Rpm drops on idle

[Jim Cook]

Originally Posted by swehollow

So here is an update. I tried needles and jets in different combination. It runs like a Beast but has the same issue With idling. When it got realllly warm after hours of Riding it would Idle.

I Think i Will look in too the squish clearence. See whats going on there.

Lets say i have 2mm+ and i have someone machine it down to 1ish, what is this compression ratio you Guys are talking about? I Guess Any Good machine shop should know all the necessary steps?

My RB Designs head mod measures (using the "mashed solder" method) at 1.2 mm between the piston and the head.

[(F5)]

If you machine the. Squish to the right figure the compression will be silly too high; unusable. So you need to machine the chamber. That's why RB is actually good value. I did my own but took like 6 cuts and measures. Read my thread on it if you care to. Love how it runs now.

[swehollow]

Alright. Only problem is That i m nowhere Close to the big us and a

Is it optimal to have the compression End up in the same ball park as it started Before the shaving of the head/

[Jakobi]

Your compression will be set to your conditions and the power characteristics you want. Higher comp will require higher octane fuels, and promote strong snappy low end power at the expense of rpm; and vice versa.

[motopsycho87]

It will push the compression ratio through the roof, if you remove 1mm of head, using pi*r^2*h

r = 7.2cm/2 = 3.6cm
h = 0.1cm

pi*3.6^2*0.1 = 4.073cc required to maintain compression ratio.

It is worth using the oil method (fill cylinder with oil at TDC to the spark plug thread) to ascertain your current compression ratio, then you can ask the machinist to raise or lower it to your specifications. (I machined mine to 13:1).

I've had the exact same idling issues, and finally narrowed it down to bad right hand crank bearings which can be seen very clearly on the attached pic (look at the staining inside the RH crank).

My symptoms were, power felt 'fluttery' at low revs, would sometimes drop to below idle and be hard to recover. After idling for a while would eventually bog and die. First start of the day, or any starting after sitting for a while would result in incredible amounts of smoke.

[32:1]

I had the same brain destroying problem....

very frustrating indeed, jetting and messing around for weeks. Mine after all was a faulty fuel valve !
Even float height settings wont cure a worn valve....

Sometimes it would idle fine, yes for 2>3 minutes waiting for friends on trail, next section it would either idle fine, or for a while, then load up and drop off within seconds, a good clear out and it would 50% of the time idle again


Mine is a 2006 ec200
45pilot
#6 slide
R1369n in 3rd
180 main



Regards

Chris

[32:1]

Originally Posted by Jakobi

The the G diameter needles are what this year likes, you could consider trying an N3EG/N3CG as well. It'll be a pretty aggressive setup though with a strong mid range transition, or for a smoother deal possibly an NEDG/NECG (suzuki).

When I say try though, thats exactly what it is. From there you'd need to gauge how you think the bike is performing and make any changes required to address lean areas/richness.

Jakobi, could you give info on those codes please, how do they stand with the old r1468n etc or the CCL etc

Ive played with needles for a while and have recently found a N1369n works good, my stock N1ec ran like a dump truck, did try the NOZ# versions and was running a NOZG in 2nd, now r1369n in middle with a bit better mid>top power.