intake manifold issues

islandboy312 · 07-05-2009, 11:57 PM

Hi. I have a 2006 Roketa RSM200E with 1500 miles on it. It's been struggling for a few months. It has symptoms of a vacuum leak, mainly an erratic idle, also a bit of pinging and surging.

I've done a serious, stone cold valve adjustment, .005" intake and exhaust, more than spec, I know, but just to be sure...

The carb has been off a dozen times, it's extremely clean. Pilot screw set from 1/2 turn out to 2-1/2 turns out, no joy. New gas.

The intake manifold has several thousand cracks in it, like an old tire left out in the sun, and when the bike idles, it pulsates like a beating heart. I sprayed ether all over the manifold junctions (out of carb cleaner because the carb is so clean) and the manifold itself. There were no explosions.

The manifold junctions are tight. Soaking the body of the manifold itself, the idle stabilized momentarily, until the ether evaporated.

I bought a new intake piece from Roketa. It's too short by about 1/4". The carb hit the starter connection grommet. No worries, run it. The choke cable got hot! I put on another ground wire and removed the short intake.

Sorry to be so long-winded. A Honda manifold doesn't fit, not even close.
The Roketa parts people admit that parts for an early (?) model are a problem to get right.

Has anyone gooped up a leaky intake with magic stuff? Maybe the black weatherstripping goop? When you serious guys do bigger carbs, what do you do for intake connections? I'd love some new ideas before I burn my engine down! 70 mpg is too good to leave parked.

Many thanks - Dan

07-05-2009, 11:57 PM	#1
islandboy312 Join Date: Jul 2009 Posts: 13	intake manifold issues Hi. I have a 2006 Roketa RSM200E with 1500 miles on it. It's been struggling for a few months. It has symptoms of a vacuum leak, mainly an erratic idle, also a bit of pinging and surging. I've done a serious, stone cold valve adjustment, .005" intake and exhaust, more than spec, I know, but just to be sure... The carb has been off a dozen times, it's extremely clean. Pilot screw set from 1/2 turn out to 2-1/2 turns out, no joy. New gas. The intake manifold has several thousand cracks in it, like an old tire left out in the sun, and when the bike idles, it pulsates like a beating heart. I sprayed ether all over the manifold junctions (out of carb cleaner because the carb is so clean) and the manifold itself. There were no explosions. The manifold junctions are tight. Soaking the body of the manifold itself, the idle stabilized momentarily, until the ether evaporated. I bought a new intake piece from Roketa. It's too short by about 1/4". The carb hit the starter connection grommet. No worries, run it. The choke cable got hot! I put on another ground wire and removed the short intake. Sorry to be so long-winded. A Honda manifold doesn't fit, not even close. The Roketa parts people admit that parts for an early (?) model are a problem to get right. Has anyone gooped up a leaky intake with magic stuff? Maybe the black weatherstripping goop? When you serious guys do bigger carbs, what do you do for intake connections? I'd love some new ideas before I burn my engine down! 70 mpg is too good to leave parked. Many thanks - Dan
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