My CF Moto runs like crap!

[datamancer]

Hi folks, I had hoped you could help me get my CF Moto Fashion running well. I bought the bike off of craigslist really cheap for a project scooter, but can't get it to run well for the life of me. BTW it's a 2006.

Here's what it's doing: First off, it won't idle, even if I turn the idle adjuster to the point where the spring won't let it go any further. When I first got it, it didn't idle, but had decent power when I revved it. Now after simplifying the vacuum system, it won't idle AND it has no power when I rev it. The engine cuts out and stumbles at mid and wide-open throttle.

Here's what I've done: I'm turning the bike into a naked chopper-style scooter, so I stripped off all the plastics for starters, I had to disconnect some electrical stuff in the front. I have most of it all hooked up again, but there are a few connections where multiple plugs can go into the same plug, and a few loose barrel plug connectors. I mention this to address the fact that there could be an electrical issue. No major electrical issues just out at me at the moment though, except that the backlight on my gauge is out. I was able to trace out most of what I needed to hook up my new headlight and turn signals, etc. and everything seems to work.

I have completely disassembled and cleaned the carb, which it hardly need because it was spotless.

I thought it sounded like a vacuum issue, so in the process of troubleshooting, I removed all the CA-compliant BS off the vacuum system, so now I only have about 3 vacuum connections, all new hoses. Someone had put a little cone-style air intake on the carb, but had left removed the tube which bends back to the airbox, but left all of the other airbox stuff attached to the bike. I removed all that as well so now the valve cover vent and crankcase vent are just open to the air.

The bike behaves as though it's running really rich, leaving black carbon deposits in the carb and puffing a little bit of black smoke out the exhaust. The weird thing is, no matter what I do to the carb, I seem to get no response from the engine. I can put the pilot needle in 0 turns, 3 turns, 5 turns, or 7 and it runs exactly the same. I changed the stock main jet from a 108-110 to a 118, still no change. I tested the bystarter and it seems to work fine, gets hot, piston expands, etc. I bought another one just to try it out but the one I bought is a little different than the one that's on there and the retainer bracket doesn't really fit. I kind of wedged it in there flush and held it in place while the engine was running though and it still doesn't seem to make any difference.

Any ideas? I'm pulling my hair out over here and am running out of things to try.

Thanks,
-Doc

[redhouse7]

In reading you post first I was thinking the carb needs cleaning, but if we assume it is as clean as you said that shouldn't be a problem. Second I was thinking vacuum leak, but it seems as though you took care of that except for the following statement...

so now the valve cover vent and crankcase vent are just open to the air

I'm wondering if this is you issue. I know on other engines if you remove the venting hoses they won't run well because by opening them up you can loose vacuum. Essentially you are opening a closed loop system thereby upsetting the balance in the motor. Other engine run fine with these disconnected. I know you can't completely restrict these ports, but perhaps some amount of restriction is necessary to make the motor happy.

The other thought I had was a leak between the carburetor and the motor, or perhaps a leaking head gasket. Perhaps a cheap vacuum tester is in order?

Anyway, good luck.

[datamancer]

Thanks for the input. I wondered that myself, but when I put my finger over the valve breather, it seems to be creating little puffs of air, not sucking in vacuum, so I figured it was ok. I tried capping it for a while, but the motor didn't behave any differently. The crankcase breather shouldn't matter, I don't think (I don't know much about this particular engine though so I could be wrong), because I see a lot of people will run their scooters with the covers completely removed.

I inspected the intake boot very thoroughly too, so even though I know that's a very common problem with these scooters, I don't think that's the issue, either.

The only thing I haven't done yet is adjust the valves or pull the top-end apart but the problem I was having seemed more fuel and carb-related, so I figured that I would focus on that first.

I'm worried it might be something broken in the top-end. Oh well, maybe that could be a blessing in disguise. If something was wrong with the piston or cylinder, I'd probably just buy one of those 300cc kits. I got such a good price on the scooter that it would probably be worth the cost of the upgrade.

-Doc

[zfjelstad]

Did you change the fuel filter? I was experiencing the same symptoms and changing the fuel filter definitely helped my situation. Did you adjust the main carb needle to a leaner setting? This also helped. I have my needle at the leanest setting and mixture screw tightened all the way (however I think my fuel enricher may be bad) and it runs good now. The fuel enricher may also be an issue.

[datamancer]

Thanks for the idea. I have a new Mikuni fuel pump on the way, so I figured I'd change out the in-line filter when it gets here in a day or two. The scooter had decent power at first, but it's possible when I drained the fuel and put in fresh gas in it, I kicked up some junk in the tank which eventually clogged up the filter.

-D

[cpete1]

Pull the belt cover and check your clutch. (the driven pulley) These things need to be disassembled and lubed ,I'm guessing at least every 5 thousand miles. If the clutch is "grabbing" the motor won't be able to idle without "load". I went through all this as I didn't lube the clutch, eventually started eating belts at 150 miles. Beyond that, go back to basics and check that the fuel pump is working, use wd-40 or ether and mist around the carb base and look for vacuum leaks. Revs will ride if the spray can get into the system. Keep us informed, we'll keep thinking. Good Luck
Chris

[datamancer]

Thanks. That's one thing I haven't tried yet. I'd imagine that problem would go away at WOT, but I could have multiple issues going on here at the same time, One causing bad idle, and another causing fuel starvation at WOT.

[oldbikerider]

"The bike behaves as though it's running really rich, leaving black carbon deposits in the carb and puffing a little bit of black smoke out the exhaust. The weird thing is, no matter what I do to the carb, I seem to get no response from the engine. I can put the pilot needle in 0 turns, 3 turns, 5 turns, or 7 and it runs exactly the same. I changed the stock main jet from a 108-110 to a 118, still no change."


The way I read your description, it almost sounds like the float or float needle is hung up and dumping fuel.

[WarrenS]

Check your pilot jet. It may be loose or missing. When you open the float bowl it is the one off to the side. The main jet is in the middle.

[datamancer]

Oct 23, 2012 3:37:10 GMT -5 oldbikerider said:

The way I read your description, it almost sounds like the float or float needle is hung up and dumping fuel.

That's what I thought, too, but I just took the carb apart again the other day and triple-checked everything, blasted everything with carb cleaner, removed everything I could on the top and bottom of the carb, stuck a can of compressed air into every opening, checked the jets, etc. and it all looks perfect. The rubber on the float needle looks brand new, and the needle slides in the channel smoothly and the float seems to be in good condition.

[datamancer]

Oct 23, 2012 8:36:10 GMT -5 WarrenS said:

Check your pilot jet. It may be loose or missing. When you open the float bowl it is the one off to the side. The main jet is in the middle.

Both of the jets are there, the tall main jet holder with the tiny main jet screwed into the top, and the small slow jet sitting down in the hole.

Is it possible to switch them accidentally? Are the threads the same? I've just been following the way it was put together when I found it, but it's possible the previous owner swapped them.

[oldbikerider]

So the float needle is good and clean, It still sounds like a fuel problem.I have found that sometimes the float tang ( where the float needle rides) needs bending to get the fuel level right. The carb needs to have just the right amount, it floods if it never closes, or it starves at high rpm if closes too early. It sounds like it is not closing when the bowl is full. Does any fuel get into the air cleaner? If so look at the tang.
When I pull a carb off, I attach a hose to the fuel inlet and with the bowl off, I blow through the hose and operate the float to see where the shut off point is. Cheesy, but it has worked for me when I don't have the spec for the float height.

[datamancer]

The way my float is set up now is that the needle moves with the float, until it gets to the top, then the needle seems to bottom out, but the float still has a few degrees of movement above that point, and lifts off the needle clip. That sound about right?

I'll have to try the air flow trick to verify everything is working properly. Thanks for the tip.

[datamancer]

Oct 22, 2012 7:43:33 GMT -5 cpete1 said:

Pull the belt cover and check your clutch. (the driven pulley) These things need to be disassembled and lubed ,I'm guessing at least every 5 thousand miles. If the clutch is "grabbing" the motor won't be able to idle without "load". I went through all this as I didn't lube the clutch, eventually started eating belts at 150 miles. Beyond that, go back to basics and check that the fuel pump is working, use wd-40 or ether and mist around the carb base and look for vacuum leaks. Revs will ride if the spray can get into the system. Keep us informed, we'll keep thinking. Good Luck
Chris

Im no expert with CVTs but I took the cover off today and checked everything out. It all *looked* ok to me. I could turn the clutch very easily with my finger in the holes like an old rotary phone and spin the wheel forward and backward. The belt looked really good and while I was in there, I drained the gearbox oil and refilled it with some fresh oil. I didn't pull anything apart any further though. I'll need to do a little research about the clutch first before I get into it, but I'll probably change out the rollers eventually.

-Doc

[datamancer]

Ok, problem solved...hopefully. I had a friend take a look at it and with a set of fresh eyes on the project, he noticed that the previous owner apparently drilled out the #38 slow jet to OVER 1/16TH OF AN INCH!! That explains why it was dumping fuel into the carb like crazy.

I ordered a #40 jet today and I'll probably run the #118 main jet along with it because I have a K&N filter directly on the carb.

Hopefully this should make it purr like a kitten.

Thanks for all your help. I really appreciate it.

-Doc

[datamancer]

Quick update- My new jets came in the mail and the scooter works wonderfully! I'm running a 115 main and a 40 slow jet with a the K&N filter. I just need to play with the pilot screw a little bit and maybe tweak it another 1/4 turn and I think I'll be perfect.
This thing moves! If I'm feeling brave and foolish, maybe I'll take it out on the freeway and see what it can do, but I'm confident I can break 65 on it the way it is. I'm curious to see if I'll get more top speed from removing all the plastics and shaving the extra weight off, or less top speed because I've killed all the aerodynamics.
Time will tell.

[datamancer]

Still some work to do, but here's the basic configuration. There's another plastic cover I need to modify and reinstall in front near the pegs, then I need to neaten-up my wiring and I think I'll be done.

-~D~-

Attachments:

[cpete1]

Congrats on solving your problem. Definately a "different " look you got there. Curious as to how the milage and performance has been affected by your body loss.
Chris

[rerun2]

Just a wild thought, but I imagine that the removal of the plasics even though you shed some weight the added drag of all those 'dirty' surfaces will actually hinder the top end... the Helix is a pretty aero dynamic machine I think.

[oldbikerider]

Glad you got it solved, prior owners can do some odd things to a bike.