Rejetting experiments begin

[jave101]

Yeah makes sense thanks for that.
I'll have to find a plug that fits the drain plug to do the fuel level measurement.
Today I bench synced them with a piece of paper in the butterflies so they can't be too far off.

Perhaps the main jet is too large I jumped up from 110 to 130. I'm not going to buy anymore jets until the k&n pods get here, no point wasting anymore money just yet.

Also the previous owner damaged the heads of both the pilot jets when he removed them. I've read there is supposed to be a rubber plug or some thing that goes over the pilot jet? I don't have anything that goes into the pilot jet hole except the jet itself. Am I getting confused between carbs or just totally way off?

[pete]

Not sure on the pilot jet rubber plugs, you'd need to check the parts fiche. Given the sizes for your jets they're not the same as my carbs and they're the only ones I've seen in person to date (except the little Ducati's Weber but that don't count).

I've seen people take a spare drain plug, drill the centre out, and braise/weld in a nipple to attach some clear fuel hose. For the short amount of time it would get used, I imagine JB Weld would do the job. Actually I just gave myself an idea... although I just used a piece of cardboard, marked the measurements, sat it on the gasket surface and checked the float heights that way.

I'd highly recommend some carb sync gauges though. They can be had for a reasonable price too. I ended up with the Morgan Carbtune from the UK courtesy of a Chrissy present last year.

[Steve]

Also the previous owner damaged the heads of both the pilot jets when he removed them. I've read there is supposed to be a rubber plug or some thing that goes over the pilot jet? I don't have anything that goes into the pilot jet hole except the jet itself. Am I getting confused between carbs or just totally way off?

Yep, there should be a rubber plug.



If you look just above the rubber plug, just before you get to the pilot jet, you will see an angled passage that goes down to just above the main jet. THAT is where the pilot jet is supposed to get it's fuel. Without the rubber plug, the pilot jet will also be able to suck fuel from the area where the plug is supposed to be. That really isn't a problem, though. Where the problem lies, is when you get above the pilot circuit and get into the needle and main circuits. The main jet will limit the flow of gas into the needle circuit once the needle is pretty much up all the way and not doing any metering of its own. Without the rubber plug, gas will also be able to go up that hole, then down the angled passage, bypassing the main jet, and have you chasing your tail trying to get the jetting right.

.

[jave101]

Ok well look like ill be taking the carbs off again haha. Will the damaged slots on the top of the pilot jets cause any problems? I don't think they would as the jet hole itself is perfectly fine but I've heard people say replace any damaged jets.

Also there is another jet in that diagram of yours that looks like its for the idle circuit if I'm not mistaken, on the intake side of the carb on the left hand side. I'm quite sure my carbs don't have anything in there.

Looking at different carb stripping tutorials I think I have BS34ss carbs. Is this diagram for my specific carbs? I have seen many different internally structured carbs that are all called BS34's.

Thanks for the help.

[Steve]

Also there is another jet in that diagram of yours that looks like its for the idle circuit if I'm not mistaken, on the intake side of the carb on the left hand side. I'm quite sure my carbs don't have anything in there.

If you are talking about the jet in the intake throat at about the 8 o'clock position, and is connected with dashed lines to the side view of the carb, yes, you should have jets in there, they are the pilot AIR jets that work with the pilot FUEL jets that are just above the rubber plugs. Together, they make the pilot MIXTURE which is then regulated by the idle MIXTURE screws that are shown on top of the outlet of the carb.

I can't say for sure what is supposed to be in there, though. My only information says that they are supposed to be "1.4-1.5". The rest of my list shows that carbs with similar numbers are all VM carbs. All the BS carbs have numbers like 150, 160, 170, etc., so I don't know if yours are supposed to be "140-150". Later 450s had 135 and 145 jets, so I would think that's about right.
.

[jave101]

I'm starting to think this might be a coil issue, I've got carbon fouled plugs and very weak spark. Left hand ran with right hand spark plug lead pulled off but not the other way around.
So I swapped the coils over and right hand ran with left hand pulled but not the other way round.

So I'm thinking maybe dud coils, anyone know where I might get genuine ones or good quality ones as the coils that are on the bike a cheap eBay ones.

[pete]

Could be a simple as the spark plug caps if they're still the dodgy old ones.

Brand new should be less than $10 each for NGK ones.

Strip a quarter inch or so of the plug lead off and screw them on and if that's the issue you'll be good as gold.

[jave101]

I tried that too, no good. They were new ones that came with the coils too