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Setting base timing without reference marks

Practical Standalone Tuning

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I have a Honda CBR1100 that has a dry sump system on it which is fitted onto the end of the crankshaft. The factory marks are behind the dry sump system and there is now nothing visible that I could make my own marks on. The only visible part that turns is the prop shaft but no 1:1 ratio.

Any ideas?

Its on an ECU Master Black.

I've been there. Here how one guy solved it: Mark the flywheel / drysump pulley / whever you can by dead stopping the engine. Now get a spare cover, machine a hole that allows you to see the mark at top dead center when aligned with whatever mark you put on the case or cover. Cover the hole with a clear window (old safety glasses work well), just silicon it on so that splashing oil stays inside.

Now you can time the engine. Here's a pic of a KTM 450 done that way:

Attached Files

Thanks for the info I will see what I can do.

Just another thought, is it possible to somehow use a Pressure Transducer on a PicoScope?

I've done that too! Connect the pressure sensor, and the ignition trigger from the ECU. Adjust the necessary offset angle to align the pressure peak and the ignition trigger at 0 deg timing.

It's useful for a rough start but there was no way to get closer than a few degrees. I didn't care since I was tuning the whole ignition map from scratch on a dyno.

It's a bit fiddly, but I'd suggest using a dti or piston stop to get the split on the piston position, as normal practice, with a degree wheel to find the TDC point. Then mark the dry sump pulley and crankcase/front cover with new TDC marks. If it's a bit awkward to access the pulley/cover, or whatever with the wheel in place, remove it with the engine at TDC and mark it. If it's still a problem, fabricate a stiff pointer to align with the pulley mark that can be fixed to the engine.

You really only need it for synching the initial timing mark and the ECU TDC in the software, which can usually be done at cranking with the plugs out,so any pointer, or whatever, can then be removed.

Depending on the engine, and installation, you may be able to remove the clutch cover and mark that instead - I'm sure with a bit of thinking you'll come up with something that works for you.

However, as David suggested, if doing the tune from scratch rather than loading a map already being used, approximate should do the job - you just need to get it close enough to get the engine running and work from there. it is better to have it correct, though, if practical, for rebuilds, etc.

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