102 jets in carbs

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gloves86
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102 jets in carbs

Post by gloves86 »

Just stripping my carbs and degunking them, and when I took the jets out they're labelled 102. In the manual it says that 98 is standard...

Now I've got a straight through system (not my choice) so I guess that's the reason for the bigger jets. Before the head gasket went the plugs were a nice colour, so I know the fuel/air mixture was good for most of the rev range. Problem is it overfuelled on idle to the point of making my eyes sting! Question is - should I leave the fuel air/mixture as standard (2 1/4 turns or whatever it is) or should I dial it in a bit to reduce overfuelling on idle?

I'm a bit worried if I do this that the fuelling further up the revs will be messed up (guessing lean) - what do you guys think? Should I go back to 98s and put a removable baffle system on or just leave it as it is? Is it doing any damage to the bike with the bigger jets and overfuelling on idle?

One other thing - what's the gap on the plugs supposed to be set at? They're c9rek (double electrode finger thingys) if that makes any difference...

Thanks in advance! :)

Rach.
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RedexRobB
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Re: 102 jets in carbs

Post by RedexRobB »

plug gap iirc is 0.7-0.8 mm :)

If its running and riding good then leave it as is, otherwise you could get it dyno'd to get it done properly if your that worried. The air mixture screw (pilot jet) only acounts for down low revs, it doesnt alter anything up the top end as thats what the main jets and needles are for (someone correct me if im wrong).

How do you know if its overfuelled? If the plugs are a nice lightly toasted brown you dont really need to change anything.
gloves86
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Re: 102 jets in carbs

Post by gloves86 »

I think it's overfuelling only at idle because it stinks of fuel and stings my eyes when I'm sitting in traffic lol

my other half asked someone at work who knows about carbed cars etc about the 102 jets and he said it makes it overfuel loads on idle as well. There's no physical evidence it's overfuelling, like you said the plugs were nicely brown before the head gasket went. It did keep cutting out when I stopped at traffic lights though, but that was just more annoying than anything else.

If the pilot screw only accounts for low down revs, would turning this in a bit counteract the larger jets and reduce the amount of fuel getting through on idle?

Thanks for the help Rob.

Cheers.

Rach.
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jake
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Re: 102 jets in carbs

Post by jake »

No, the idle mix screw wont effect anything other than just that, it then goes on to the needle and mains.
If its that rich on idle its making your eyes sting! it should be cutting out on idle. Id suggest a fuel leak
gloves86
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Re: 102 jets in carbs

Post by gloves86 »

cool thanks Jake. I'll dial the pilot screw in a bit then to cut down on the amount of fuel coming through on idle. I'm pretty sure I haven't got a fuel leak, was the first thing I thought when I smelt the fuel, but all the connections and pipes are nice and dry and the bike doesn't smell of fuel when I go in the garage in a morning.

Will try the pilot screw at 1 and a half turns out and see what it's like!
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