What plug do you run?
Finally got the Mack Mag built!
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FurryOnTheInside
In Memoriam
NGK BPR6HIX with NGK non resistor boot, in an MZ Miami "R" head.
bike4life
Well-Known Member
This thread might help w/ your caliper problem as it’s not clearing the sprocket. It’s cheaper than buying a new one that is small and fits.
https://motoredbikes.com/threads/rear-brake.53018/
https://motoredbikes.com/threads/rear-brake.53018/
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Ok I officially found the source of my current issue! I don’t know at what point my bike is doing it but, I ran the bike yesterday without the air filter and my rpms were in the 9,000’s at WOT after the engine warmed up. The bike ran better than it ever has from idle to the top end. I bought a new massive air filter in hopes to solve the issue of the engine 4 stroking from not enough air getting into the filter. I put the new uni filter on and very very lightly oiled it per the instructions. Started the bike up and ran it down the road and all seemed good and well until after about a mile of all rpm ranges. It started to four stroke and bog upon throttle and my WOT rpm was topping out at about 6600’s rpm. I realized my engine is spitting gas back through the carb into the filter. So much so that it soaks the bottom of the uni filter and here are the pictures. What could I do to prevent this happening besides removing the filter completely? Would the silly boost bottle setups keep the fuel from shooting back into the air filter?
You can see the white underneath the filter, that’s the wet fuel mixing with the oil in the filter.
You can see the white underneath the filter, that’s the wet fuel mixing with the oil in the filter.
FurryOnTheInside
In Memoriam
Can you print a degree wheel, stick it to some card, stick that to the magnet, remove the intake manifold and measure the degrees that the intake stays open (intake duration)?
I haven't measured mine, just didn't get around to it and no problems to diagnose but I think it would be helpful to be able to compare your intake duration to others/ the norm/ ideal to see if that is the root cause of your intake reversion.
Street Ryderz
Well-Known Member
Can I ask what is between the carb and what appears to be a rubber coupler attached to the intake? And what's the I.D of that peice?Those air filters are great I dont think that the little bit of accumulated oil and fuel would affect it that much.
Sumsloppymeet
Active Member
I don’t quite understand how to do this? Do you have pictures of how to do this?
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The photo of my air filter is only showing what looks like a little bit of gas underneath the filter. But the entire underside of that large filter will be soaked in gas when I’m done it’s definitely what’s causing the issue. As for the intake piece I cut a small piece of heater hose I bought from the hardware store and used a small piece of self sealing high temp silicone tape at each point in the manifold. I stretched and wrapped the tape very tight over the hose and metal intake connections. It makes the extended intake airtight and very easy to remove and re-work if necessary. Once I have the connections made I use a zip tie to hold the tape for safe measure. The hose is 3/4” ID 1” OD.
It gets enough gas in the filter that if I hit a bump hard enough while riding I can feel/smell gas shake off the filter and drop on my leg or foot. The engine runs just fine without the filter, it only starts acting like this once I have the filter on; Four strokes a lot and bogs on throttle once the filter gets covered in gas from the reversion. If I run it long enough at WOT it seems like the filter will clear out enough and run normal.
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