Post by zambia on Jun 26, 2014 13:19:19 GMT -5
OK, I’m back needing some help with my H2 tuning. For the most part I could not be happier with how the bike runs - tons of low end power and smooth delivery up deep into red line. I have also been getting excellent mileage - not important, but maybe a sign of decent running? This (ported with 38mm rounds) bike gets better fuel mileage than the stock version.
Anyway, at Paris a very knowledgeable racer took the bike out for a blast. He loved the bike but warned me of detonation he could hear at WFO. I have the bike WFO a lot but have never heard a single ping…which is most likely due to an untrained ear for such things - all I hear is the brake lever rattling, and the pipes singing. So I was warned that the bike could seize or hole a piston and the quick fix might be bigger mains.
Yesterday I put in bigger mains (went from 190 to 200)…now the bike runs like crap! Up top it seems fine, but the low throttle positions and idle are awful. Idle is going up to 3K (lean?) and the 1/4 throttle is super rich. It used to 4 stroke very mildly at 3,000 RPM under no load, but now it’s terrible.
I need suggestions for what’s my next step. I also can’t understand why the idle is lean now - I thought maybe there was an air leak after re-installing the carbs, but I tried in vain to find evidence of that (propane around the intakes etc.)
Maybe I should just go back to the 190’s and adjust the timing? I double-checked the timing before Paris and got it as good as I can…the plugs look about perfect to my eye (the only possible hint of lean might be a tiny hairline ring of grey around the circumference of the electrode tip - so small I can’t tell even with a loupe whether it is grey or just bare metal) the insulator is light brown almost from top to bottom, and the strap is light brown too.
Right now I have had to turn in the air screw from 1 1/2 out, to 3/4 turns out, just to keep the idle low. Pilots are 40’s - knowledgeable guy asked me what needle jets I’m running but I have…no idea.
Thanks for any help/suggestions.
Z
p.s. one other weird question while I have your attention - after setting static timing with a dial gauge on all 3 cylinders, I put the timing light on and wicked it up to 4K…the left and centre cylinder, the pointer was bang on and never flinched. On the right cylinder, the pointer was behind at idle, but as revs increased you could see the advance right up to 4K at which point the marks did align (after a slight move of the pick up). Is this common? Why would the advance be so visual on only one cylinder? Could that indicate that I goofed on the static timing?
Anyway, at Paris a very knowledgeable racer took the bike out for a blast. He loved the bike but warned me of detonation he could hear at WFO. I have the bike WFO a lot but have never heard a single ping…which is most likely due to an untrained ear for such things - all I hear is the brake lever rattling, and the pipes singing. So I was warned that the bike could seize or hole a piston and the quick fix might be bigger mains.
Yesterday I put in bigger mains (went from 190 to 200)…now the bike runs like crap! Up top it seems fine, but the low throttle positions and idle are awful. Idle is going up to 3K (lean?) and the 1/4 throttle is super rich. It used to 4 stroke very mildly at 3,000 RPM under no load, but now it’s terrible.
I need suggestions for what’s my next step. I also can’t understand why the idle is lean now - I thought maybe there was an air leak after re-installing the carbs, but I tried in vain to find evidence of that (propane around the intakes etc.)
Maybe I should just go back to the 190’s and adjust the timing? I double-checked the timing before Paris and got it as good as I can…the plugs look about perfect to my eye (the only possible hint of lean might be a tiny hairline ring of grey around the circumference of the electrode tip - so small I can’t tell even with a loupe whether it is grey or just bare metal) the insulator is light brown almost from top to bottom, and the strap is light brown too.
Right now I have had to turn in the air screw from 1 1/2 out, to 3/4 turns out, just to keep the idle low. Pilots are 40’s - knowledgeable guy asked me what needle jets I’m running but I have…no idea.
Thanks for any help/suggestions.
Z
p.s. one other weird question while I have your attention - after setting static timing with a dial gauge on all 3 cylinders, I put the timing light on and wicked it up to 4K…the left and centre cylinder, the pointer was bang on and never flinched. On the right cylinder, the pointer was behind at idle, but as revs increased you could see the advance right up to 4K at which point the marks did align (after a slight move of the pick up). Is this common? Why would the advance be so visual on only one cylinder? Could that indicate that I goofed on the static timing?
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