82 450E Jetting Help Needed - Don't match what's available?

[pete]

Hi all, I find myself in a bit of a quandry...

If you've seen my ignitor and/or rebuild thread you'll know I've been tackling spark issues due to a faulty ignitor, and today I got the Dynatek DS3-3C in and timed and I'm getting nice juicy sparks timed correctly, but she still won't fire and run.

I have K&N pods straight out of the box pre-oiled, and a custom made Tranzac exhaust that is going to be a bit freer than stock.

The guy at Tranzac didn't think I'd need to change the pilot jets but said I'd definitely need to change the mains (which I expected). I haven't changed them yet as I'm just trying to get it running well for the first time so I can get some heat into it and check the charging system etc.

Anyway, the symptoms are that it basically won't start. It did start on the choke when cold initially, but any touch of the throttle kills it, and it would only sort of idle for a few seconds before stalling. I was able to at least run the timing light on it to ensure the timing was good but that's about it.

I know it has fuel as taking the fuel bowl drain plug out lets fuel out, it's not empty.

I did the full and proper carb clean and have Mr Barr's O rings in there including intake boot O rings. Coincidentally I have new intake boots on their way from Boulevard Suzuki at the moment, but I believe that the boots I have are sealing ok, they're just not as supple as I think they should be.

I believe my float height is good as I checked and adjusted that as part of the rebuild.

Compression is good in both cylinders:



Spark is good in both cylinders (yay Dynatek).

Spark plugs aren't wet, and initially I was using plugs that had previously run rich, so I picked up some new plugs when I got the compression tester and they're gapped at 0.7mm straight out of the box, and no difference, and they're also not wet. NGK B8ES (stock plugs).

I have fiddled with the mixture screws and they were initially one turn out. They should have been two turns out but I think I must have counted wrong.

Either way, I tried them from half a turn out to 3.5 turns out and it still didn't start.

So the only thing I can think right now is that it's either too rich or too lean.

If it was too rich, it should at least fire up and idle, and I've seen too rich when I did the first start after the rebuild and I stupidly put rags over the carb intakes.

If it was too lean, I can understand that it wouldn't start. Or, if it started on choke only, that would be due to the the enrichening effect of the choke, but as soon as you touch the throttle it sucks more air which leans it out too much to combust again. Does that sound right?

So that's where it's at right now, so I'd like to get some confirmation that I'm on the right track that I need bigger pilot jets.

Now, onto my really confusing bit... the pilot jets I have match the N151.067 pilot jets in terms of shape and size as best I can tell, yet they're 17.5, and those jets only start at 30. The ones that have a 17.5 size are the VM22/210, but they have bleed holes whereas the ones I have don't.

What gives? Stock jets are supposed to be 17.5, so that matches up, but should I have bleed holes or not?

The Sudco PDF implies the VM22/210 are right for the OEM Suzuki carbs except for the GS1000/1100.

As for the main jets, once again there is confusion for me.

The ones I have measure and match N102.221 small round jets, but stock sizing is supposed to be 115 and I have 117.5 in there now. Not sure if this is a PO job or if the Aussie models had one size up fitted from the factory.

However, the Sudco PDF clearly states the GS450 uses N100.604 large round main jets, so more confusion.

Here's the best pic's I have of what I've got, sorry they're not spectacular I'm a bit photography challenged:



So, in a nutshell I intend to get 1 size up pilot jet and 3 size up mains as a starting point, but what jets do I order? This just makes no sense and I have no idea...

Can someone shed some light on this at all?

[Matchless]

Pete,
Just coming in from the side here and you may already know this.
These bikes can really only be started from cold on the choke, never touch the throttle until the choke is back in. She will be running at 2k-3k on full choke, then just slowly push the choke in as she heats up. When fully in you can use the throttle.
Good luck.

[pete]

Pete,
Just coming in from the side here and you may already know this.
These bikes can really only be started from cold on the choke, never touch the throttle until the choke is back in. She will be running at 2k-3k on full choke, then just slowly push the choke in as she heats up. When fully in you can use the throttle.
Good luck.

I hear what you're saying Andre, but in this case I don't think that's the issue.

When it ran briefly, it would only run on choke, but it would stall out after a short time, maybe half a minute or a minute.

Then it wouldn't start at all.

There were times when you could hear it trying to start, not sure how to describe it but you may know what I mean...

[pete]

You know in trying to be thorough about what info I provided in the initial post, I think I just put way too much there...

The key issue I'm having is that the pilots look like a N151.067, but there doesn't appear to be a 17.5 size jet in that range, and in fact the only range with a 17.5 in it is the VM22/210.

The other one is the mains which appear to be the N102.221 type, but what I've seen indicates my 450 should have the N100.604 type.

So, has someone has purchased Mikuni jets for these carb's before (surely yes?)? Which actual jets did you purchase?

[Matchless]

I hear what you're saying Andre, but in this case I don't think that's the issue.

When it ran briefly, it would only run on choke, but it would stall out after a short time, maybe half a minute or a minute.

Then it wouldn't start at all.

There were times when you could hear it trying to start, not sure how to describe it but you may know what I mean...

I recall my first start after doing the carbs together with a lot of other things and then the hard starting! Suddenly I started doubting things I was sure I had done properly!
Hope you get it sorted soon.

[pete]

I recall my first start after doing the carbs together with a lot of other things and then the hard starting! Suddenly I started doubting things I was sure I had done properly!
Hope you get it sorted soon.

Cheers Andre, me too!

The frustrating thing at the moment is that with my dodgy HEI setup it was sort of running and would at least idle (albeit poorly).

Now I think I'm in the clear with the spark situation but I can't get it to even idle... talk about frustration!

[landshark]

Are you using the fuel tank, or just a temporary set up?
I know you put a liner in your tank, did you block a breather or is the breather in fuel cap clear? (assuming it has one)
Have you pulled the drain plugs on the bowls to check there is enough fuel getting through?
My 1000 was hard to get going after the carb rebuild, i pulled the plugs and put a couple of drops of fuel into the cylinders to get some action and then it fired and ran.

[salty_monk]

With the stock pilot jets I would expect you to have to open up the screws 3-3.5 turns out if it's anything like the four cyinders I've run with pipe & pods.....

If that's not enough then you need to go up a size on the pilots.

[pete]

Are you using the fuel tank, or just a temporary set up?
I know you put a liner in your tank, did you block a breather or is the breather in fuel cap clear? (assuming it has one)
Have you pulled the drain plugs on the bowls to check there is enough fuel getting through?
My 1000 was hard to get going after the carb rebuild, i pulled the plugs and put a couple of drops of fuel into the cylinders to get some action and then it fired and ran.

Just a temporary one hanging off the 'bars for the moment. Haven't done anything with the tank aside from line it as I need to paint it anyway and the fuel tap is currently on back order from Japan.

Pulled the drain plug and plenty of fuel in there... it did fire up briefly initially so I know it had fuel from that as well, I just don't think it's sucking enough through the pilot circuit and is just far too lean.

With the stock pilot jets I would expect you to have to open up the screws 3-3.5 turns out if it's anything like the four cyinders I've run with pipe & pods.....

If that's not enough then you need to go up a size on the pilots.

I'm pretty sure that's what I'm facing Dan, I went as far as 3.5 turns out and it was still a no go...

[pete]

So as well as starting this thread I also emailed the guys at www.mikunioz.com thinking they may have some idea, but no reply as yet.

There's also a place in South Australia www.iwt.com.au that have all the jets for $8.50 each. Not sure if that's a good price or not, but looking at Jets R Us, Chaparral Motorsports, Z1, etc. leads me to believe I'd be better spending $8.50 each here as I think shipping from the US will kill any price benefit.

Anyway, I did some further Google searching in my lunch break and I think I found the answer on another bike forum:

http://forum.motorcycle-usa.com/default.aspx?f=18&m=472209

I have a 1980 Suzuki GS 450 that I have been working on for the past year. I know every single thing about those carbs. They are Mikuni BS 34 (Constant Velocity type) carbs. The factory jetting is 17.5 pilot and 115 main. My bike has K&N pods (air box totally removed) and a pair of universal glass pack mufflers. Before, the bike was so lean that it wouldn't even start on choke. Then I began the painful process of jetting.
Note: The types of jets needed are as follows:
The pilot jet is a mikuni VM22
The main is a "Mikuni Small round Main"
Chapparal Motorsports sells jets for a crazy good price.
Check out this link: http://motorcycle.chaparral-racing.c...w=mikuni%20jet

Now, on My Suzuki with pod filters and hi-flow mufflers, My pilot jet is size 37.5 and my main is a 135 and STILL is running a teeny tiny bit too lean. I will probably need a 40 or 42.5 pilot to get the fuel mixture perfect. But remember, the factory air box is super restrictive. The pods and jetting make a huge difference in power. My GS450 has a 41 tooth rear sproket and 16 front (slightly more highway and less acceleration) and get this... It will do 0-60 in a little less than 7 seconds!!! It may be a 450 but it has incredible power because of the insane ammount of air and fuel its getting. If you have any questions about a GS 450 let me know. I havent rebuilt the engine yet (will do top end rebuild this winter) but if you have any questions about the carbs/electrical/brakes/tires/final drive... let me know! I might be able to help you out.
-Vinny

Now I don't know if the guy really knows as much as he claims, but I figure he's at least got the right type of jets in there, so it looks like the VM22/210 for the pilots and N102/221 Small Round for the mains.

I'm thinking I should get 2 x 20 pilots and 2 x 22.5 pilots as well as 2 x 125 and 2 x 127.5 mains as a starting point.

That gives me 1 and 2 sizes up on the pilots and 3 and 4 sizes up on the mains.

Does that seem like a fair call? I know it's all stab in the dark right now but I've gotta start somewhere...

[tthayer]

Try taking the pods off and covering the intake with a thick towel or rag. You really want to restrict the airflow if you haven't increased the pilot jets yet.

[pete]

I didn't do that yesterday, but I did do that on my first ever start after the rebuilt and actually made it far too restrictive so it was far too rich.

Something else that just dawned on me is that is starting cranking a bit easier when it stopped actually being able to run.

If the rings have started to bed in, how likely is that to contribute to this?

At the moment I'm thinking buy the jets (75% sure I have to change pilots regardless, 100% sure I have to change mains) and see what happens.

[Big Rich]

Pete, I know it may sound odd, but is your idle set too low? I've had that happen to me before as well. Just turn the idle screw in a few times and see what happens.

Good luck man. You'll get it straightened out.

[salty_monk]

In my experience on the 4cyl's you wont really notice the 2.5 step jetting changes (without an AF meter setup anyway).

I would halve your expense & just go for the 5 ups.

On my 1980 1000G running K&N in the airbox with V&H 4:1 I had to go up to 122.5 or 125, neither made any noticeable difference over the other. That uses a stock 115 as well on a 34mm carb which is why I mention it.
When I ran it with pods I went up to a 132.5 from memory, maybe a 135. The 1000G dynojet kit also has a small bush that you install in the fixed airjet to make it much smaller, makes it about the same size as the ones on the 1100's (16v). I also went up one size on the pilots as I had them although I had just enough adjustment on the stock ones too.

I have a bunch of main jets & even a spare set of Dynojet needles for the 1000g if it's the same carb body, I could probably send them all to you (express with tracking - 6 days) for about $32 (US) & you could mess about with it all & then send them back when finished. We'd just figure out a fair price for what parts you kept.

Good luck with it.

[pete]

Pete, I know it may sound odd, but is your idle set too low? I've had that happen to me before as well. Just turn the idle screw in a few times and see what happens.

Good luck man. You'll get it straightened out.

I played with the idle, both wound it up and wound it out so it was off completely, didn't seem to make a difference... worth a thought though for sure

In my experience on the 4cyl's you wont really notice the 2.5 step jetting changes (without an AF meter setup anyway).

I would halve your expense & just go for the 5 ups.

On my 1980 1000G running K&N in the airbox with V&H 4:1 I had to go up to 122.5 or 125, neither made any noticeable difference over the other. That uses a stock 115 as well on a 34mm carb which is why I mention it.
When I ran it with pods I went up to a 132.5 from memory, maybe a 135. The 1000G dynojet kit also has a small bush that you install in the fixed airjet to make it much smaller, makes it about the same size as the ones on the 1100's (16v). I also went up one size on the pilots as I had them although I had just enough adjustment on the stock ones too.

I have a bunch of main jets & even a spare set of Dynojet needles for the 1000g if it's the same carb body, I could probably send them all to you (express with tracking - 6 days) for about $32 (US) & you could mess about with it all & then send them back when finished. We'd just figure out a fair price for what parts you kept.

Good luck with it.

Awesome Dan, that's the sort of thing that will help for sure, and it seems we're on a similar wave length.

I was thinking today that instead of paying $68 for a bunch of jets that were a stab in the dark I should go straight to the 22.5 pilots and 127.5 mains given it's better to be a bit rich than a bit lean, so it seems my thought was not so silly after all

I also recall someone else on here with a 450 talking about getting a set of needles from Rapidray and selling off the two he doesn't use (Ray only sells sets of 4), so that could be a good option for needles as well, but for the moment I've put mine one down to raise them which should richen them up a bit.

I will definitely keep your offer in mind, however I think I should be able to get the pilots and mains this week which means in theory I could give it another blast next weekend.

If only Dynojet made a stage 3 kit for the 450's I'd be laughin'... but stage 1 is all they do...

I'm also waiting on new intake boots from Boulevard Suzuki but I'm not sure if they'll get here by then or not.

Any other thoughts keep them coming, and I will update when I get some progress made...