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Hi Luke;

Read Louis post on his 3ma hybrid they explain primary needle tubes niceley in the post. Your needle tubes have holes in them that allows air to mix with fuel before it goes into the carb intake, which is making setup difficult.

Edd

Edd;

Right ok will do that.

General;

I have made some excellent progress today

I couldn't resist trying her with no air box. So I did.

setup:

320 mains
90 air jets
needles one up from lowest position
3ma3 needle jet
air box lid off

Result: Does still have the problem in the 4500- 6500 rpm range, but felt a little more alive and wanting to race

Action: I then put the 130 air jets in and what a change.

The rest of the set-up was the same as before accept 130 FAJ.

I made a vid which is uploading now. will put it up as soon as its done.

But I haven't gone above 7500rpm, just because I am a little scared its too lean in the top end. I will do lots of plug checks. I only went for a little ride, and noticed that it hit a few spots between 4500 rpm and 6500rpm in the beginning but I'm sure that was just because it was still a little cold. The rest of the vid I tried to slow down and ride at lower revs to see if the problem would start but I only noticed that it hit a spot at 6000rpm very marginally. So marginally that you can hardly even notice it.

All I can do now is pray that the top end isn't too lean.

here is a pic of the right plug after that short ride I went on. Before that I checked and it was almost black ( from the previous set-up with the 90's)



It looks a little darker in person. The lighting from the pic was very bright.

What do you guys think for a first plug check? 7-8000rpm at half throttle for 5 to 10 mins?

Now I am really getting exited

Hi Luke,

I don't have any experience with setting up my 3ma as it is still in a pile of bits in my garage and will be for some time.

But I would say that you are much better trying to get the top end fuelling sorted and safe before trying to get the part throttle carburating nicely. Because what you will find is that the mains/FAJ combination that gives good part throttle response may not supply enough fuel at the higher revs (where the damage is easily done). I can see that you are already concerned about this which you are right to be. If it were my bike I would be running the VAJ system as it does a really good job of cleaning up the part throttle (on my 3xv anyway with a programmable). I appreciate that you have the standard cdi but I'm pretty sure that the VAJ opens at least one airjet in the range you are struggling with.

The trick is to get the 3/4 to full throttle fuelling pretty close (on the rich side) then fiddle with the needle settings and airscrew and VAJ to get the part throttle working nicely.

Dan

A bigger AJ will lean you out.
Like edd says you'll never get it perfect. See it as GP type characteristics. Just make it safe and ride it. Then take your time with small adjustments.

Just my 2 cents,leave the AJ as it is,put the airbox back as it was but change the air filter with a more "open" one like a Daytona or something,if its still rich(i hardly think it'd be),then try to dril 2 holes on the upper side for a start.

Hi Luke;

Glad to see you are making progress. Follow your gut boet and let the setup juices flow

Edd

Thanks Guys for the info. Appreciated it.

Edd;

Glad to see you are making progress. Follow your gut boet and let the setup juices flow

HAhahahaha, will do.

I am going to put the air box back on minus the snorkels and plus a few small holes and see what happens. Otherwise I think I might have to go one or two up on the mains.

Here is the vid. Ignore the low revs and part throttle because I am awaiting bigger pilot jets to sort that bit out. And ignore the first bit because the bike was a little cold. Basically pay attention to the rest of the vid that is left

http://www.youtube.com/watch?v=taleVmwPcDg

Sounds pretty decent to me, would love to hear her at WOT!

Nice and responsible riding there. Being careful not to screw it.
Sounds good. I think you're there.

Crank; You will hear it at WOT soon soon, just after I have checked that it will not blow up.

Ndwedwe; I think so too, I just hope its ok at 3/4 to full throttle at higher rpm.

Hi Luke,

It sounds good.

Some info to consider.

The airbox itself is well designed (don't think the Japanese made it in 10min)
The aibox has more functions then holding the airfilter, ore sound redusing.
One of the main functions is getting the air flow stable. In other words make sure left and right get the same amound off air.
The top of the airbox is something they did not draw in 10min to.
The two D shaped holes are made at the side of the top so the air flow meat each other in the middle and spreads out
The same reason the trumpet's are bend towards the frond, spread the air flow

If you drill holes at the top there is a posebillety you cause a turbulence (two big air flows coming from the side and other small ones coming from top).
If you want to give it more air you could also make the D shapes O shapes ore nice oval to gain more air.
In short terms keeping two inlets the same size (think that is importend) as the air flow will hardly change at the lowest part.

I'm only saying
be cearfull drilling holes in the airbox.
I know Ndwedwe has good result with it. But (probably) he could have the same result making the D shape hols Round.
(Ndwedwe i mean no offence here, just throw a boll up to consider)


You can drill holes always later if you want (difficult to go back ones you have drilled them)

Its just some info guys, to think about
Cheers

Cheers for that Louis, glad you mentioned it.

I think I will then try without the snorkels and see. If it still needs more air then I will do what you suggested and make the D an O shape. If I am stuffed with too much air than at least I have another lid to use from my 3ma3.

It is just some info (my personal point a few) always open fore a discussion

I see a lot of guys experimenting in Dutch 50cc bikes with air boxes trying to get the best stady flow
If you see there experiments with different volumes/chaps/chambers its great to read.
They have 23HP from a 50cc


The bike sounds good, but perhaps a touch to rich (you use Q4 needle jets) the 320mains would probably be to rich with top air box mounted back
A big change you need to go down in mains.

But ofcours do it step by step

I have now tried it with no snorkels. The problem at 4500-6000 is a little worse than before but still much better than all of my previous set ups accept the one without the air box lid. I did however go all the way to the red line and that all seems rich too.

So basically what I have achieved is leaning the 4500-6000rpm range while making the 7000-12 000 rpm range richer.

I think this is a good thing. I will lower the needles by one clip which will put them in the lowest position, and try again. Hopefully that will clear the 4500-6000rpm spot up and then I can work on the top end and try to get that a bit leaner which should be no problem at all .

Luke 3MA wrote:I will lower the needles by one clip which will put them in the lowest position, and try again. Hopefully that will clear the 4500-6000rpm spot up and then I can work on the top end and try to get that a bit leaner which should be no problem at all .

you have smaller needle jets? and low needles? and big FAJ?

for me that is danger zone. as a road bike on the freeway you rarely go over 1/2 throttle.
i think you are being too fussy. like i said

Ndwedwe wrote:Just make it safe and ride it. Then take your time with small adjustments.

seizing a 3ma is way easier than jetting it.

The problem is I haven't managed to get it right and get the top end good, or at least gone into the top end. I am not the sort of person that settles for second best, So I will try my best to get it the best it can possibly be.

I understand that I have small needle jets big air jets and a low needle position, but I have huge mains and everything effects everything on the 3ma .

I know I will have to watch the temp at 1/4 and 1/2 throttle at higher revs with this set-up.

One question?

I might have missed something along the way, but here goes: Why have so many people gone the fixed air jet way and not just kept the VAJ? I know I have tried it because my VAJ was screwed and wasn't functioning at all.

Louis;

I think you posted a few pics/drawings of how the VAJ operates and what jets open at what rev ranges etc on the old forum. If you don't mind, could you please post it again. thanks

Luke 3MA wrote:One question?

I might have missed something along the way, but here goes: Why have so many people gone the fixed air jet way and not just kept the VAJ? I know I have tried it because my VAJ was screwed and wasn't functioning at all.

Reason to get rid of VAJ:
Simplicity, less clutter, less to go wrong, less likely to seize if a pipe comes off or cracks, easier diagnosis in future.

Reason to keep VAJ:
Eerm.....

Reason to keep VAJ:
Eerm.....

hahaha

You have got some good reasons there Ndwedwe.


I have modified the air box now and went for a little spin just before dark. It seems to be very close to, if not equal to what it was like without an air box.

Heres a pic:



I will do some very careful plug chops and see what the outcome is.

Also, I would just like to say now that I have the 320 mains in, the bike starts much easier when cold ????. The pilot jet, air screw and idle screw are suppose to control starting and 0/4 to 1/4 throttle. What funny carburation the 3ma has.

Thats precisly why I think the bike is running much better. It is getting more air and fuel, but because the main jets are so big it is not too lean at 1/4 to 1/2 throttle. I will do some accurate tests tomorrow to confirm.

If all is well with the plug chops than I think this will be the set-up I will keep, and I will have to be very careful with high revs and low throttle positions, until I know all is well.

cheers