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2008 RMZ 450 wasted spark ignition (tach)

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First of all this is a really decent site - plenty of great info to be found here. Thanks for that.

I have tried searching this topic but have found nothing specific to the 2008/09 RMZ 450.

Does anyone know if the 2008 has a wasted spark ignition (fires every revolution even though it only really needs to fire every second on the power stroke) or if it only fires every second revolution on the power stroke?

The reason I ask is that I have installed a Hardline hour meter / tach and the RPM appears to be out on the low side by a factor of 2 (i.e. with a decent sounding idle at 47 turns out on the idle knob the RMP reads 1000 RPM when it should be 2000 RPM). The Hardline tach is designed for 1 spark / rev which would work fine for 2 strokes and 4 strokes with a wasted spark ignition. These hour meter / tachs (actually made by Sendec) are used by a lot of people and I have never heard of anyone having an issue like I am having where the RPM reads only half of actual.

I am beginning to think that since the 2008 has a crank position sensor for the FI that it is smart enough to know when it is on the power stroke and only fire once every 2 revs. I am not sure if non-FI bikes have a crank position sensor or not. Or maybe my meter / tach is faulty?

I don't really need the tach for riding, but it was only $5 extra over the base hour meter and I thought I could use it for setting idle and checking oil pressure, etc. I can easily just multiply by 2 but I wanted to know if anyone else was having this issue. On the plus side I could in theory read to 16,000 RPM (8000 RPM on my tach x 2 - not that the bike will do much more than 10000 RPM anyway) whereas the tach is only designed to read to 8000 RPM in a wasted spark configuration.

Cheers :)

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According to the manual the bike only uses a crank angle sensor, which in my best guess would mean it is just like all the others and has a waste spark. If our bikes used a camshaft sensor then I would say it would only fire on TDC compression. The reason the camshafts turn 1 revolution compared to 2 revolutions of the crankshaft. So if we are only using a crankshaft sensor, the ECM cannot tell if the engine is on TDC compression or exhaust, so it would have to fire both times. Which would also mean the injector fires twice during the 4 strokes. Someone out there correct me if my logic is wrong.

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Bellec,

Thanks for the feedback.

I took a closer look at my manual and there are actually 2 sensors: crank position and crank rotation. Even then when I think about it this would not allow you to differentiate from the power stroke or the exhaust stroke (you would have to, as you pointed out, look at the rotation of the cam shaft).

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Switch it over to the 2 stroke mode and try it.

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You are correct that the unit is preset for 1 spark per / rev. I am not aware of any way to adjust it. I originally started with 5 wraps on the sensor wire per the instructions, but I also tried anywhere from 2 to 8 wraps, but it made no difference.

I also tried re-routing the lead wire so it was away from the coil and so there were no loops where I bunched up the extra wire and it still did not make any difference.

I can't determine if this is a problem for just 2008 and on models. Do you have one on your bike and if so, what year is it?

Thanks for the feedback.

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First of all this is a really decent site - plenty of great info to be found here. Thanks for that.

I have tried searching this topic but have found nothing specific to the 2008/09 RMZ 450.

Does anyone know if the 2008 has a wasted spark ignition (fires every revolution even though it only really needs to fire every second on the power stroke) or if it only fires every second revolution on the power stroke?

The reason I ask is that I have installed a Hardline hour meter / tach and the RPM appears to be out on the low side by a factor of 2 (i.e. with a decent sounding idle at 47 turns out on the idle knob the RMP reads 1000 RPM when it should be 2000 RPM). The Hardline tach is designed for 1 spark / rev which would work fine for 2 strokes and 4 strokes with a wasted spark ignition. These hour meter / tachs (actually made by Sendec) are used by a lot of people and I have never heard of anyone having an issue like I am having where the RPM reads only half of actual.

I am beginning to think that since the 2008 has a crank position sensor for the FI that it is smart enough to know when it is on the power stroke and only fire once every 2 revs. I am not sure if non-FI bikes have a crank position sensor or not. Or maybe my meter / tach is faulty?

I don't really need the tach for riding, but it was only $5 extra over the base hour meter and I thought I could use it for setting idle and checking oil pressure, etc. I can easily just multiply by 2 but I wanted to know if anyone else was having this issue. On the plus side I could in theory read to 16,000 RPM (8000 RPM on my tach x 2 - not that the bike will do much more than 10000 RPM anyway) whereas the tach is only designed to read to 8000 RPM in a wasted spark configuration.

Cheers :thumbsup:

100% sure the bike is wasted spark. No camshaft sensor.

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Put one on my 08 today and it does the same as yours, with hot start lever pulled it reads 1840. Ervin.

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Hardline has not responded to my email yet.

If you needed it for maintenance / idle setting, it will work fine (just double the value you read).

If you wanted it for real time feedback when riding, the unit responds fairly slowly anyway so it would only be useful in steady state riding (takes a few seconds to register the RPM changes...and then you would still have to double it).

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Are you sure that you have your idle set close to 2000 RPM? Because 2000 RPM is a lot higher than what you would run on a carbureted bike. If I set mine to where it sounds like a similar idle speed as my carbureted 250 it sounds like a good idle, but it is no where near 2000 RPM it is closer to 1000.

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I can't be 100% sure (since I can't measure it), but I am probably 95% sure that I have the idle in the ballpark for the following reasons:

1. I have tried revving the bike to get an indicated 2000 rpm and I would have to say that it is running way faster than any bike I have ever heard at idle (I would be scared to try and put it in gear at that speed for fear of the clunk it would make).

2. I have seen plenty of videos of the 2008 (from magazine tests to youtube) and when those bikes are idling they would sound similar to mine.

3. I am 47 turns out on the idle knob (from what I understand 42 is stock).

4. Ervin posted that he had the same issue that I did.

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ON mine what seems like a reasonble idel speed it reeds about 1100 RPM.

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Once the weather breaks and I am actually able to ride the bike, I will try to get out in an open area and get some revs into it. If it revs out and I am only reading 4500 - 5000 RPM (approx. half of where actual redline would be) then for sure I know the RPM is off.

If it reads 8000 RPM (the max the unit can apparently read) then I guess it would all be in my head and I would need to crank the idle up (however there is no way I would crank it up to an indicated 2000 RPM).

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Just digging this thread up to see if anyone got an answer from Hardline/Sendec. I just got an 08 and installed the hardline hour meter/tach, and it too reads low. I even pull the one off my Honda and ran them at the same time. Both read low -- 800-900.

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The 08 RMZ450 does not use a wasted spark system.

I run a Trailtech Vapor on my bike and it reads proper RPM with the spark/rev setting at 0.5. This means the engine fires every 2nd revolution.

Karl

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The 08 RMZ450 does not use a wasted spark system.

I run a Trailtech Vapor on my bike and it reads proper RPM with the spark/rev setting at 0.5. This means the engine fires every 2nd revolution.

Karl

I do not see how this is possible. The bike has no camshaft sensor, it has no idea which TDC on the flywheel is the power stroke. It has to fire every revolution.

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