Plug chop test results...
- Thread starter Shuriken
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I think you may get an improvement in operation with 147.5 Mikuni mains.
Shuriken
Well-Known Member
Funny you mention that. I put 147.5s in my 85 many years ago....
I have some 147.5s on the way. It will be nice to have 152.5, 150, and 147.5 to experiment with.
Aquamax
Well-Known Member
To me, that's not a bad color. I think you may find the 150's will be golden to your altitude...especially with OE exhaust. Is it a single UNI filter in the stock air box? If you had a Kerker system, I would definitely say you need to get into the 147.5 range.
I agree. I'd be ok with the look of those plugs.
Mark
Mark
Shuriken
Well-Known Member
It is a single filter. I've used K&N before and have one of those in my 85. This UNI came installed in the bike.
I might be splitting hairs.... but my 85 feels slightly stronger. It has the same OEM configuration, but uses a single K&N with the OEM exhaust, and 147.5 main jets.
I have some 147.5s coming. I do need to remove the carbs one more time to replace the right rear carb body. The PO effed up the idle mix screw threads. I tapped out the body to m7x1 and made my own bolt, which works, but it looks hokey and isn't as easily adjustable. So I need to decide if I want to keep these 150s installed or try the leaner mains.
The difficulty is that I sometimes ride at lower elevation (around 2800) and sometimes ride at higher elevation (over 8500). But in the current state of tune, which looks and feels pretty decent, I have to have my mix screws out beyond 5 turns. I have not gone a step down on pilot fuel jets.
I really wish I could find my Colortune plug that I bought 20 years ago. They are like $200 now. I used it on my old XS1100s to really see what was going on. I use the "ear method" in general but the XS1100s preferred a slightly rich idle. For example, bunson blue flame at idle on my XS1100s just wouldn't quite hold the idle, while slight orange flame would; but it was real easy to get all 4 pretty close with the Colortune plug, combined with the ear method.
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Shuriken
Well-Known Member
Wow... thanks for that! I had never seen that thread before now. Super helpful.
It looks to me that there are some mentioning in that thread to go up on the pilot fuel and down on the mains.
If so, I can see why I have to go 5-7 turns out on the a/f screws...
Alright... unfortunately I am on the last dregs of riding and testing season but there is a ton of info in that thread and new tests for me to perform.
I think it's worth getting it right. I can't imagine what this engine would do, properly tuned at sea level.... I haven't really found a tire that will withstand a clutch drop in 1st though...
There was one guy here in Denver that had a stock Vmax, and did exactly what was prescribed.
Once it was done he had a lean, crisp perfect in every way Vmax, so much so that it made me want to return mine back to stock!
He got married in 2021 to an anti bike wife, sold the Max, got divorced this past June.....
Shuriken
Well-Known Member
Shuriken
Well-Known Member
Installed 42.5 fuel pilots. Mains are still 150 while waiting for others to show. Also waiting for small round 95 jets for pilot air.
Reassembled and tested and I think the idle and mid feel stronger. I don't hear any airbox burping or popping. I ran out of daylight so can't plug chop but maybe soon. It is quite fast through the gears and really rips from 6-9500.
Reassembled and tested and I think the idle and mid feel stronger. I don't hear any airbox burping or popping. I ran out of daylight so can't plug chop but maybe soon. It is quite fast through the gears and really rips from 6-9500.
Shuriken
Well-Known Member
Haven't had time to do a fine, fine tuning of idle mix or to do a proper plug chop at all circuits yet, but these indicate the mix as I idled the bike back into the garage after last night's ride. So this should be the idle mix condition.
I will try to test mid and full as well as mpg if I can hit the weather window in a couple hours.
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Shuriken
Well-Known Member
Had the last good weather day today and took advantage. The bike feels like it has enough to easily see 140 but I won't take it there.
Plug chop today looks about the same. I'll have to buy a new set of plugs to make sure but may be out of season, now.
Funny thing is the plugs look good but it smells rich. With hooligan riding style on first leg of the trip, I only saw 28mpg, but that was fast stuff.
Return leg was probably mostly 75mph and I saw 31.2mpg. This seems lower than I've seen on my 85... although it does have the 147.5 mains...
Plug chop today looks about the same. I'll have to buy a new set of plugs to make sure but may be out of season, now.
Funny thing is the plugs look good but it smells rich. With hooligan riding style on first leg of the trip, I only saw 28mpg, but that was fast stuff.
Return leg was probably mostly 75mph and I saw 31.2mpg. This seems lower than I've seen on my 85... although it does have the 147.5 mains...
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