Jetting again
 

Im hoping someone on the forum can help me out with the jetting for my 2018 ec300. I have removed the smart carb as I just couldnt get it to run right with it. So I am back to the standard keihin. I have had the squish set and currently I have-
Slide- standard
Needle- NEDW
clip position- 1
main- 175
pilot- 40
air screw 1 1/2 turns

With the set up above it seems excessively smokey n rich at idle. Lots of pipe bang. So Im thinking I should either go down in pilot size or try another needle. I hae tried the jetting database but there doesnt seem to be a heap of info specific to this bike and year.. Im riding mostly from sea level to 500m above.

Hope someone can help. thanks in advance..
JC

Have you lowered the float height from stock?
That is almost my exact jetting, except I am back to a 42 pilot for winter and I am on clip position #2 with a 172 main. No knocking and clean crisp jetting all the way through the rev range mostly around sea level.
What is your squish set at and did they lower the compression? My stock head had way too much compression and no matter what I did with the jetting it knocked when hot.

My recommendation is:

go back to the 42 pilot jet, except temperature is over 92 F.
Replace the 175 with a 170 except temp is far below 50F.

Try the NECW in clip 3 and tune AS to your liking, normally about 2 turns out or more when riding in hot weather.

As Gasser Nate said, the float height is critical and set too high ex factory pushing the set-up towards the rich side. factories do that to be sure that you wont run it too lean.

Set it a tad lower, when tilting the bike from side to side it should nut spill fuel before reaching about 40 degrees lean angle.


edit: alternatively: JD-red in clip3, 178 main, 42 pilot AS 2 to 2,5 turns out. Works from 45 to 90 F.

Ok, I will try these recommendations and update with result. Thanks for the input..

Ok,
so I swapped the 40 pilot for a 42, swapped the main for a 170 and clip on 3rd position..
Result- It still seems too rich. Very smoky (but this could be the fuel as it is the very last bit of reserve Im using) A slight increase with the throttle and as it settles back down into idle there is heaps of pipe bang. I raised the clip to the 2nd position and it may be a little better. Pipe bang seemed to improve when the air screw was wound way out. Im talking probably 6 turns. What are your thoughts , should I try the 165 main or the 40 pilot??
thanks

JC

I fear there's something wrong, I just don't know what :(

6 full turns out? That's too far out and could fall out.

Pipe bang? Under load yeah?

Sounds like the needle isnt right, but you have it so try position 1.

Also don't change too much at once.

You have to keep thinking about the throttle position vs the jets controlling that section.

Hi,
I am very happy with this setup-
Slide- standard
Needle- NEDW
clip position- 2
main- 175
pilot- 42
air screw 2 turns out
I did spend some time getting the float level right.

i will check the float level again.. But I too am thinking something else may be wrong.

Checked for air leaks at reed cage, carb boot, or even non-sealing exhaust o-rings?

You could have an issue with the rhs crank seal if it's really smokey too.

Certainly something not 100%..

Given you have 2 carbs both showing poor running outside of the normal scope I think it's pointing at an issue being elsewhere.

Agreed, with that needle and jets you should be very close to a well running bike.

A crank seal could definitely explain a few things with me chasing my tail with the smart carb. Also had nathan at technology elevated a little confused as to what was happening as well. I will try to do a leak down test today and see how that goes. 1 of the exhaust orings was cactus so I ordered a new set earlier in the week and it should arrive shortly.
If I cant do the leak down test is there another way of testing it?? Fingers crossed it isnt the case seal..
thanks

JC

Whilst I wait for my new crank seals to arrive, can someone please advise me as to wether or not the crank seal should be flush with the lip of the case or recessed in behind it. Seems to be mixed opinions as some say if it is recessed in behind the lip the crank can be starved of oil. Also the manual says to tighten the crank nut to 40Nm however I am told elsewhere it should be 98Nm. Big difference in pressure..
I am unsure.
thanks

JC

40Nm is what the old workshop manual says.. BUT IS WAAAAY under spec for a thread of that size that is rotating. Remember LH thread too, so you'll need a torque wrench that goes backwards or go by feel.

Put the seal flush to just proud. The inner lip runs on a bushing so doesn't really matter 'where'. There is nothing stopping you driving the seal in too far though and doing so will cover the oil feed for the crank. Probably not the best idea.

Ok,
update. Ive replaced the right hand crank seal n there has been no change in the smokeiness coming out of the exhaust. I havent checked the reeds yet as it was starting fine so thought they must be fine. I will check them tonight. My money was on the crank seal but it seems that is not the problem.

I went through a river crossing a few weeks back which resulted in an expansion chamber full of water. I still dont know if it came through the exhaust or the intake. I would have thought if it came through the intake then I would not have been able to start the bike. From memory I think the bike stopped briefly on the other side of the river but after a couple of kicks I got it going again and I didnt think of it again until I discovered water in the expansion chamber days later. Would there be any chance that there is water in the big end or somewhere that is causing it to be sucked up into the chamber and giving me all the smoke??
thanks

JC

That bottom end is a pump. Not a good one but a pump never the less.

Any water would have been spat out in an instance.

Really hope you can nail this.

Did you do a leak down test? Seals aren?t the only places oil can be sucked in through. Poorly fitted gaskets, pin holes in crank cases... I have seen the lot!

I haven't done a leak test yet as I haven't been able to get my hands on a leak down tester. Hopefully get my hands on one over the weekend.
I pulled the reeds and they look brand new. I thought that the reeds may have been on upside down. Photo attached. Not 100% sure as I didnt take a heap of notice when I pulled the reeds out as I didnt realise these were offset slightly to the left for the carb boot intake, which is also offset to the left. Would this cause it to run rich??
I did do a compression test though. I hadnt done one on this bike before so havent got anything to compare the result to but all I could get was 80psi which seems like a very low reading.

I then had a look at the piston n rings through the exhaust port. There is heaps of blow by on the piston.Could it be possible that worn rings are causing my issue. Less than 40 hours on this bike since new. Bike generally starts first kick n i thought compression felt fine..

Did you have the bike warmed up before doing the compression test?

Also did you do it via holding throttle wide open?

I wouldn't have thought it'd start with only 80psi

No engine was cold. Throttle was closed..I will try it again tomorrow with the engine warmed up..
JC

Need to be wide open throttle when doing compression test.
And kick several times until the needle stops going up.

Ordered a leakdown tester on ebay. Should arrive early in the week. Just wanting to double check where I have to block off on this engine. Obvious points are the exhaust and intake. What about the powervalve, anywhere else??
Thanks
JC

OK,
I finally got the leakdown tester. !st place that failed once everything was blocked off and clamped up was the slave cylinder. I cant find a parts diagram for it anywhere. Does anyone know if there should be a gasket here?? Also would this likely be the source of my problem?? Could be other leaks however this seems to be the main leak at the moment.. It looks like there should be a rubber grommet however there is nothing.
thanks

JC

Eh?? What are you pressurising? There should be no connection between the crankcase and the gearbox where the slave lives, plus the gearbox has a breather.

Unless it is leaking through the right hand powervalve bearing into the gearbox...

Oh yeah, swine to try block off. But that would still just come out the gearbox breather.

I'm confusing engines, is it behind the kick lever?

Gearbox breather is at the top of the barrel above the right power valve cover confusingly! I?d say he has blocked off the hose and given the air no where to go. Yeah they can be a pig to block off!

Thanks gasser Nate and F5 for the reply. Yep, your correct I have blocked off that hose. (wrong thing to do??) I have also blocked off the intake and exhaust as well as the powervalve drain tube. I was under the impression that if I block all external outlets then it should be able to hold 5psi..

Can someone please advise me as to the correct procedure for a leakdown test. Pressure is input through spark plug hole in cylinder. I am pushing about 5 psi through it.
thanks in advance again.

Jc

You are doing it right, it is just that the air pressure is leaking around/through the right hand power valve bearing. Then into the gearbox via the breather passage. Might be worthwhile getting a new test bearing with rubber seals to pop in for testing only then pop the metal shielded one back in afterwards. They shouldn’t cost more than $5-10 from a bearing supplier. You can even leave that cover off while testing to spray some soapy water around the bearing to see if that is leaking.

thanks gasser nate.. Your a man of immense knowledge. My next question, can I push this bearing out from the left side if I remove the powervalve??

regards
JC

I have built a fair few motors in my time mate, thanks! Yeah you can tap it out from the other side.

For the first 10 mins most leaks you find are in your test rig.:D

Any updates on this thread?