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Post by 90GTVert on Jan 19, 2016 7:13:01 GMT -6
I'm guessing what you saw were fuel vapors. Hopefully anyway. True smoke wouldn't be good to be coming out of the intake. I'm with JR on this and say your best bet is to wait on that new intake. One of the first rules of troubleshooting IMO should be to take care of known problems.
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Post by 90GTVert on Jan 18, 2016 8:22:38 GMT -6
It's normal to see an air pocket in high spots along the fuel path. If you're suspicious of fuel flow you can remove the line from the carb or outlet side of the shutoff valve and let it drain into a container. You can even loosen the bowl drain and test right from the bowl if you'd like. I've done mine before by watching a timer so it flows for exactly a minute, then measuring the fuel when I was really suspicious of the fuel getting to my carb. Just did this last week actually. With 3/16" fuel lines I was getting 160ml per minute with straight down fuel hose routing. With it routed the best I could seem to get it (because I have a similar issue where the location of the petcock outlet makes it go mildly uphill at first) I got 140ml/min. Checked with the fuel cap off, same. I checked from the drain as well and got very close to the 140ml/min. Not really necessary, but if you can't tell that it's enough by watching it or find that sort of thing interesting it's an option.
Surging idle could be a sign of a vacuum leak. You may want to double check that you haven't created any while rearranging your vacuum setup. A lean idle would also be likely to cause RPM to hang at least slightly if you rev a little then let off. If you indeed had a fuel supply issue that is cured now, readjustment of the mixture screw may be required. Fuel vapor could be getting into the vacuum hose to create moisture. It's not old fuel is it? Air filter clean? Any backstory we need to know, like the scooter sat for a long time or has never ran well since you owned it etc...?
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Post by 90GTVert on Jan 17, 2016 8:59:59 GMT -6
Do your best to create a steady downhill routing of the fuel hose and you may improve flow. Personally, I ditch the vacuum petcocks. I hate them. They're way too prone to failure. I just replaced one on my 150 a few days ago because it was very slow filling the lines. If you measure the threads on your tank/petcock, sometimes you can find a manual shutoff that threads on. Mine was M16x1.5, but there are 14mm and probably others. I found it on eBay for $6 shipped. You can get them without the reserve function too. I don't really have a use for reserve, but it was $3-4 more for the plain ON/OFF version.   I don't know that the replacement is necessary here, because it runs above idle where it should demand more fuel. You can try a couple of simple things to see if fuel is playing a role in your starting difficulties. Cover the inlet of the airbox with your hand or partially cover it. That will restrict airflow and enrich the mixture. If it fires up and idles well doing that, you can be pretty sure you need to keep investigating fuel delivery. You can also disconnect the airbox and see if it starts that way. That leans it out and if it does better that way, you're getting too much fuel. You can look at the spark plug after you try to start it as well to see if it's wet or dry. If it's soaked you know you have fuel and possibly too much. If it's totally dry, you aren't getting fuel. I think I'm seeing an aftermarket CDI, a blue one, mounted to the scoot. I can't really tell. If so, try putting the stock CDI on. I don't really think that is your problem. The reason I'm suggesting it is that it may help until you get it sorted out. Many aftermarket CDIs have a flat timing "curve", so they will advance the timing even at starting and idle speeds. This can make even a scooter in good working order harder to start. |
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Post by 90GTVert on Mar 14, 2015 13:25:40 GMT -6
Most of the good pipes will be similar in price to the LV or more, but you can keep an eye on eBay or if there are many scoots in your area maybe craigslist for a used pipe. The ZX or ZX-R is good for most street and sport builds. The SP3 or GP won't make as much power at higher revs as the ZX, but they're a bit more stealthy.
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Post by 90GTVert on Mar 14, 2015 11:32:39 GMT -6
IMO the CDI and air filter will be a waste of your time and money. It's always a good idea to get the carb and CVT in tune, and I like using sliders instead of rollers in the variator. The Zumas I've been around were in a good state of tune in stock form though, so I'm not sure that you'll get much for your efforts with just jetting and swapping weights or springs. If you plan to do other mods, you'd prob be better off waiting to tune it until then.
Your biggest gains in power will come from a tuned pipe and/or a big bore kit. The Zuma also has very deep final drive transmission gears, so to see high speeds you will probably need to do a gear swap.
If you stick with the stock oil injection system, most big name 2T oils intended for injection will work. Preferably synthetic or semi-synthetic.
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Post by 90GTVert on Feb 19, 2015 8:50:53 GMT -6
Did you make sure the main jet was clear/clean when you cleaned the carburetor? If the air box is off it will most likely need a larger main jet. You need a filter of some sort for street riding anyway, so I'd work on getting it to run with the air box installed. Check the air box out and make sure it's clean and has no cracks or missing screws or other damage.
It wouldn't be a bad idea to check out the automatic enricher.
Have you checked compression?
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