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Title: A65 Thunderbolt Strobe Timing.
Post by: Wilf2019 on 01 Mar, 2021, 09:11

Hi All,

How do people determine the correct rpm for strobe timing on a Thunderbolt with no tachometer?

Thanks in advance.

Title: Re: A65 Thunderbolt Strobe Timing.
Post by: DAVE BRADY on 01 Mar, 2021, 09:56

Hi,

I usually rev the engine to half throttle and hold it there for a few seconds. At this point the bike is moving backwards on the centre stand. This seems to work OK. I have a digital rev counter made for tuning chainsaws. With the engine running it is held close to the plug and the revs are indicated. It also has lead if needed. I also used this to determine that at my engine is revving at 3500 rpm when doing 60mph.
The rev counters should be available in most chainsaw suppliers or probably on line.

Dave.

Title: Re: A65 Thunderbolt Strobe Timing.
Post by: Bess on 01 Mar, 2021, 10:06

Hi,
I use a strobe with an integral rev counter, something like this:

https://www.ebay.co.uk/itm/AccuSpark-Professional-Timing-Strobe-Light-Lamp-Digital-Rev-Counter-SP8000-/201239704597

Best wishes...

Title: Re: A65 Thunderbolt Strobe Timing.
Post by: Wilf2019 on 01 Mar, 2021, 19:32

Thanks for the reply's both.
That's good to know.

I've just bought a strobe but I wish I knew about the one with the in built rpm display.

I've just fully rebuilt the engine so I think I will run it up a few times before I leave it running for too long to check the timing.

The good thing is that it started and run 2nd kick.

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The BSA Workshop => Twins => Topic started by: Wilf2019 on 01 Mar, 2021, 09:11