FZRSupport: the FZROnline Archive

I have just a few more questions as I tune up the old girl.
I have been reading about jets(main jets) and I have a slip on, a over sized cam, and had K&N dual port pods in this configuration the bike ran well with 130 main jets. The K&N`s gave up and no longer wanted to stay attached to the carbs, so I replaced them with individual pods now I can tell the bike had more power on the low end, but it runs out of steam past 7k rpm so I have gone up one size to 135`s. With the 135`s it doesn`t appear to have changed. but still starts and idles well.

Am I heading in the right direction by going up another jet size? Is there a jet size that is getting to big?

I was thinking about going to a 520 chain on a 15/50 and I was looking at the sprocket and chain combo`s offered by sum of all parts, are they quality parts or will I regret getting them?

Thanks all!

When you say it runs out of steam, does it not rev past 7k or just doesn't have any power? Have you read your plugs yet?

Sum of all parts have good stuff.

megaloxana wrote:When you say it runs out of steam, does it not rev past 7k or just doesn't have any power? Have you read your plugs yet?

It revs, just has no power, Like I said the bike has been running great for two years and with the new pods(only thing that changed) clearly there is a lot more air going in, This is just my first experience doing jet work and I don't want to get up to like a '170' and find out that it works great but is the wrong way or potential hazardous, I'm learning here as I stumble along.

Thanks

Sum of All Parts are very good quality, they are Vortex sprockets and RK X-Ring chains. You will not be disappointed. I am getting the kit after I get back from my cruise in a couple weeks. Then I will put on the new tires, Fox TC, and 520 Conversion. Hell should be a differnt bike after that, LOL

Any more input on the jeting?

Thanks all.

Well jumping from 130 to 135 you should notice a difference. Im not sure how much more airflow you get from individiual compared to dual pods. Id say go for a WOT high rev ride and pull the plugs to see whether you are running rich or lean.

Revs freely but no power = lean. Do a plug chop, but I'd suggest you go up two or three sizes first - fouled plugs are cheap compared to holed pistons! If you have a set, drop in fresh plugs for your plug chop - and I do mean CHOP! WFO as far as you can hold it (traffic and police have some severe influence here!), then clutch in and hit the kill switch. Don't just idle down, down shifting all the way; you'll mask the top end reading with needle and idle burn patterns.

Your main jet will have rather little effect on the 'starts & idles' part. You really do have to be nearly WFO to get on the main; you will see some influence in the mid-range, but that is still dominated by the needle.

I would love to ramp up the RPM`s and check the plugs but I can`t get the bike past 6-7k I need to get that first.

I pulled the carbs tonight and dropped the clip on the jet needle, went down on position(from #2 from the top to #3)(more fuel), and rode it now the dead spot is at 5k RPM`s and feels like its flooding now, so tomorrow morning I`m going to put the clip back in its original position (#2 from the top) and jump the jet up to 145`s or 150`s if I can find them and see how it goes.

Once I can get it running across the RPM band then I`ll worry about a plug run.

space_weazel wrote:I would love to ramp up the RPM`s and check the plugs but I can`t get the bike past 6-7k I need to get that first.

Hey space_weazel,

I've never done a plug chop before but when Don says WFO he's really referring to the throttle position (not necessarily how fast the motor's spinning). The two ARE intrinsically linked but there IS a distinction to be made here. He (Don) and a couple other guys would be able to explain it much better than I can. The idea is to put the bike under load (going uphill for example) with the throttle all the way open, then, as he said, pull in the clutch and hit the kill switch. Doing this basically allows you to look at the condition the plugs are in when there is a maximum of fuel and air hitting them. This will help you decide what MAIN jet size would be appropriate for your air flow. From what I understand, the main jet is where you need to start first when "designing" your carb spec. Slowing down normally basically "covers up the tracks" with regards to what the fuel / air mixture is when wide open because you now have different fuel / air delivery happening (via the different circuits).

Hope I'm not too far off base here!

Brandon

Brandon, Weasel - I may have gotten ahead of myself. If the bike won't rev up it might not pull enough air to lift the slides for a true main chop; you may still be on the needles. I'm so used to slide carbs I sometimes forget CVs don't quite work the same. (7k revs on a 600 is 2/3 the way up the tach, wide open butterfly - yeah, it's still worth a try. I'm flip-flopping like mad here because 7k is a little more than 1/3 up my tach, and the slides wouldn't be full open at that point)

Weasel - I've just reread the thread, and noted your comment from last Tuesday about being worried about going rich and getting into a dangerous situation. You won't break your bike going rich; you CAN melt things going lean. A situation where adding more air = won't rev out means it's SERIOUSLY lean.

What happens when you hit that magic 7k wall? Does it simply stop revving up, holding a fairly clean line, or does it act like it's hitting the rev limiter - "Gagagagagagaga"? (Sound effects by THX )

If you have no larger jets (the #170 mentioned tongue in cheek above might not be a bad idea) try this old trick - take the main jets OUT! You should get to the rev limiter / gagaga effect at some point, as the engine loads up with fuel and stops burning cleanly; I'd be curious as to where that rev / throttle point is. Drop your needles, try it again - any change?

A thought - can you rev it to red line in neutral? If not, something electrical is going on. The FZRs are notorious for losing revs as the battery / charging system dies, and the combination of weak spark and weak mix (perhaps not dangerously so) may be the issue.

Do you still have the dual-pods? Reelrazor posted a trick on the other board about carb boots a little while ago - soak the rubbers in hot coolant (not boiling) for a few hours; it has additives to keep the hoses suple, and works a charm on carb rubbers. Obviously, don't immerse the fabric filter.

I have moved the Carb discussion over here viewtopic.php?f=8&t=3341 with updated and corrected info and explanations.

When it hits the wall it is not clean, it revs and sounds like its choking, sputtering
hop on over to the new thread to see what else I have tried.

Thanks guys