How lean without risk?

Hi,

I've a Suzuki Quadsport Z400 (2004 model) and I'm jetting it.

I bought a full exhaust system (CT Racing), a K&N filter with Outwears, a Dynojet kit and a #25 pilot jet.

I removed the lid, installed the pipe and the filter with Outerwears, and tried the

#160 main jet, 3rd clip on the needle, 25 pilot, and 2.5 turns out on the fuel screw.

It run fine, better than stock. Then I tried the #155 (everything else equals) and it run better, more top end. Next I tried the #150 (the recomendation from Dynojet instructions) and it run better than the 155.

I live in Spain at 1500 feet and a temperature from 50 in winter to 90 in summer.

The point is that all the people I know from z400central or thumpertalk with the same configuration as me (full pipe and no lid) use bigger main jets, even with higher altitudes. I think a #150 main jet will be lean, but is the configuration that has a higher performance.

The question is, is the 150 safe or maybe i'd have to choose the 155 main jet?

On the other hand, I don't ride at full throtle all the time (I use the quad for trails, not mx).

Thanks in advance!

if a 4 stroke is lean enough to hurt itself they run noticeably bad.if your quad is pulling hard at high rpm you are safe.

Ok, thanks a lot!

Greetings from Spain!

Remember that Dynojet jets are on a slightly different sizing scale then equivelent sized Keihin or Mikuni jets. So, when comparing your jetting to others' jetting it's apples to oranges unless your all using OEM jets vs. Dynojet jets.

dj and mikuni jets are close enoguh in actual measured a/f ration to be used interchangeably.

yes,i know what dynojet says.

dj and mikuni jets are close enoguh in actual measured a/f ration to be used interchangeably.

yes,i know what dynojet says.

Dynojet and Kiehin are not though, right? Or are they?

correct,kehin is a bit farther off.

when I compare my configuration I always look at other bikes with dynojet kits.

Added to this, I agree with burned, because of the end dimension of the dynojet kit, 7% smaller at full throttle than the stock one (mikuni), mikuni and dynojet main jets are almost the same...

look at this link:

http://www.z400central.com/invision/index.php?showtopic=36930&hl=

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