installing carb on manifold

Norman

Norman

LORD VADER Moderator
Easy way to make a leak free carb to intake manifold.
Light coat of silicone rtv on intake manifold but do not get the stuff on the very end of the manifold you don't want it in the carb.
Take your carb and push it on the intake manifold and just as you get it almost all the way on twist it a little and try to line up the casting seam on the carb with the casting seam on the manifold. While holding it in place tighten up the carb mounting bolt. You can ride it now or wait a day. To check for a good seal while engine is running spray the seal area with carb cleaner or starting fluid a change in rpm will mean you need to do it again which I have not had to do again as it worked every time so far.
Norman
 
yep I did this like a month ago and it worked out great.

I found though that the stock bolt was kind of lame to tighten (trying to hold one end with a screwdriver). When I get around to it, I'm going to try to find a better one.
 
Norman said:
Easy way to make a leak free carb to intake manifold.
Light coat of silicone rtv on intake manifold but do not get the stuff on the very end of the manifold you don't want it in the carb.
Take your carb and push it on the intake manifold and just as you get it almost all the way on twist it a little and try to line up the casting seam on the carb with the casting seam on the manifold. While holding it in place tighten up the carb mounting bolt. You can ride it now or wait a day. To check for a good seal while engine is running spray the seal area with carb cleaner or starting fluid a change in rpm will mean you need to do it again which I have not had to do again as it worked every time so far.
Norman
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I just did this to my bike. My bike laggs alot of speed... my kit use to be really fast... (34 mph)
but I moved it over from my speed bike to a cruiser which is now hitting... I would guess 15 mph And would Idle Rediculously high... so i did the carb cleaner trick to find a leak.. and i spayed it near the manifold and my idle dropped some.. So I did the sealing trick and now my Idle is AWESOME.. I can hear the true sound of my new SBP expansion muffler. it sound great. But the speed problem persist.
it seems like its not getting enough fuel or something.. my sparkplug is burning tan and the clip is on the first notch on the needle. it has a drastic loss of speed and power then gains it back, then drops again.... dunno why. like i said its only toping out at about 15 mph or so...
 
vwine said:
I just did this to my bike. My bike laggs alot of speed... my kit use to be really fast... (34 mph)
but I moved it over from my speed bike to a cruiser which is now hitting... I would guess 15 mph And would Idle Rediculously high... so i did the carb cleaner trick to find a leak.. and i spayed it near the manifold and my idle dropped some.. So I did the sealing trick and now my Idle is AWESOME.. I can hear the true sound of my new SBP expansion muffler. it sound great. But the speed problem persist.
it seems like its not getting enough fuel or something.. my sparkplug is burning tan and the clip is on the first notch on the needle. it has a drastic loss of speed and power then gains it back, then drops again.... dunno why. like i said its only toping out at about 15 mph or so...
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its getting too much gas try going alittle less on fuel cock i did that too mine no more bogging or cut outs !!!
 
kla63 said:
its getting too much gas try going alittle less on fuel cock i did that too mine no more bogging or cut outs !!!
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KLA63,

Holy crap... That was all it was this whole time...
I just went out and opened it only a quarter of a turn instead of half and BAM!!
I dont think I have ever gone that fast on one of these things...
SO SO Fun and scary lol, you were exactly right, and it didnt bogg at all.. it felt like unlimited power.. the only thing keeping me from going faster was the vibration lol. Thanks alot man. VWxct2
 
vwine said:
KLA63,

Holy crap... That was all it was this whole time...
I just went out and opened it only a quarter of a turn instead of half and BAM!!
I dont think I have ever gone that fast on one of these things...
SO SO Fun and scary lol, you were exactly right, and it didnt bogg at all.. it felt like unlimited power.. the only thing keeping me from going faster was the vibration lol. Thanks alot man. VWxct2
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Your Welcome !!!! like i said find where yours runs good and remember the postion i mark mine with a sharpie i make a black line on pet cock that i can see looking down!!!! and in the earlier post i gave you just cut up anold inner tube !!!rap around where your mounts are that should take care of some off the vibration!!!! you can also fill your handle bars with sand that will take some vib out of your hands as well..... glad i could help enjoy your ride!!!!! if you have any questions drop me a line !!! [email protected] or gas bicycle motors Home dance1
 

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Guys,
The fuel petcock is NOT a fuel metering device. If restricting the flow helps your performance then you have other problems. Start with the float/needle & seat inside the carburetor. Typically a float that is set too high will allow a flooding, or rich fuel mix (too much fuel to air). Check for trash in the orifice of the needle valve and make sure the needle seats fully and shuts off the fuel as it is designed to do. Raise the clip on the main jet needle. This controls how far the needle is pulled from the jet. The more it is raised, the richer the mixture. The petcock should be full open and the carburetor controls how much fuel is delivered to the engine.
Tom
 
2door said:
Guys,
The fuel petcock is NOT a fuel metering device. If restricting the flow helps your performance then you have other problems. Start with the float/needle & seat inside the carburetor. Typically a float that is set too high will allow a flooding, or rich fuel mix (too much fuel to air). Check for trash in the orifice of the needle valve and make sure the needle seats fully and shuts off the fuel as it is designed to do. Raise the clip on the main jet needle. This controls how far the needle is pulled from the jet. The more it is raised, the richer the mixture. The petcock should be full open and the carburetor controls how much fuel is delivered to the engine.
Tom
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been there done that it never worked !!!!!! this works and there is no problems!!!!! plug exellant awsome power !!!! that what works for me on some bikes so thats what do !!!!! none of these motors are the same !!!!! these are cheap carbs not much too them four notch needle !!!! i've been working on these alot so that s what i do !!!!!! it work for him too !!!! you don't need that much gas too run these little motors !!!!!!!!!.wee. i have one bike with over 15,000 on it still running like a rocket with pet cock at a certin postion!!!!!
 
its getting too much gas try going alittle less on fuel cock i did that too mine no more bogging or cut outs !!!
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I've never heard anything like this before. 2door is right.
By using the fuel petcock as a metering device, you are risking serious engine damage.
If you turn it off a little too far, your engine will run extra-lean, causing overheating and potential seizure of the top end.

If the air/fuel mix is too rich, lower the slide needle a notch for low to 3/4 throttle, or, for WOT, try a smaller main jet.
Also check your float level - should be about 21mm for an NT carb and make sure the float needle valve is clear.

... Steve
 
Back on topic.
For those who don't mind a little extra work and will accept nothing less than perfect, this is the best way to seal the carb to the inlet, if you have an after-market alloy inlet.
I used a thin 'warding' file, on it's edge.
The groove should be as close as possible to the end of the tube. After cutting the groove in mine, I shaved the end of the tube slightly until the 'O' ring was about 1mm from the end.
It's a good idea to smooth the inside of the slots in the carb, too, so they don't damage the 'O' ring.

... Steve

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AussieSteve said:
Back on topic.
For those who don't mind a little extra work and will accept nothing less than perfect, this is the best way to seal the carb to the inlet, if you have an after-market alloy inlet.
I used a thin 'warding' file, on it's edge.
The groove should be as close as possible to the end of the tube. After cutting the groove in mine, I shaved the end of the tube slightly until the 'O' ring was about 1mm from the end.
It's a good idea to smooth the inside of the slots in the carb, too, so they don't damage the 'O' ring.

... Steve

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A Very nice bit of hand forming work Steve! I can appreciate what it took to do that.

Jim
 
Thanks, Jim.

Another good diagnostic tool is the choke.
If there's an air leak causing a lean mixture, turning the choke partly on will make the engine run better.

... Steve
 
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