MM billet intake, carb, and clutch cable issues

jpullen · Nov 28, 2013

I just got a mm billet intake from JNM motors for my Grubee Skyhawn to use with my CNS carb. The bowl and overflow hose are hitting the clutch cable anchor and preventing me from being able to seat the carb all the way. I have searched for related threads but most were archived and links didn't exist anymore or thread hijacking rendered them useless. One said to grind down the anchor and another Said to put a plug in the hole. Any one have advice or a link? This is not a CNS billet with the 40mm stud spacing it is a regular small one with a 30mm stud spacing if that is relevant.

:-||

maniac57 · Nov 28, 2013

You could do something like this:http://motorbicycling.com/showthread.php?t=50466
Or simply grind the anchor shorter if you have only a bit of interference....

2door · Nov 28, 2013

That cable stand-off height is adjustable. Loosen the jam nut, back it off a little and the stand-off (anchor) can be threaded in deeper which might allow you the space you need.
There are also alternative ways to secure the clutch cable and not use the stand-off at all in which case you can plug the hole with a 1/4 pipe plug.

Tom

MotorBicycleRacing · Nov 28, 2013

jpullen said:
I just got a mm billet intake from JNM motors for my Grubee Skyhawn to use with my CNS carb. The bowl and overflow hose are hitting the clutch cable anchori

The Manic Mechanic billet intake is supposed to come with instructions to cut as much as you can off the clutch cable holder with a hack saw so you can screw it down into the case to give you clearance.

I don't think the billet intake sold by JNM is even made by George at Manic Mechanic so they should come up with a new name.

Jim originally sold his billet intakes with a cut down cable holder or whatever it is calied.

There is absolutely no need to use any kind of alternative clutch cable routing method.
The vendors selling straight intakes should include some basic instructions.

jpullen · Nov 29, 2013

The jam nut was all the way up that was my first adjustment. I hate to cutting and straightening anything fine thread if I have a choice so I matched up a 1/8" thick price of aluminum and cut a spacer and two extra gaskets to move billet back. With gaskets and rvt sealant do you think that will find off any air leaks? I haven't been able to try it out because im re-mounting my motor to try and cut down on vibration and level my car out a bit.

2door · Nov 29, 2013

How are you planning to "cut down on vibration"? If you're considering rubber, don't do it. It will not eliminate vibrations but will in fact simply transfer them to the engine mounts and fasteners and they will eventually fail. Mount the engine as solidly as possible. No rubber!

You can space out the manifold if needed but the gasket is the important factor. You can't have any air (vacuum) leaks downstream of the carburetor. Whatever it takes to seal up your modification, do it.

Would it be possible to post a photo of your engine with a close up of your clutch cable interference problem. We might be able to offer some alternatives.

Tom

jpullen · Nov 29, 2013

NO RUBBER! I am removing the rubber that was on the old mount. After reading several of your posts Tom. I'm using a muffle mount with steel plate from SBP on the front and a 1/4 aluminum on the rear of te motor with parts from the kit attaching it o the frame. I will take pictures of the carb clearance and post them on Tuesday. Work gets in the way of my hobbies some time. Thank for te help all.

MotorBicycleRacing · Nov 29, 2013

jpullen said:
The jam nut was all the way up.

If you removed the jam nut would that have allowed you to thread the cable holder down far enough to clear?
Cut the threaded section down with a hacksaw.
Leave the nut on the thread and use the face of the nut to get a straight cut with the hacksaw blade.

When you thread the nut off it will clean up the threads of the cut end.

Please post a pic.

jpullen · Nov 29, 2013

Without the nut the bolt binds on the shaft going from clutch to sprocket on te left side of he bike. At least thats what it looked like but what ever t was the bolt bottomed out o it and left scratch marks. I have used a nut to clean up cut off bolts before on my exhaust allen bolts but the threads seem mighty fine on this. If I mess it up does any one sell them?

2door · Nov 29, 2013

Instead of using a hack saw I'd grind the excess threads off. Lots less chance of buggering things up but use the jam nut to clean up the end of the threads. A bench grinder, side grinder with a cut-off wheel or disc would do the job neater than sawing. You shouldn't ruin it. Just take your time.

Tom

jpullen · Dec 4, 2013

I ground half the stud off and removed the nut. It gave me just enough to get it on with a 1/16th inch to spare. My phone doesn't want me to post pics today but I will try to get them added in case any others have this issue and need a visual reference. Cleaning the threads wasn't to bad it just took a razor and 400 grit diamond file to remove the rolled over steel edges. Thanks for the help all. Now to finish the new mount I want to ride again.

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MM billet intake, carb, and clutch cable issues

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