere between the throttle plates and the inlet ports, the lower the rpm the closer to the inlet ports you want the injectors. Obviously with carbs they mix the fuel close to the throttle plate thus are naturally optimised towards peek power & hence the reason people, erroneously, say carbs are better for all out power.
Injection will produce the same or better power, torque & throttle response in an engine if setup properly, this includes the manifold setup & injector placement. Ideally you want to have a properly mixed air stream passing over the throttle plate for peek power but for partial opening throttle response you want injectors somewhere between the throttle plates and the inlet ports, the lower the rpm the closer to the inlet ports you want the injectors. Obviously with carbs they mix the fuel close to the throttle plate thus are naturally optimised towards peek power & hence the reason people, erroneously, say carbs are better for all out power.
