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

mblas3 · 07-06-2009, 08:00 AM

Does this intake manifold look like what you have?

Hopper Imports Intake

M

Cal25 · 07-06-2009, 08:07 AM

You might try to coat the manifold with RTV silicone. I think it is safe with gas. I bet someone comes up with a source for a new one.

katoranger · 07-06-2009, 10:07 AM

Quote:

Originally Posted by Cal25

You might try to coat the manifold with RTV silicone. I think it is safe with gas. I bet someone comes up with a source for a new one.

Successfully did this on a yamaha until I could find new boots. It worked for a year with no problems.

Allen

FastDoc · 07-06-2009, 11:15 AM

Has anyone gooped up a leaky intake with magic stuff? Maybe the black weatherstripping goop?

Yes, on a Honda 100. worked fine. Black RTV silicone.

islandboy312 · 07-06-2009, 02:55 PM

Thanks, guys. I'll be buying the unit mblas3 suggested. in the meantime, I'll do a few goop experiments and report back.

Thanks for the help - Dan

HotelRed · 08-26-2009, 03:14 PM

Islandboy312, did you get the manifold? Did it fit? It looks a tad long to me.
I have the same bike with all the cracks & want to fix it.

John

Reveeen · 08-26-2009, 06:01 PM

Help me here please.

I simply do not "get" why the Chinese are seemingly in love with flange mount carbs. Would it not be simpler to use a spigot mount and a spigot carb?

undertulsa · 08-26-2009, 10:11 PM

My intake box has a small hole where the Chinlee goop let the hose slide prob. during production. Gonna goop some more goop on it to fill it in.

HotelRed · 09-28-2009, 10:46 AM

I finally got mine fixed. 2005 Roketa RSM 200E.

Pic of the bike:

I got the manifold from here: http://www.buyatvsonline.com/ $27.90 shipped.

Pick of both manifolds:

You may want to cut a little off the studs as they are a bit too long. I did not.
Installation was easy but the new one is not EXACTLY the same dimensions. A tad shorter with less angle. The result is the airbox hose does not match up with the carb. No way to fix it so the stock airbox had to go.

Pic of airbox offset (notice the top shock mount also, it is a lot closer then it looks):

I tried to use a UNI 2 stage filter but the top shock mount will not allow access to the back of the carb. I was reduced to using a UNI sock filter (1-1/2" by 4"). Not happy with this but will use it til I can figure out how to fabricate a proper airbox to protect the filter.

Pic of sock filter installed:

That is all I can think of at the moment.

John

FastDoc · 09-28-2009, 11:09 AM

I did the same trick on an XR 100 and it worked great. Not professional looking, but sometimes pros are hacks too. :evil:

Weldangrind · 09-28-2009, 11:57 AM

HotelRed,

If you're going to use a pod filter, try a dual-layer for maximum protection. They're ususally around $20 from the local bike shop.

They're available in straight or 15 degree angle. Check out http://www.unifilter.com/online%20ca...universal.html

Weldangrind · 09-28-2009, 12:11 PM

John,

Can you adapt the original elbow from the stock box to connect to a pod? Perhaps you can angle the elbow to get around the shock mount.

Is the sock flange different from the dual layer flange?

HotelRed · 09-28-2009, 12:11 PM

weldangrind

Thanks but I tried both the straight and angled due to one of your previous posts. The top shock mount is so close to the carb that it will not allow the flange to get to the carb. That is why I had to use the sock filter.

Hard to see in the pic but it is right up there under the carb opening.

John

islandboy312 · 10-13-2009, 02:23 PM

Still dinking around with the original inlet tube, and the vacuum leak. I looked at the o-ring that seals against the head. It was flat and did not protrude past the flange surface of the intake tube. I pulled a new o-ring out of a no-fit intake tube and put it in my original tube. Huge improvement.

I'll be looking for a Viton o-ring of the same size. That material should be a bit more heat-resistant. This could be a problem even with a good intake tube.

Hotelred, I left the plastic off my bike too. I like it better.

Thanks, guys.

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
	0

07-06-2009, 11:15 AM	#5
FastDoc Join Date: Mar 2009 Location: Southeastern Washington desert Posts: 14,761	Has anyone gooped up a leaky intake with magic stuff? Maybe the black weatherstripping goop? Yes, on a Honda 100. worked fine. Black RTV silicone. __________________ Happy to serve.
	1

07-06-2009, 02:55 PM	#6
islandboy312 Join Date: Jul 2009 Posts: 13	Thank you Thanks, guys. I'll be buying the unit mblas3 suggested. in the meantime, I'll do a few goop experiments and report back. Thanks for the help - Dan
	0

08-26-2009, 10:11 PM	#9
undertulsa Join Date: May 2009 Posts: 219	HOLE My intake box has a small hole where the Chinlee goop let the hose slide prob. during production. Gonna goop some more goop on it to fill it in.
	0

09-28-2009, 11:09 AM	#11
FastDoc Join Date: Mar 2009 Location: Southeastern Washington desert Posts: 14,761	I did the same trick on an XR 100 and it worked great. Not professional looking, but sometimes pros are hacks too. :evil: __________________ Happy to serve.
	0

07-06-2009, 08:00 AM	#2
mblas3 Join Date: Mar 2007 Posts: 120	Does this intake manifold look like what you have? Hopper Imports Intake M
	0

07-06-2009, 08:07 AM	#3
Cal25 Join Date: Feb 2008 Location: Terrell and Grapevine Tx. Posts: 1,585	You might try to coat the manifold with RTV silicone. I think it is safe with gas. I bet someone comes up with a source for a new one.
	0

08-26-2009, 03:14 PM	#7
HotelRed Join Date: Jul 2006 Location: Payson, AZ Posts: 53	Islandboy312, did you get the manifold? Did it fit? It looks a tad long to me. I have the same bike with all the cracks & want to fix it. John
	0

08-26-2009, 06:01 PM	#8
Reveeen Join Date: Jun 2009 Location: orbital platform Posts: 741	Help me here please. I simply do not "get" why the Chinese are seemingly in love with flange mount carbs. Would it not be simpler to use a spigot mount and a spigot carb?
	0

09-28-2009, 10:46 AM	#10
HotelRed Join Date: Jul 2006 Location: Payson, AZ Posts: 53	I finally got mine fixed. 2005 Roketa RSM 200E. Pic of the bike: I got the manifold from here: http://www.buyatvsonline.com/ $27.90 shipped. Pick of both manifolds: You may want to cut a little off the studs as they are a bit too long. I did not. Installation was easy but the new one is not EXACTLY the same dimensions. A tad shorter with less angle. The result is the airbox hose does not match up with the carb. No way to fix it so the stock airbox had to go. Pic of airbox offset (notice the top shock mount also, it is a lot closer then it looks): I tried to use a UNI 2 stage filter but the top shock mount will not allow access to the back of the carb. I was reduced to using a UNI sock filter (1-1/2" by 4"). Not happy with this but will use it til I can figure out how to fabricate a proper airbox to protect the filter. Pic of sock filter installed: That is all I can think of at the moment. John
	0

09-28-2009, 11:57 AM	#12
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	HotelRed, If you're going to use a pod filter, try a dual-layer for maximum protection. They're ususally around $20 from the local bike shop. They're available in straight or 15 degree angle. Check out http://www.unifilter.com/online%20ca...universal.html __________________ Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer
	0

09-28-2009, 12:11 PM	#13
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	John, Can you adapt the original elbow from the stock box to connect to a pod? Perhaps you can angle the elbow to get around the shock mount. Is the sock flange different from the dual layer flange? __________________ Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer
	0

10-13-2009, 02:23 PM	#15
islandboy312 Join Date: Jul 2009 Posts: 13	Manifold O-ring Still dinking around with the original inlet tube, and the vacuum leak. I looked at the o-ring that seals against the head. It was flat and did not protrude past the flange surface of the intake tube. I pulled a new o-ring out of a no-fit intake tube and put it in my original tube. Huge improvement. I'll be looking for a Viton o-ring of the same size. That material should be a bit more heat-resistant. This could be a problem even with a good intake tube. Hotelred, I left the plastic off my bike too. I like it better. Thanks, guys.
	1