Author Topic: Gen1 airbox mod? (Read 11165 times)

Motopsycho87 · « **on:** 01 February 2016, 05:13:48 pm »

Hi all, just wondering what the airbox mod is for the gen1 fzs1000? Seen it referred to many times but can't find any images?

markie_wales · « **Reply #1 on:** 01 February 2016, 05:32:22 pm »

Been out of the loop for a long time[1], but from memory for the "Full Monty" Ivan's mod, you need to Dremel out the ribs on the inside of the top of the air box lid. Caveats:

1) as I say I've not own a Gen 1 for ~9 years,
2) if not related to Ivan's Full Monty - no idea,
3) I'm 9 years older and I may have not remembered exactly what needs trimming away.

cheers

Markie

[1] but hopefully will be back soon

PieEater · « **Reply #2 on:** 01 February 2016, 05:45:47 pm »

Quote from: Motopsycho87 on 01 February 2016, 05:13:48 pm

Hi all, just wondering what the airbox mod is for the gen1 fzs1000? Seen it referred to many times but can't find any images?

As Markie has said the only time you would want to modify the airbox on a Gen1 is during the fitting of the Ivan's Full Monty jet kit, otherwise you're going to ruin the bikes mid range power. Maybe you could go back to one of the places you've seen it mentioned as I suspect this was referring to the Gen2 rather than the Gen1.

http://foc-u.co.uk/index.php/topic,18397.0.html

http://www.yamahafz1oa.com/forum/showthread.php?t=17064

Motopsycho87 · « **Reply #3 on:** 01 February 2016, 06:37:22 pm »

Well the bike has a full akro and has clearly been rejetted. But came with a receipt for fitment of a new airbox as it must have had pods fitted. It's running a little rich, so the easiest way to lean it is to open her up to breathe. It's got a k&n, but the airbox looks really restrictive.

Falcon 269 · « **Reply #4 on:** 01 February 2016, 08:00:24 pm »

Be careful with the link to the US FZ1OA forum thread on this subject as the photo on the first page is incorrect. Post #16 shows the correct mod.

PieEater · « **Reply #5 on:** 02 February 2016, 06:09:57 am »

Quote from: Motopsycho87 on 01 February 2016, 06:37:22 pm

Well the bike has a full akro and has clearly been rejetted. But came with a receipt for fitment of a new airbox as it must have had pods fitted. It's running a little rich, so the easiest way to lean it is to open her up to breathe. It's got a k&n, but the airbox looks really restrictive.

I think that information would have been useful in your original post. I guess it would be useful to confirm that the bike has been rejetted and with what kit check out the last post on the following.

http://foc-u.co.uk/index.php/topic,19189.0.html

Motopsycho87 · « **Reply #6 on:** 02 February 2016, 10:02:57 am »

I just went from the fact that the bike came with a dyno sheet, 131rwhp. And was very rich 5000 rpm up.There is also a receipt for fitment of a standard airbox, as an owner previous must have had pods. The bike runs really nice, but is clear that it's running rich up high.

I've cut the box as per the pictures, then run a sandblaster in it pointing in the direction air should be flowing. Looks good to me

!

With regards to the link that was posted, very useful, next time the carbs are off (I'll clean and balance them in the not too distant future) I'll have a look and really see what I've got!

Motopsycho87 · « **Reply #7 on:** 02 February 2016, 10:14:57 am »

Not the best air fuel ratio!

PieEater · « **Reply #8 on:** 02 February 2016, 04:54:41 pm »

I think you've been a bit rash but I hope you're happy with the results.

Do you actually know at what point in the bikes history that Dyno was taken (before / after the exhaust system, supposed pod filters, stock filter)? The air/fuel results are not what I'd expect to see with an Ivan's jet kit even with an unmodified air box, also a bike with an Ivan's kit, K&N plus full race system would be making about 140rwhp not 130, mine with a cheap end can makes 134. I kind of think you've been jumping to conclusions based on supposition which is why I suggested you check first, however you were obviously in a hurry ......................

Hopefully Mike (Falcon 269) will be back again with his thoughts on the Dyno chart.

Motopsycho87 · « **Reply #9 on:** 02 February 2016, 05:49:18 pm »

Then jet kit comes soon

. I did it because I have the workshop available. It idles a lot better now, suggesting some alteration. The dates of the invoices I have show that the dyno was done after the airbox was refitted. I wasn't too fussed if it upset the bike as a second hand airbox is pennies.

Which kitshould I be buying with hacked box, full akro and k&n? It's definitely improved, and removed a bit of the flat spot I could feel, but obviously if there's a kit made specifically to suit, its better than stabbing in the dark!

Motopsycho87 · « **Reply #10 on:** 02 February 2016, 06:07:32 pm »

Have to admit, it surprises me that there's no info where people have jetted the bike themselves? Every bike I've owned I've jetted through trial and error and there's loads of info about different needles, mains etc

Falcon 269 · « **Reply #11 on:** 02 February 2016, 07:38:39 pm »

Dyno chart looks suspiciously like someone raised the stock needles but didn't reduce main jet size.

The DIY owners did their thing in 2001 when the Gen 1 first came on the market. The pro tuners took over soon after and the pick of the bunch are Ivan's kits.

PieEater · « **Reply #12 on:** 02 February 2016, 07:53:47 pm »

And this is my Dyno chart with Ivan's kit as fitted by Mike, the tester couldn't believe how spot on the fuelling was.

Motopsycho87 · « **Reply #13 on:** 02 February 2016, 09:01:58 pm »

Wow. I'm sold, will order on payday. That is insane.

Motopsycho87 · « **Reply #14 on:** 02 February 2016, 09:04:51 pm »

Can they be ordered off his website? Or is there a UK dealer?

JKay · « **Reply #15 on:** 02 February 2016, 09:52:49 pm »

Pm falcon he's the man for ya

Falcon 269 · « **Reply #16 on:** 02 February 2016, 11:09:31 pm »

http://www.sgmotorsport.biz/

Mention to Stephen that we sent you.

You need Ivan's MB jet kit, not the Slip-On version. You also should modify the intake stubs to get the best possible out of all the mods.

http://www.yamahafz1oa.com/forum/showthread.php?t=47373&highlight=intake+boot+mods

Motopsycho87 · « **Reply #17 on:** 03 February 2016, 09:53:37 pm »

MB kit is on it's way. I'll match the boots when I have the carbs off. I'm pretty certain the old boots were matched as they had marks in from being ported, but they were so cracked I didn't want to keep them.

Falcon 269 · « **Reply #18 on:** 03 February 2016, 10:50:18 pm »

Yes, those have been done - but not by me ...

Motopsycho87 · « **Reply #19 on:** 04 February 2016, 06:13:43 pm »

Which leads me to believe I may find the carbs have been drilled etc already. I know the jets were changed for the dyno, needles and mains were changed back to standard... What tools do you use to port the boots? And exactly how much do you take out? I can see it being difficult to get them exactly the same?

Motopsycho87 · « **Reply #20 on:** 04 February 2016, 06:15:52 pm »

Or is there anyone in the UK that can do the boots well?

Falcon 269 · « **Reply #21 on:** 05 February 2016, 10:11:50 am »

You need a Dremel type tool with sandpaper roll and then a spearhead stone bit to do the intake stubs:

http://www.yamahafz1oa.com/forum/showthread.php?t=47373&highlight=intake+boot+mods

No need to get them absolutely identical. The aim is to remove the lip between stub and cylinder head and to get rid of the hump in the floor of the stubs.

If the previous owner refitted standard needles and main jets to carbs which have had the pilot circuit bypass holes drilled, no wonder the fuelling is completely wrong.

Motopsycho87 · « **Reply #22 on:** 05 February 2016, 09:45:59 pm »

Will get started on them this morning, I've read about how much difference they make and felt the power drop when I put some new stock ones on, I had a feel and the lip is huge!!! What a fail on manufacturing!

Do you know if you can choose not to clip the springs, but still enlarge the event holes on the slides? The supplied guide makes out as if the holes are recommended and the spring is optional, but loses some low rpm response?

Falcon 269 · « **Reply #23 on:** 05 February 2016, 10:10:52 pm »

I drill out the throttle slides and cut only 1cm off the springs, a compromise that seems to work. I've done it both ways and to be honest, you'd struggle to feel any difference.

Motopsycho87 · « **Reply #24 on:** 05 February 2016, 10:19:39 pm »

Fair enough, so I won't miss out if I leave it you think? I'm trying to see how allowing the pressure to equalise above the slide allows it to open quicker, bearing in mind it's atmospheric pressure above... Can't get my head around it!

Where as altering the spring obviously allows the slide to sit higher for the same throttle position...?