Suzuki SV650 Riders Forum banner

1 - 1 of 1 Posts

·
Registered
Joined
·
748 Posts
Discussion Starter #1
For those of you who may have been following the progress of the Bandit 400 I got for my girlfriend, I've got an update. The bike has been at the shop for about 3 weeks now while they worked on some of the issues. For a quick recap, the major issues were:

#1 Bike would stall or idle very low after riding for a mile or two (or more) and then coming to a stop. You would pull up to a stop sign or light and the engine would idle very low or would just quit altogether. It would start right up again, but it's annoying and kinda dangerous depending where you are.

#2 You could not go over 65-70 mph on it. Once you reached that speed the bike would go no further, like it was running out of gas.

#3 I noticed that the valves might need to be adjusted as I could put a dollar bill by the exhaust outlet on the muffler and it would suck it in on certain firings. This is usually an indicator that at least one or more exhaust valves aren't sealing all the way and may need to be adjusted (or worse).

-btw, I think I'm right about this theory with the dollar bill, someone feel free to correct me if I'm assuming incorrectly about the cause & effect here-

So after doing several things we knew needed to be done; replaced the coils, plugs, plug wires, air filter and these problems were still present, I felt it time to take it to a friend who is the service mgr at one of our local dealers (nice to have friends :) ) Here is what has happened.

I was correct about the valves. He said they were quite a bit out of whack but they were still adjustable and undamaged. He said compression is very good across all cylinders now.

They tore down the carbs and while they were pretty clean, they were missing a few internal bits like o-ring/seals & such. He didn't tell me all the details on the phone but did let me know that he had all the needed parts on hand and has taken care of it. Between that and the float adjustment, it look like the dying at a stop has been taken care of. he said it was still dropping its idle just a bit, but they weren't done looking at that yet. I'm not worried really if the idle drops a couple of hundred or so as long as it quits dying :)

Now issue #2 with the bike giving out is still a bit of a mystery but I think I may have a solution. Here's a bit more on this and I'm hoping to get some opinions here on this possible cause. I first thought when I encountered this problem that it wasn't so much speed related as it was rev related. I'd get the bike out get to about 65-70 mph which was equal to around 8000 rpm. Once I got there I could give it all the gas I wanted but it would go no further. I though "well maybe its valves, carbs, etc" and was going to be addressing these issues so I wasn't worried to much at that time. After I had done some work on it I found it still hit a wall at 8000. So I take it out again and see how fast it would go in 5th and sure enough, the engine rev'd higher, but I found myself stuck at around 70 (just little faster than in 6th). My thought was I was running out of power due to some of the issues mentioned earlier. It would rev up just fine in neutral to any point on the rev range so I felt it happened only under a load.
Now its been three weeks and they've been able to overcome all issues except the 70mph limit. I talked to him last week and he mentioned that they still couldn't figure out why it wouldn't rev higher in 5th and 6th, but it would in all other gears and that they couldn't find anything wrong with ecu/cdi. They said they wanted more time to look at it and I toldhim go ahead. Now this got me thinking. "Just 5th and 6th gear?" Sound like a restricted bike from another market. I know that the ecu/cdi boxes for these bikes are hard to find and maybe somewhere down the road, someone got a replacement ecu off ebay or someplace like that, and it came out of a restricted bike. This to me would explain why it hits that wall at 70mph and yet nothing seems wrong with it, because technically there isn't. It's working as designed. Either way, I think a solution is near.

Best solution: since the ECU is no longer available from Suzuki, order a replacement unit from Carmo electronics. They build new ECU's out of new parts and one would cost about 350.00 or so depending on the Euro that day.

Possible workaround: Fool the Gear position sensor into thinking the bike is in 4th or any other gear that is not 5th or 6th.

I like the latter as it is much cheaper, but has on potential drawback. I think one could fool the Sensor by measuring the resistance of each gear position from the wire. Then placing a resistor on the wire for the correct resistance to make the ecu think it is in 4th all the time, and then just attach the wire to a ground point somewhere on the frame/engine. Seems like I read about someone doing something like this on a restricted Bandit 1200 overseas. However, my concern is that the neutral light will no longer function (bad). Is there another approach that would work and maintain the neutral light?
I would think something similar to the TRE's we have here on the board would work. I have one of the latest aTRE's installed on my SV and doesn't this fool the bike's gear position sensor (or more properly the ecu) into thinking its in a gear different than actual?

If so, could the TRE makers here on the forum chime in? Would it be possible for you guys to make something like the SV TRE for the bandit if i could give you the info you need?

Ok, I know, long thread and you've really stuck it out reading the whole thing. So for your efforts, here is a picture of a bunny with a pancake on its head.
 
1 - 1 of 1 Posts
Top