Problems with 421 cub

[TeamRealtreeHD]

Went out riding today and had some problems. Bike was spitting and sputtering on the hills. Badly.

 

I am running 162 mains and 52 pilots with a 421 cub. 35mm PWK's. CEL on 3rd clip. Air screws 1 turn out.

 

It's still a little lean on the bottom, throwing 55's in it. Might go to 58's and work down.

 

But I believe it might be something else. Stator coil, flywheel, spark plug caps. Possibly the floats need more adjusting (currently at 16mm)

 

My question is, could it be something else? I plan to test these things. After a few weeks off. I'm all tuned out. All wrenched out.

 

What would the bike act like if it was a bad stator coil or flywheel? Spark Plug Caps?

 

It was spitting and sputtering, wanting to shut down but still kicking and barely going. Tough to xplain the sounds when your on it, but that's the best I could do. A fellow member was there and saw/heard it. Maybe he can chime in.

 

None of the electrical stuff I mentioned ever went bad, and was never replaced on this motor. Maybe it's that.

 

I heard many say that they had electrical problems that they thought was jetting. It made them go insane. Just like it is with me.

 

I just need input from guys who have been down this road. Or someone to throw this thing off a cliff

[AKheathen]

start simple- maaintenance. new plugs- what do the old ones look like? air filter(s) clean carbs/fuel.

[firebanshee]

When in doubt put new spark plug caps on it

[SAVAGE420]

Again... ?

[MAICK]

check your cylinder base nuts. i had mine come loose and broke two studs, a few weeks ago. when mine did it, it was running good and all of a sudden it died and then i could barely keep it running.

[TeamRealtreeHD]

start simple- maaintenance. new plugs- what do the old ones look like? air filter(s) clean carbs/fuel.

 

Very solid advice... however, I can assure you there isn't many guys on this site that do more routine maintenance than me. Which is what makes this so frustrating.

 

Carbs come off every week and so do air filters for cleaning. Been doing it this way for years. Pods make it an easy task.

 

I think it may be electrical.

 

Thanks for the advice. I'd say that's where I'd start too, but I know it's not that.

[TeamRealtreeHD]

Again... ?

 

Shit goes bad on a bike Savage. Plain and simple.

 

So yes, I am having problems again. A streak of bad luck on my end.

Edited July 11, 2010 by TeamRealtreeHD

[TeamRealtreeHD]

I must add that I checked all of the bolts on the cool head, and well as or flywheel. And askithe cylinder. I also checked the intakes.

 

I did a compression test and both sides are dead on where they were when I built the motor. Not one PSI difference. It's well built for sure. 165 PSI on both sides. Dead on, the same. That's always a sigh of relief of course.

 

Just looking for someone who may have has a bad stator, or plug caps, and wondering how it acted?

 

How about a bad CDI?

[Paul M]

X2 on the spark plug caps

[TeamRealtreeHD]

The needles worked very well for this motor with 33mm PWK's. Possibly the 35's they don't.

 

It only does it under a very large load on the motor.

 

On flat ground, it pulls through the gears good. But once there is a heavy load on the motor, it sputters and cuts out. The pilot circuit is still a little lean from what I can tell.

[VegasJeff]

I had the exact same setup as you and I had the sputtering problem as well and it turned out to be the pickup gap. I built a 4 mil cub for a buddy of mine and it sputtered real bad and it turned out to be the CDI,I plugged mine in and it was fine.

[sleeper06]

I think your rich,I have jetted many cubs,some came in at 162,50 but they have ranged as low as 150 mains,45 pilots at sea level,every motor is diffrent

[TeamRealtreeHD]

I think your rich,I have jetted many cubs,some came in at 162,50 but they have ranged as low as 150 mains,45 pilots at sea level,every motor is diffrent

 

Here's the deal. I was running 33mm PWK's with this motor and had them jetted at 158 mains, 48 pilot with 1.5 out on air screws. CEL on middle clip.

 

I switched to PWK 35mm's a week ago, and have had problems ever since.

 

I am thinking something went, and it was just a coincedence it was when I got the new carbs.

 

52 pilots are acting like they aren't even close. Pipes are getting very hot. And there is no smoke at all coming out of the pipes, and no oil on the silencers. It still has a bog off idle.

 

My pickup is set at 18 thousandths (.018").

[TeamRealtreeHD]

I had the exact same setup as you and I had the sputtering problem as well and it turned out to be the pickup gap. I built a 4 mil cub for a buddy of mine and it sputtered real bad and it turned out to be the CDI,I plugged mine in and it was fine.

 

Pickup is currently at .018". I am swapping out a CDI off another running bike this week. I'll check that.

[AKheathen]

Pickup is currently at .018". I am swapping out a CDI off another running bike this week. I'll check that.

mark your throttle and see exactly where it happens. if it's been doin it singe you put the carbs on, it's somethin around there. either the wires under the carbs, airleak, or in the carbs. if you can just barely gas it before it hapens, like 1/8'th og, then it may be your needles or air jet, mabey even the needle jet. can you roll-on the throttle more and run good?