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Slavvy posted:Sooo I've noticed that on factory bike ITB's, there is often vacuum lines that join all of the TB's together in a t-junction, then feed to a MAP. I don't have a MAP (working on it!), and each TB has two vacuum nipples adjacent to eachother, all of them are blocked off. I've noticed that my lovely off-idle stumble that I've been fighting for months (bike runs great in the rest of the range now that I've figured out what I'm doing!) is significantly reduced if I join all the TB's together with vacuum lines. So with that in mind: Dorman 5-way splitter like this maybe?
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Jan 6, 2019 04:22
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| # ? Apr 27, 2024 17:39 |
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Slavvy posted:Sooo I've noticed that on factory bike ITB's, there is often vacuum lines that join all of the TB's together in a t-junction, then feed to a MAP. I don't have a MAP (working on it!), and each TB has two vacuum nipples adjacent to eachother, all of them are blocked off. I've noticed that my lovely off-idle stumble that I've been fighting for months (bike runs great in the rest of the range now that I've figured out what I'm doing!) is significantly reduced if I join all the TB's together with vacuum lines. So with that in mind: It does seem logical to link them all together. My TB set has two ports per TB and, like you mentioned, has 4-into-1 into the MAP, and the other set blocked. I think your way is a good plan, since it lets all the various balancing arrangements happen automatically. Have you bench-synced your TBs?
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Jan 6, 2019 16:33
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I have, then I also tried vacuum syncing them but I suspect the short intake length gave me inaccurate results, seeing as joining them up improved the idle considerably. I've tracked down some fittings to join them all directly, when I've got a chance I'll pop the filters off and just check the balancing manually again in case I've made it worse trying to do it by vacuum. I've noticed heat soak + hot ambient air is going to be a problem with this thing. If I ride it I'm usually beating on it and the tune I've got now is pretty good for that, but the other day I went for a ride and swapped bikes with my slower, much less experienced friend. It was a very hot afternoon and he was riding slow and cautious, using the torque like a good boy. By the time I got it back off him it was chugging pretty hard and generally behaving like a bike running too rich for the conditions, it took a few brisk-but-relaxed laps around the block to cool it down to the optimal fuelling again. I figure an IAT is a good first step towards fixing this (obv closed loop would be better still but the cost difference is hundreds soo). How would I go about fitting an IAT with ITB's? Just drill a hole in the side of one of the center ones and screw it in? I've noticed on factory bikes they're always in the airbox and isolated from hot engine parts but I don't see any way to get around that in this case. I presume it would go on the filter side of the throttle plate?
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Jan 6, 2019 19:07
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IAT mystery deepens. I ended up trying to find whether the MS is set up to 'look' for one or if you can switch that feature off like you can for any number of other sensors. I am unable to find anything in tunerstudio or in the documentation that tells you this. The manual page about temp senders doesn't mention what to do if you haven't got an IAT, likewise the pinout only tells you how to wire the sensor, not what to do if it hasn't got one. I assume this is because the underlying assumption by the designer is that you can't not have one? It's also kind of a mystery why whoever built the bike didn't fit one, it seems like a pretty straightforward thing to do compared to some of the other stuff that's on there. So I had a look at what's actually on the bike, and it looks like pin 26 IAT goes to a 2-terminal connector, the other terminal appears to go to the sensor ground circuit and the two are just joined together. My concern is they're joined like this but the MS is still looking at that signal thinking it means something. I can see the noise in the IAT circuit and it matches noisy spikes in the other traces and I feel like I could get a much smoother idle and better running in general if I could disable it in a better way somehow.  You can see the random spikes in the MAT trace, the flat line values start around 18'c when the bike is cold and gradually go up, by the end of a half-hour ride it's about 26'c. I don't understand how this can be because there is literally nothing there, please help?
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Jan 7, 2019 20:48
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I gotta bump this thread to keep it out of the archives. I changed jobs, life got in the way, but I'm slowly banging away at the tiny bits of things. I would like to be done by the end of May, but the chances of that are small.
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Mar 6, 2019 08:45
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Well, I at least decided to go through and rationalise/tidy up my entire MS harness off the bike. That's when I noticed everything was earthed to the battery negative, whereas the MS manual stresses running the earths to the engine itself. So I changed everything around and after a few teething problems it all works. Except the lack of voltage drop means all my tuning is useless as it's based on faulty sensor signals and I'm back to a bike that barely runs, gotta make the VE table from scratch again.
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Mar 6, 2019 09:03
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I got a raise and another raise and now I have free time! It's almost the beginning of May and there's a nonzero chance I'll be done by the end of May!
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Apr 28, 2019 15:26
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| # ? Apr 27, 2024 17:39 |
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babyeatingpsychopath posted:I got a raise and another raise and now I have free time! It's almost the beginning of May and there's a nonzero chance I'll be done by the end of May! There's now a zero chance it'll be done by the end of May. All of my vehicles have died (including this stupid bike, again), and I'm desperately trying to find reliable daily transport. Of course, when I rebuild this block to fix the damage done, I'll be installing the EFI then.
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May 11, 2019 16:44
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