Bore Stock 650sx Intake Manifold?

Codenamecody · 02-18-2010, 05:37 PM

I read that group K bores the stock intake manifolds when upgrading to a 38mm.

Quote:

This conversion is a snap since the stock 28carb and 38carb have the same bolt pattern, and the stock throttle cable hooks right up to the bigger 38. We simply bored the stock inlet manifold to 38mm for the new carb. Even the stock flame arrestor case matched up perfectly to the new 38…. And the True Bore 38 offered a clear improvement in throttle response over the tiny stock 28mm carb.

Is there any way I could do this at home? I have a drill press and a dremel tool if those would come in handy. I thought I remembered reading a thread about this a long time ago but I can't find it now.

Thanks,
Cody

upstand2 · 02-19-2010, 11:26 AM

Sure , just match it to a 38 carb gasket.

bkoche · 02-19-2010, 12:42 PM

Take your time and do it cleanly. Remember its hard to add material back on

octane114 · 03-04-2010, 05:36 PM

if you had a small cylinder hone, that would work as well

DBLOCK · 03-07-2010, 12:45 AM

I opened up the bore in my exhaust manifold as follows:

Trace the outline of the exhaust gasket on to the flange.
using a die grinder with a cylindrical sanding bit - removed material until the bore matched the line. I extended the bore down into the manifold as far as I could.

I would assume you could do similar with the intake manifold.

rivermann · 03-08-2010, 01:23 PM

i have done it and it works pretty good

tokarzl · 03-08-2010, 01:38 PM

use a dremel that worked great on mine just go slow and take your time

monster 550 · 04-13-2010, 05:53 PM

Great question. So just bore as far down as you can? Only bore the carb inlet?

KawiJS550 · 04-13-2010, 05:58 PM

bore and port as far down as you can - don't leave sharp edges or burrs; make it a nice, flowing hole.

OR - I'll sell you a stock 38mm 650 intake mani that you just have to bolt on - your call. PM me if interested.

rivermann · 04-13-2010, 06:54 PM

Thats what i did