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Yosh Box/PC III Question

2801 Views 11 Replies 7 Participants Last post by  Viceroy
I have a DL1000K5 that has had the typically discussed FI problems at lower RPMs. I am the second owner of the bike which just turned over 5000 miles. The first owner had installed a PC III on the bike which never seemed to solve the running issues. When I took the bike to a local Suzuki dealer to discuss what they might do to help with the problem, I was told about tuning using a Yosh box. They told me I should disconnect the PC prior to doing the Yosh procedure, which I did. The bike now runs very well except for some sputtering/stalling out while at idle. Although the engine runs without hesitation above idle, my fuel mileage has suffered a lot. Before the Yosh tuning, I was getting 39-42 mpg, however, I now get 28-30. Can anyone tell me if this is normal and if it can be retuned using the Yosh to still run smoothly without the drastic reduction in fuel mileage? The bike has stock pipes and air filter. I guess my other option is to reconnect the PC and have a custom map done at a tuning center. I'd like to know what sort of fuel mileage others get and would really appreciate any suggestions on fixing this problem. :confused:
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Thanks for the response, PMC. I ride mostly back roads in rural Maryland with a little highway and town mixed in. I'm at a loss as to what might be going on with my bike. The air filter is like new and wouldn't be the problem. I talked to the dealer that did the Yosh tuning on it and he said they could try to do more adjustments but it's not even close to doing a custom map at a PC Dyno center. The PC tuner I talked to yesterday told me it would run $300 for a custom PC map. I'll keep that as an option but would love to find a cheaper yet effective fix. Maybe a second try with the Yosh would be the way to go. Also, I've wondered about the throttle bodies, but don't know if the problem could at all be related to TB adjustment. Any thoughts?
Thanks for the inputs. I haven't done anything with the secondaries, TB's or TPS. Since the bike just turned over 5000 miles and has had no other issues, I wasn't thinking these would be problem areas. When I first got the bike (with the PC already installed by previous owner) it still had rough FI issues. I tried downloading several maps found on the forum and had no luck in resolving the problem. I took the bike to a tuning center for PC's and had no luck there either. Problem was the center worked mostly on Harleys and they really didn't do me any good. That is when I went to a local Suzuki dealer and discussed the problem. They suggested disconnecting the PC and trying the Yosh box tuning. I'll have to say it took care of the hesitation issues, but the fuel mileage took a big hit. Bike has lots of power and is very smooth but drinks the gas. Sounds like SpringheelJack has had issues with the PC as well. Did you have a custom map or download some you found online? I'd also be interested to get some feedback from you, grantizzle, after your custom map is done. If you have good success and gas mileage doesn't suffer, that might help me decide to go for a custom map as well. I read a lot about PC success, but so far I haven't found it.
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Thanks for all the good suggestions. I know that tuning the FI to a richer setting will no doubt lower the fuel mileage, but what I see in the 28-30 range seems a bit extreme. The dealer that did the Yosh tune for me admitted that they have very little experience with it, so I'm wondering if the entire rpm range was tuned richer and causing the problem. I think if I could find someone who knows what they're doing, it would make a difference. I've called a few Suzuki shops in my area and none of them do Yosh tuning except for the one I used. Can anyone suggest a shop in the Baltimore area that might know what they're doing on this issue? Right now, I plan to take it back to have it adjusted to stock settings. Will probably do it next week. I've also read a bit about the Teka box that is similar to a Yosh. Anyone have experience with this one? Seems like the dealers around here don't have much experience with Vee FI adjustment issues other than suggesting a Power Commander.
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