Honda CX 500 Forum banner
1 - 20 of 20 Posts

·
Registered
Joined
·
220 Posts
Discussion Starter · #1 ·
Hello Folks, finished my restoration today. I will post pics soon. Bike is good as new. Gorgeous. Problem is when I drive it turbo

puts out very little if any boost. Gauge shows 2 bars to each side at about 4000 RPM. So my question for all you Turbo geniouses is:

any ideas how I can coherce the turbo into putting out more boost. As you may recall I live at 12000 feet above sea level. So, we have

less O2. Turbo should be a blessing but its not putting out the goods. Any idea will be considered/appreciated



THanks.
 

·
Registered
Joined
·
105 Posts
Might be a bit of a drive for you, but take the bike down to as close to sea level as you can. The turbos are not

adaptable, they just spin at whatever rate and whatever amount of air is available is what you get. That's why NOS

is so popular (not for you bike!), all it does is cool the air down so it is more dense and creates more horsepower.



That would be the easiest test to do.



Good luck.
 

·
Registered
Joined
·
658 Posts
Hello,



Is your turbo even spinning as it should? Sounds like you may have problems if no boost is being built up. Regardless of altitude you should be building boost. If not I think you have another problem..



PK
 

·
Registered
Joined
·
228 Posts
Does it have any power? I should be a complete dog with no boost. If it seems to make decent power, I would think your guage is not reading correctly. If in fact your guage is correct, I would guess that you have a problem with the wastegate being stuck open, a leak between the exhaust ports and the turbo, or a turbo that needs a re-build.
 

·
Registered
Joined
·
220 Posts
Discussion Starter · #5 ·
Thanks for the replies fellas. I am a bit uncertain about my Turbo. I feel very poor performance. How can I check if my turbo is indeed working? Is it totally mechanicaly driven or is there electronics involved.



When coasting down hill on gear I could hear the turbo whistling but not when I pin the accelerator. During regular driving I get no alarms on the computer. Idle is very smooth and engine sounds fine.
 

·
Registered
Joined
·
2,417 Posts
Rique,



I think we have talked about this a little in the past, obviously you did not get it fixed or settled. To start, I think your injection system does not operate that well at that altitude. It may be having trouble getting the proper mixture. If that happened you might not ever be able to reach proper boost, or the boost may be limited. As for your turbo, you really need to hook up a true boost gauge to verify output and performance. This is easiest on a dyno, but you can do it on a highway or uncrowded stretch of road. The boost should gradually start and build to 16-17 lbs. at redline. If it is not achieving this then you need to go back through all of the troubleshooting steps. A stuck wastegate is pretty common and might be fixed as easily as using a quality lubricant to get it functioning again. One other obvious thought is to get the bike to a lower altitude to check performance. If you could get down to 6,000 to 8,000 feet, this would be well within the range that the computer and sensors should operate properly. Good luck.
 

·
Registered
Joined
·
25 Posts
I would check the waste gate actuator and see if it is stuck. Remove the radiator screen and move the actuator arm from right to left, as you are looking at it. It should move with a little effort and then spring back to the original position. I needed to squirt mine with Mouse Milk ( a penetrating oil used in the aircraft industry) and let it sit overnight to free it up. Mouse Milk is recommend as it will handle the heat better that most penetrating oils.
 

·
Registered
Joined
·
220 Posts
Discussion Starter · #8 ·
Ed H, we did touch this issue before but it was cause I was getting codes on the computer. With them gone I figured Turbo was OK. Ad 1FTG posts I did check the waste gate but the actuator arm moves freely to an fro. I put a 12mm wrench on the actuator and I can move it back and it will bounce back.



What if I take the turbo off and give it a check. How is it driven? by a belt I beleive. It could have snapped!
 

·
Registered
Joined
·
3,612 Posts
One of my 500 turbos had a broken wastegate spring, and the wastegate opened almost as soon as I started developing boost.



I solved that problem with a boost valve. Very easy to install, $40.00 part. www.boostvalve.com

All you need is the universal kit, and some hose.
 

·
Registered
Joined
·
977 Posts
As you may recall I live at 12000 feet above sea level. So, we have

less O2.

THanks.


I cannot imagine much O2 at all at 12,000 feet altitude. I know that during my training as a private pilot it is absolutely necessary to be on Oxygen if you spend more than 30 minutes at anything between 10,000 and 12,000 feet of altitude. I don't think my Cpap machine would even work at that altitude. Where do you live? Inquiring minds want to know. Billrod
 

·
Registered
Joined
·
220 Posts
Discussion Starter · #11 ·
Tim,did you have to remove the turbo to install the valve? I live in La Paz Bolivia. I have other bikes (BMW S1000RR & R1100S) both work great, of course 30 years younger
 

·
Registered
Joined
·
220 Posts
Discussion Starter · #12 ·
I just recalled I have borescope. I wonder if I can channel it through the air filter intake and see if turbo spins. Then again I don't know if the Turbo puts out boost when bike is in neutral at idle and at a stand still...hmmm
 

·
Registered
Joined
·
2,417 Posts
Ed H, we did touch this issue before but it was cause I was getting codes on the computer. With them gone I figured Turbo was OK. Ad 1FTG posts I did check the waste gate but the actuator arm moves freely to an fro. I put a 12mm wrench on the actuator and I can move it back and it will bounce back.



What if I take the turbo off and give it a check. How is it driven? by a belt I beleive. It could have snapped!
Your turbo is not driven by a belt. The exhaust gas goes in one side of the turbocharger and spins it then goes out the exhaust pipe. On the other side, fresh air is sucked in and pressurized and forced through the intake and into the engine. We can throw a lot of "what ifs" at the situation but the bottom line is we need to know if the turbo is developing boost and how much. Pulling the turbo off won't do much as there is not much for you to examine if you do not know what to look for. If it is not at normal boost levels then we address the wastegate issue.



At 13,000+ altitude, I am still concerned about the bike's fuel injection abilities. Here in the US we seldom hear of riding at much more than 10,000ft, and I have concerns that your bike which was essentially a prototype for Honda is equipped to run well in Bolivia. Has the bike ever run well at altitude to your knowledge? It should have run much better than a normal CX500. It should have run like a 600 or 750 sportbike, which loses 40% of its horsepower at altitude.



Don in Oz, feel free to jump in here at any point.



Ed
 

·
Registered
Joined
·
3,612 Posts
Tim,did you have to remove the turbo to install the valve? I live in La Paz Bolivia. I have other bikes (BMW S1000RR & R1100S) both work great, of course 30 years younger


Nope, If I recall correctly, you only have to remove the chin plate, grill, and fairing. As you are looking at the engine from the front, the hose on the lower right of the turbocharger that controls the wastegate actuator is removed.

The boost valve is attached to the lower right radiator mount, hoses are connected to the nipples on the boost valve (the boost valve is directional, but the instructions are clear), and then the other side of the hoses are connected to the nipples on the turbocharger.



Basically, the boost valve is a pressure release system controlled by a spring and a ball bearing. When the pressure hits your predetermined limit (usually 19-19.5 lbs), the system releases the pressure, and your wastegate opens.
 

·
Registered
Joined
·
977 Posts
I live in La Paz Bolivia. I have other bikes (BMW S1000RR & R1100S) both work great, of course 30 years younger


Bolivia, You have just jerked me back to reality that the Internet has shrunk the world and we can communicate with folk half a world away in just a few seconds.



I would not think that the turbo would provide much boost in neutral, especially at idle, as I understand that the more load is on the engine, the hotter the volume of exhaust gasses, and the more the turbo spins. It's kinda like you get the most boost when you need it the most. I know that in aircraft the turbo is designed to provide sea level performance at altitude but your Honda may be designed somewhat differently. I would think it should perform similar to a naturally aspirated cx500 at sea level. Just my best guess. Billrod
 

·
Registered
Joined
·
220 Posts
Discussion Starter · #16 ·
Fuel injection seems OK. My plugs are not covered with soot. Waste gate is no stuck closed. But if it is stuck open then that could explain the

lack of boost. The engine is in pristine condition 18000KM. Purchased the bike in the US and had it shipped here. I have a Fuel Mixture meter I will hook it up to see what Lamda reads n get back.
 

·
Registered
Joined
·
254 Posts
The turbo won't provide any boost at idle and it will be difficult if not impossible to get it to create boost without any load. If it is creating ANY boost and isn't making a serious racket, I'd wager the turbo itself is OK. It's likely either altitude, (mine produces full boost at 9000 feet just fine, though obviously more laggy) a boost leak, or wastegate issue. If you say you can hear the turbo - that is a good indicator that a charge or intake pipe has popped off. I can't hear any substantial whine from any of my turbo vehicles unless I pop a coupler. Someone else with more CX experience can chime in here, but I only heard mine whine when I first got it and the intake tube was not connected at the compressor inlet.



I'm very interested to hear your AFR results. You have some sort of portable wideband o2? I was thinking of installing one on my CX just so I can see what's going on.
 

·
Registered
Joined
·
2,417 Posts
We did not ask the obvious question, have you checked your computer codes. If anything is out of sort, that is the first place to look. In an old thread someone had an altitude problem that seemed to clear under 10,000 feet.
 

·
Registered
Joined
·
147 Posts
Rique, One of our guys here in Oz had the same problem that you have.

Check that you have correctly installed the rubber tube joiner between the turbo-outlet long black steel tube and the inlet stub of the inlet manifold. If that joint is not properly sealed and the two spring clips are not fully holding the rubber joiner onto the relevant steel pipes, then you waste all the turbo outlet air-pressure/volume.

The inlet temperature sensor and the inlet pressure sensor can tell the ECU that it is at altitudes up to at least 10,000 feet, so don't think you're not getting proper mixture ratios.
 

·
Registered
Joined
·
101 Posts
bad spark plugs, boost leak, sticky springs, that can all effect not making the correct boost your looking for...



Start with the simple things like spark plugs, then if you need to look for pressure leaks, do a smoke test.



Also make sure all fasteners and clamps are really tight and maintained.
 
1 - 20 of 20 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top