[Nitori]

Hey all,

Not sure if this belongs in the jetting or general so pardon me if I'm posting up in the wrong spot.

I just picked up an '04 CRF100 a week or so ago, wasn't a real looker but it ran strong, and I wanted to give it the once-over and get it running in tip-top shape. You know, oil change, new spark plug, all the basics.

In the meantime we had some snow so it sat for a few days, but I pulled it out today and it was acting really strangely. Not at all like how it rode before.

At first I thought it was the spark arrester (it came without one and I bought an OEM one to replace it) messing up the jetting but I pulled it back off and the behavior persisted.

At first it would only kick over with the choke at the top position, and only just barely idle. The second you clicked the choke down a notch it would die. (And I waited at least a minute before clicking it down, multiple times) It smoked a little bit of light grayish smoke too, which I figured was the choke.

Then after a while it would kick over and idle with the choke in the middle, but the idle was still really weak and low.

I eventually got her running with the choke totally off and no need to intervene and rev it to keep it going, but the idle still seems really, really low and weak.

Do I just need to clean the crap out of the carb or is this indicative of something more sinister? I'm also a complete noob at carbs so explain any jetting changes like you would to a 4 year old.

Here's a quick vid of the idle:
https://www.youtube.com/watch?v=PgfSy_RUVZ8

I know these little thumpers valve click pretty loud too, but is that maybe a little too much?

[JimDirt]

Welcome to the site !!

The video does sound like there is some either valve ticking or Timing Chain slap or it could be because your listening on the Exhaust side which would tend to be a little noisier because the exhaust tends to give the engine a reflective echo , if it sounds the same on the shifter side of the engine , than i would guess its the timing chain or valve ticking , either of which should be adjustable , the engine idle sounds fine as far as RPM goes , does it backfire when you rev it or let off the throttle (while riding) ??

Does it bog at all when giving it throttle ??

If the bike came from the same basic elevation as where you are now or are riding it , then the jets "should" be ok , it would take a couple thousand feet elevation change to necessitate a jet change (like about 2000-3000 ft difference and even then only 1 size at most and a slight fuel screw adjustment)

Have you tried adjusting the fuel screw any to see if it improves the idle , or gets worse ?? (depending on the direction you turn it)

And yes you might get better or more specific replies in the CRF100 part of the forum , as the people that hang out in that forum are usually more familiar with the workings of the 100 specifically , since the majority of info/views here is usually pertaining to CRF450 and 250's , so the majority of "General Maintenance" forum views might be slacking for your specific bike