Main Jet Guidance Needed!

A

Arkwright

Two Stroke
Hi guys

I recently rejetted my bike as reccommended by the supplier of my new DNA pod filters, but it appears to be running way too rich. Lots of smoke out of both pipes, strong smell of fuel and a small amount of unburnt fuel dripping out of pipes.

I was told to fit 150 mains, which I did, but now looking for advice on what to try next. Being presently unemployed, I'm not in a position to buy lots of different sizes to be able to experiment and also not in a position to take it to a mechanic to sort out.

Any pointers would really help...

Thanks in advance...
 
BlueJ

BlueJ

Blue Haired Freak
Jets are cheap. Maybe $3 a piece. If you are running free-flowing pipes, you'd probably want to go with 145's at most. You also need to adjust your mixture screws. I agree with DrLapo - Jenks guide (google is your friend) is a good start.
 
monty

monty

Street Tracker
A. I will have a look. I may have a pair of 128 mains that came with a free flow element. If I can find them, they are yours. I have never fitted them as I did not fit the filter.

Monty
 
BlueJ

BlueJ

Blue Haired Freak
Well even at $7.50 a piece... my point was that the OP talked about being on a budget, and a new set of jets is like filling up the tank a couple of times, not like getting new exhaust or carbs or whatnot.
 
mikenva

mikenva

Rocker
Make sure you have the fuel line hooked up to the bottom line on the carbs if you had them off.If they are hooked to the top tee it will flood bad.140 to 145 mains should do it
 
A

Arkwright

Two Stroke
mikenva said:
Make sure you have the fuel line hooked up to the bottom line on the carbs if you had them off.If they are hooked to the top tee it will flood bad.140 to 145 mains should do it
Click to expand...

Not sure what you mean on this one Mike...

Didn't realise there was more than one place it could be hooked up
 
J

JimmyR

Street Tracker
I have K+N filters on my bike with some Dominator mufflers - pretty much the same as Preds I think. I had changed to 145 mains but it was still a bit rich. Today I went down to 140s on the advice of BC and they seem perfect. I ride at close to sea level. The bike runs beautifully and blows no smoke or smell of unburnt fuel. The top half of the throttle range seems even better now than it did with 145s.
 
A

Arkwright

Two Stroke
JimmyR said:
I have K+N filters on my bike with some Dominator mufflers - pretty much the same as Preds I think. I had changed to 145 mains but it was still a bit rich. Today I went down to 140s on the advice of BC and they seem perfect. I ride at close to sea level. The bike runs beautifully and blows no smoke or smell of unburnt fuel. The top half of the throttle range seems even better now than it did with 145s.
Click to expand...

Well I'm at a loss now...

By all accounts, the DNA filters I have are the best free flowing filters available, which in theory means I would need to at least on 140's or a little higher.

Yesterday I fitted 135 mains and it made very little difference at all. Bike is still way too rich. No unburnt fuel as I had with the 150's, but lots of smoke.
 
D

drlapo

Hooligan
smoke!! something is amiss as a too rich main jet shoud not produce smoke until the throttle is more than 3/4 open and even then it would be minimal
are your floats stuck? is there dirt in the float needle?
 
bonZa

bonZa

Street Tracker
Arkwright said:
Well I'm at a loss now...

By all accounts, the DNA filters I have are the best free flowing filters available, which in theory means I would need to at least on 140's or a little higher.

Yesterday I fitted 135 mains and it made very little difference at all. Bike is still way too rich. No unburnt fuel as I had with the 150's, but lots of smoke.
Click to expand...

are you talking black smoke? and are your spark plugs all sooted up?
need to get to basics

what size pilot jets do you have? and how many turns out are the idle mixture screws set at?

then there are things like float height, which should be ok unless someone has fiddled with it

the jenks guide is a very good starting point and is what I used to set mine up with and with good results. do a search and you should be able to find it in pdf form
 
A

Arkwright

Two Stroke
Ok guys here's the setup...

2004 865cc T100

Presently 135 mains, 40 pilots, one needle shim, mixture screw 2.5 turns out.

No airbox, AI disabled, straight through Burgess style exhausts.

The smoke isn't soot black, more of a dark grey and there is a smell of unburnt fuel.

Floats haven't been touched.

I went with 135's on the advice given in Jenks guide.

Not much else I can tell ya really...
 
D

drlapo

Hooligan
something is wrong and its not the jet size
when does the engine emit the smoke and odor?
idle, 1/4 throttle, 1/2 throttle, 3/4 etc?
i suspect float level or a stuck open float needle
take it all apart and reassemble carefully
 
A

Arkwright

Two Stroke
drlapo said:
something is wrong and its not the jet size
when does the engine emit the smoke and odor?
idle, 1/4 throttle, 1/2 throttle, 3/4 etc?
i suspect float level or a stuck open float needle
take it all apart and reassemble carefully
Click to expand...

I'll take a short video later this morning and post it on this thread.
 
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