450 09 engine starting, but cutting out (unstable idle) + glowing exhaust

[speeddemon]

First problem: when i start, it runs fine for a few seconds, but then engine revs go to low and the engine dies. After that it can sometimes be a pain in the # to start again even with full throttle method. I can work around the problem by keeping the engine running by using the throttle but if i let go the first 20-30 seconds the bike sometimes coughs and dies. After a minute it idles better.
If i start and ride it and play with the throttle (not below 2000rpm) the bike behaves normal and runs strong as ever.

Second problem: it tends to run so hot when idling that the exhaust header begins to tun red shortly followed by coolant loss.

BTW the valve clearances were checked 10 riding hours ago, head gasket + piston ring replaced 10 hours ago, yesterday i have installed a new spark plug + cleaned the air filter.

Anybody got ideas what causes these problems?
Thanks in advance

[Qui-gon]

That model should have the Kokosan fuel injection system if it's efi or carb if not. Can you verify that?

[speeddemon]

I can verify that my bike has efi (FSR 450 engine)

[Qui-gon]

which type? Marelli or Kokosan? Should be Kokosan for that year but with Gas Gas's QA you never know?

[McGuiver]

More than likely, you have a partially plugged injector. I just went through this with my 05. Same exact symptoms.......do not attempt to clean injector, unless you know a reputable bike shop that can do it right. I had to replace mine at the tune of 300.00 ouch! When doing so, also replace your fuel line, and install a good fuel filter in-line just before the injector. This is all caused by the ethanol fuel eating the rubber fuel line, and depositing small chunks of rubber in your injector! Do yourself a favor, and stop using fuel with ethanol.......it will save you lots of headaches!! There are other posts on this here as well. Good luck!

[Qui-gon]

Assuming that it is a Marelli sytem............

That injector is $10 in china in lots of 10 upwards.There is an fuel filter in the top of the injector which will catch the debris from the rotted fuel line. The goo that is left in there can be easily cleaned out of the injector with standard carburetor cleaner. Stand the injector nozzle down in it and leave it for an hour. Keep filling the inlet side up top the top (it evaporates) and occasionally flush it using the pressure from the carb cleaner aerosol. Protect your eyes from the back spray! Takes about an hour to do.
If you put another filter in that pressure line make sure you get a high pressure type and the same with the hoses. It shouldn't be needed anyway if the hoses are new and ethanol proof as there is a gauze filter in the tank and one in the injector!
Of course it may not even be this...
Check the hose inside the tank where the pump connects to the pressure system and also check to see what the fuel load is set at. I have had 1 ecu here where the fuel load on the "good" map had reverted to the setting for the EPA map. It was set at -40 which made it run like crap and the exhaust glow a nice cherry red!

[speeddemon]

I think my bike has Kokusan efi since it's a 2009 model with the same engine as the ec450. I don't tank bio ethanol fuel and it's hard to get here in belgium, i usally go at shell, esso or texaco, i alwayse use octane 98.

[McGuiver]

I tried cleaning mine, but was unsuccesful......that's why I suggested getting a new one. Someone said there was a process where-by they could be cleaned with a special machine at some dealerships?? Don't know......but got a new one and never looked back. Obviously you want high pressure lines etc. when replacing, but do put them in. Once that ethanol shit starts eating the rubber, it has been compramized, and will forever be a problem! If you can get $10.00 injectors, please share this info with us, as I could not find a supplier for them. I'm sure it's possible........just not common knowledge! I would buy a couple at that price, just for spares!

[Qui-gon]

There is a thread started by you on injector cross reference in this section. The injector you want is an IWP043 originally made by Weber and now made just about everywhere in China. If you do a search on that number it fills your screen with literally hundreds of Chinese sites claiming to have these in stock. I also found out about the gauze filter from one of those sites. They had a sectional diagram of the injector which is useful. It's not easy to spot the filter unless you know it's there. Here's the link to the page with the diagram:
http://www.alibaba.com/product-gs/46...or_iwp043.html
Price there is $9.5 to $15 each min order 500 but there are hundreds of other sites no doubt some of which are bogus.
I also recall seeing them from a US supplier for about $60 which is not unreasonable compared to OEM. The injector is also more common in europe as it was fitted to a few Fiat cars.
Hope that helps?

[McGuiver]

Thanks! Most helpful indeed! I wish I had seen your post from earlier in the thread that I started originally! By googleing that part number, I was able to find a weber injector for very little money!