Need help regarding the reliability/and problems of direct fuel injection

P

poster

Active Member
Hey guys,

I am planning to buy a used 2005 Suzuki C50 this Sunday. The seller says that he had a fuel related problem with the fuel injection system.

Apparently he was using 87 octane fuel from a (Wawa) gas station. After cleaning the injectors he used only 93 octane and there were no problems since then.

Okay so is there a possibility that the fuel injection system is f*cked up because he used the 87 oct gas?
He didn't mention for how long he has been using it on 87 oct gas so I have no idea to be honest of the severity of the problem. But he says that after he cleaned the injectors and started using 93 oct. He had no problems since then and it was a year a go that it happened.

the bike is pretty loaded up with all the accessories such as saddle bags, windshield, Cobra fuel management unit etc. Price is pretty good too. I am just worried that I might buy the motorcycle and end up needing to replace the fuel injection system.

**Is there a way to test the fuel injection system and see what condition it might be in?**

* Sorry I am still a novice to motorcycles as it is and I have only worked on carbs before. Direct fuel injection motorcycles are completely new to me.*
 
Octane should not effect anything in the fuel system. All gasoline grades (of the same brand) have the same detergents/additives so switching octane should have no effect on anything in the fuel system. Octane rating is simply resistance to auto-ignition. It is possible that on 87-octane he was pinging/knocking and this caused the bike to run like crap which he assumed was a problem with the fuel system. A C50 has a 9.4:1 compression ratio which theoretically should work with 87 octane but personally, I run premium in all my bikes.

The Cobra fuel management system raises a red flag with me, not because I know anything about the product but because it's monitoring all these parameters to make it's corrections and there's no way to know if the installation was of good quality. People can't get electrical tachs to work right half the time, how can we be sure the Cobra is reading the RPMs right (and etc.) if it was installed by an amatuer? If the bike starts having issues after you buy it, the first trouble shooting step I would take is to remove the Cobra fuel management and see if there's a change.
 
jwarriner said:
Octane should not effect anything in the fuel system. All gasoline grades (of the same brand) have the same detergents/additives so switching octane should have no effect on anything in the fuel system. Octane rating is simply resistance to auto-ignition. It is possible that on 87-octane he was pinging/knocking and this caused the bike to run like crap which he assumed was a problem with the fuel system. A C50 has a 9.4:1 compression ratio which theoretically should work with 87 octane but personally, I run premium in all my bikes.

The Cobra fuel management system raises a red flag with me, not because I know anything about the product but because it's monitoring all these parameters to make it's corrections and there's no way to know if the installation was of good quality. People can't get electrical tachs to work right half the time, how can we be sure the Cobra is reading the RPMs right (and etc.) if it was installed by an amatuer? If the bike starts having issues after you buy it, the first trouble shooting step I would take is to remove the Cobra fuel management and see if there's a change.
Click to expand...

You raised a very good point. I haven't even thought about the Cobra unit. Now I am starting to have second thoughts about the bike. Now the price while on the low end that these bikes go for starts to make more sense. He could easily sell the bike for more considering all the accessories that he has on it.

hmm... is there a way to test it? I am going to test ride it so is there anything that I should look out for that could be caused by the crappy installation of the cobra unit and or faulty fuel injection system?

- backfiring? pops?
- what else can I look for?

My last bike that I bought for cheaper had heaps of problems that showed up down the road. Spent way too much money and time fixing all of it. Now I just wanna buy a bike and ride it rather than tinker with it all the time.
 
Injectors will be fine and can be cleaned quite cheaply. A bigger issue would be the COBRA system, but if it has operated OK for the last year then it's probably OK. If it were me, I'd agree to the sale subject to an inspection at a local Suzuki dealer with a dyno - which I'd offer to pay for. Get them to give it a once over on the dyno and see if the EFI system is working OK.

It's hard to hurt them but my son added a PC3 to his BMW and it screwed up so much in the electronics that it cost him thopusands to fix. Isolated incident probably.

Get teh bike checked out and then you will have peace of mind and perhaps a cheap bike
 
93 octane is a bit extreme for a bike with a fairly standard compression ratio. I highly doubt 87 was your problem. Might want to halve the difference and use the medium grade. To high of octane won't detonate completely. You'll be wasting money and getting shitty mileage.
 
teazer said:
Injectors will be fine and can be cleaned quite cheaply. A bigger issue would be the COBRA system, but if it has operated OK for the last year then it's probably OK. If it were me, I'd agree to the sale subject to an inspection at a local Suzuki dealer with a dyno - which I'd offer to pay for. Get them to give it a once over on the dyno and see if the EFI system is working OK.

It's hard to hurt them but my son added a PC3 to his BMW and it screwed up so much in the electronics that it cost him thopusands to fix. Isolated incident probably.

Get teh bike checked out and then you will have peace of mind and perhaps a cheap bike
Click to expand...

I will see how much such inspection by the dealer would cost. The bike's price is pretty good and definitely on the lower end but if the inspection is going to be too costly i won't see the point in doing it. I might as well spend more money and get myself a bike with a truer market price and worry less that something is wrong with it.

I will go test ride it and see if anything stands out in the performance of the bike.
 
I think you're overeacting when you question the reliability or problems related to fuel injection. It's a far better setup than carbs will ever be. Reliability, power, performance all better and very, very few problems! I'm not a carb hater but yes, it's almost 2012. Even NASCRAP is going to fuel injection in 2012. Poor 4bbl Holleys! Lol!
 
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