My neighbors raptor is running horrible.

It has a rough idle but will idle. If you pickup the rpms, it spits and kicks randomly. Spits out black smoke.

I think its a bad CDI box.

This is what I have done so far. When I first looked at it could hardly get it to start. It got to the point where it wouldn't start at all.

1. Checked to see if the carbs unseated from the boots. They were. I re-seated them. No real change. I thought this was going to do it, but I guess it was seated enough for it to run OK.
2. Checked the plug. It was misfiring big time. You could see it intermitantly sparking when holding it against the frame while turning over. So I changed the plug. This helped alot. It would start and run now but rough. The plug seems to fire at regular intervals, however sometimes it sparks more intense than other times.
3. I checked the flywheel timining. Basically, I checked the TDC marks on the flywheel and watched the vavles. I compared to my perfect running 02 raptor. It appears to be identical. So,no slipped flywheel.
4. It has new fuel. They run racing fuel. I really don't think its a carb problem. It hasn't been rejetted or tampered with in at least 2 years. I have seen gummed up carbs on raptors...they don't run like this. Carb problems behave way different.
5. Checked and adjusted the valves. Intakes a little tight....but not enough to loose compression.

I think its ignition. I doubt if its the coil. I was going to try my 02 CDI box but it is incompatible with an 01.

It cuts out more at higher RPMs. I can't watch this on the plug cause it's only spinning at craking RPMs.

Do you concur that it is the CDI box?

 

I doubt it's the CDI. Usually, either a CDI works right, or goes up in smoke (literally, they will smell like burnt plastic) and doesn't work at all. I would look towards the stator or pickup coil.

 

I have seen CDIs act up before on other vechicle types like outboards. Also, Yamaha changed the design after 2001. Maybe because it was junk?

 

Yamaha changes the designs of electrical components from year to year, for reasons nobody except maybe yamaha themselves know. As an example, during the time the warrior was made, the CDI was changed 5 or 6 times, and none of those different designs are known to be unreliable or problematic. If you really think it's the CDI, I don't know what to tell you except to pick up one on ebay for cheap and see if it solves your problems.

I still think it's the stator or pickup coil, with almost all yamahas the pickup coils are known to fail, and cause intermittent operation like this. This is definitely a more common failure than a CDI box.

 

Well it wasn't the CDI box. There was no change except for more power. I opened up the carbs. The left float was really high. I adjusted it level. Both carbs were full of crud. I cleaned them out. The previous mechanic had the 175 in the left carb and the 170 in the right. I swapped them back. NO CHANGE!

I must say, at full thottle, this Raptor rocks. It runs perfect WOT, lifts the front end in thru 3rd. The problem is at low to half throttle. It cuts out falls on its face sputters. This must be fuel air related, not ignition, right?

It has 170/175 mains, #30 pilots. Open air box. Stock otherwise. This is about right I think.

Another thing, it has a GTYR pipe. It sounds like all the packing is gone. It is painfull on the ears to ride it is so loud. Could this be messing up the air fuel flow at low throttle?

 

You're probably jetted too rich in the midrange. Try raising the clip on the needles a notch.

 

The needles were full rich. The clip was all the way at the bottom. Plus, the washers and spacers were in the wrong order. I put it in the center position. This helped, but did not fix it totally. It's got #30 pilots. I think this is a bit rich for a stock motor. I will switch these to #25s. I think (hope) this will do it.

The mechanics at the shop that set this bike up must have been mentally challanged.

 

i have to agree it sounds like fuel, #30 sounds rich and that would cause that low end problem(s)

 

You said they're running race fuel. I think that confirms the notion that this bike is too rich. Try adjusting the pilots down to 25 and you might try raising the needle a clip again to the fourth notch. If the piston and cam are still stock, then I would suggest not running race fuel. Stock motors should stick to 93 or 94 octane.

 

Copy that. I think they run race fuel because they like the smell.