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Dear Jon,

I have recently fitted new reeds to my bike these are different to the set that I took out. The new reeds are black and have a sort of zig zag pattern at one end. I noticed that there is no gap when I put them on one way and about a .5mm gap when on the other way. The bike is not starting or even firing. I have checked carb ,spark, compression and all these seem to be fine. Are there any other ways I can do diagnostics.

Cheers Chris ,Scotland


Those are probably the newer Carbon Fiber reeds. The zig-zag pattern on the sealing lip is to enhanse flow at low speed and minimum lift while still providing stability by having a fairly large sealing area. Install them so there is no gap. Use Locktite on the screws and try not to overtighten them. For a bike engine to run, you need several things. 1) Good fuel, properly atomized 2) compression and 3) a strong spark at a reasonable time before top dead center. Sometimes a spark will show at the plug (yours should be set at about .020") when it is removed from the cylinder but the spark will not jump the gap under compression inside the engine if the ignition system is weak. I'd run a diagnostic check with a meter on the ignition components and make sure all the connections are good and the system is properly grounded at the appropriate point. I'd also disconnect the kill switch just to be sure this isn't the problem. If your bike has been stored for any length of time, I'd put some fresh gas (with premix at 80 to 100:1) in. The "high-end aromatics" will dissapate from pump gas at a faster rate than race gas. Check these things out and let me know if you get any results. I can get you the correct readings for the ignition components if you need them.


Professional tuner and 'Trials Competition' writer Jon Stoodley has very kindly stepped up to the plate to answer your questions. If you're having problems, or need some advice just send an email to Jon. If it's something that could be useful to others, we'll post it on the site.
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