Spark Plug Head Scratcher...

[Architecten]

I've been running in my RT200 and the first 250miles the carb set up was pretty rich to keep everything safe and lubricated. The scooter was fine but would bog down in low gear and wouldn't go to idle and would be a mare to start if it stalled. But it would always start after a couple of kicks after leaving for a bit or next day.

A couple of weeks ago I rejetted the carb and the the scooter is now running much better.
Current set up is

Idle 50
Needle X7 2nd clip
AV262
Main 110

I've been tinkering with the idle and it's nearly there but the airscrew is right in so will try dropping down to a 48 or 46. I'm also going to up the atomiser to an AV264. It will still stall when running due to spit back but starts straight away again quite happily... so far so good...!

The problem is if I leave it any length of time it takes ages to start or not at all unless I change the plug?! and it doesn't need to be a new one???? Once changed it starts first kick with choke full on and goes to tickover straight away....!!!

Any ideas...???!!

[Architecten]

I'm actually thinking this is jut a crap batch of B8's I've acquired. 3 over the last 2 days can't be a coincidence?!

[tonydevon]

Loads of fakes on ebay.

[Clubbook2]

I've had the same problem. BR9ES bought at kettering.
2 interfere with sip speedo (? Not resisting)
One doesn't spark at all!

[Daggs]

Sparkplug mmmmmmmmmmm people get hung up on sparkplugs. It's just a simple device for creating a ..... spark.
The PROBABLE reason it starts after a plug change is; the fresh air entering the compression zone + a dry plug.
The fault is PROBABLY in the jetting.

[Andy Pickering]

Are you using a filter Nick ?


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[Architecten]

Ramair on a bell mouth through the side panel.

I know it could be jetting and I'm getting loads of spitback but it's odd that when it was jetted richer it started ok?! When I remove the plugs they're not particularly wet. And once the another plug is in the the choke has to be full on??

Some new smaller idle jets arrived today so I'll get some new plugs and see what happens next week.... it's never dull!

[Andy Pickering]

I'm not a fan of filters to be honest, I might be wrong but I'm sure going up with the atomiser will increase the spit back ? Try a Nippon denso plug, main looks a little small from my experience but they all do vary tbh, if possible get it to a dyno, keep checking the plug


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[Architecten]

I'm only going up on the atomiser as it was recommended by MB. I can always come back down again. Just trying to get close before bothering with a dyno. Needs a couple of hundred more miles in the engine as well... not sure about the main as I haven't really gone to full throttle yet. Although spitback was a problem it's much better since going to the X7, might give the nippon plug a go. I do have my doubts about the plugs I've got though.... 4 for a fiver on ebay? mmmmmmm.....

[Andy Pickering]

I'd go back rich till it's run in Nick then go from there,


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