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[Lee June woo]

@ Vince : I`m using NGK spark plug. I`ll try Install champion. Thanks.

Thanks for all of you!

I`ll try solutions step by step.

Thanks again.

[Adrian]

There's something in the back of my mind from somewhere (I'm sorry I can't remember where) which advised against the use of standard cams on the 612 conversion, it needs performance cams to work properly. Have any of you gentlemen come across this too, and if so can you remember where?

Twin plugging your cylinder head might help, though if you're relying in the decompressor to aid starting you would need to modify the cylinder head by moving the decomp valve, do a search on the forum archives for Tim NZ's post on how to do it.

What ignition system are you using?

A.

[Wheaters]

Rather than fitting two head gaskets, I would prefer to get a de-compression plate made. Two gaskets aren't designed to work together and it can cause a leak. Having said that, using one copper gasket next to the head, sealed with a non-setting sealant such as Wellseal, could probably be used with a normal composite gasket below that onto the barrel, fitted "dry".

I've just had a decompression plate made in aluminium for my trials car, which has a 3 cylinder, 993cc supercharged engine. On this engine, a 1.5 mm thick plate lowers the CR from 9.5 to 8.25. Because the block, being from a car, is all in one piece, I had to fit the plate adjacent to the cylinder head casting (with a sealant, as above)and a normal head gasket between the plate and the block.

However, on a bike engine like the RE, it's more straightforward because the plate can be fitted below the barrel, with a base gasket on each side.

[Lee June woo]

@ Adrian @Singleminded

My ignition type is points !

[Bullet Whisperer]

With standard cams, I would definitely retard the inlet cam, or else the cylinder pressure on the compression stroke will go through the roof and cause violent pinking !!

[stinkwheel]

With standard cams, I would definitely retard the inlet cam, or else the cylinder pressure on the compression stroke will go through the roof and cause violent pinking !!

Thre you go Lee June woo. Straight from the expert and a nice easy modification to try.

He even did a video showing how to do it:
https://youtu.be/nUEg4eDN_LY

[Adrian]

Thanks, it looks like you have a number of things to look at before fitting a different ignition. I have posted recently about retro-fitting a manual ignition control BTH magneto on an Indian Bullet, but evidently that might not be the solution.

From what others have offered, let's see if I can distill their advice into a few quick points.

1. Check that your compression is not excessive and use a decompression plate if necessary.

2. Fit stronger springs on the advance and retard bob weights.

3. Retard the inlet cam wheel by one tooth. My AVL hybrid with a 10:1 compression (only a 500) also had a noticeable pinking/vibration problem which was much relieved by following Bullet Whisperer's advice here, not completely, but much reduced, and with no obvious loss of top-end performance.

4. Drop down to a 19T gearbox sprocket and remember to use the gearbox, you have that nice 5 speed box to play with.

5. Lift your carb needle by one notch.

6. Anything else they wrote which I have missed!

A.

[Lee June woo]

Thank you for all.

I`ll check all of these advice. !!

regards.

Lee June Woo

[Pantherman]

First, check that you have exactly the right spark plug for the bike and that your ignition timing is correct. I had the same problem with my 500cc Bullet ; the plug was more-or-less okay and I spent hours messing around with the ignition timing etetc. Then I bought the correct spark plug; end of problem. Different plugs have different heat ranges and a plug that runs a bit too hot will cause pre-ignition once the engine attains its running temperature.

Do the simple stuff first!

[Daiwiskers]

I know that I've said it before on the forum

But could it be the fuel line breaking down fuel lines do not like ethanol fuel

I like a clear fuel line but it's proving almost impossible to find a clear line that will last (I have yellow Tygon on at present)

Could also be a fuel tap issue not letting enough through when under load