Won't rev. Hard to start

[Yamahablue]

Hi guys. I'm new and just got this bike last week. It's got a FMF fatty gold pipe and core 2 silencer. I pulled the carb down and cleaned it good. I can get the bike to start and somewhat idle after several kicks. I can feather the throttle and get it to rev but it bogs when I hit the throttle wide open. I also noticed it looked like it was spraying fuel out the intake side of the carb when I would hit the throttle. Also while it's idling I've tried to get on and take off figuring it may need to be "blown out" but it just loses power and dies.

Is there a way to check the size of the jet?

Any help would be appreciated guys and gals.
Thanks in advance!

 

[piezzi]

Welcome to BF.

Start with the basics:

Compression test (s/b ~120lbs or above)
Leak down test to see if your motor is leaking/sucking air
Clean & re-oil air filter
Put in new spark plug
fresh gas (mixed 32:1 if pre-mixing)
disconnect TORS (see DIY section of BlasterForum.com)
might as well change case oil while you're at it.

The jets are each stamped with the size. It's very small and tough to see, and sometimes the stamp is on the top and sometimes on the side.

Once it's running better for you, you can then do a "plug chop" (see DIY section) to verify your current jetting is in the ballpark and then fine-tune your jetting.

Good luck!

 

[BlasterIan]

If its blowing fuel out at the engine side of the carb then you have a airleak and thats your problem!

 

[Blaaster]

If it is spitting fuel from the intake when the throttle is opened, maybe the reeds are not seating or are worn.

Why did you pull the carb off and clean in the first place. Did the problem exist prior to your cleaning or after you cleaned it?

 

[Yamahablue]

I cleaned the carb because the bike had been sitting for a while. I work on small engines on the side and this is my first "large" 2-stroke engine I get to "play with". Just good practice is to clean the carb instead of introducing foreign matter into the engine. Thus creating more problems. Guy said it was running perfect when he parked it. So idk?

Tors is disconnected
I'm premixing 24:1 per the previous owner. Guy at the bike shop said the was fine.

 

[Blaaster]

24:1 is a bit thick, nearly all the guys on here run 32:1. I am different my conditions require me to use 25:1 and I run castor.

Pull the reed block out and have an inspection. With your experience you should have reassembled the carb correctly but it would be an idea to double check.

Was there any crap in the carb when you cleaned it?

 

[Yamahablue]

I've pulled the carb apart and put it bac together about 4 or 5 times for a couple different reasons so I know it's together correctly. I'm not sure why the guy said 24:1 but that how I mixed it. I'm going to have to call and ask why so I could maybe mix a little less. I didnt notice anything in the carb but the bowl gasket was missing a corner so I replaced it. I keep reading about reeds and I haven't gotten to that yet.

On a side note maybe related to the reeds, while I was giving throttle the bike would spike up wide open (it sounded like) and I would have to cut the ignition off (by way of a switch) to stop it. But I could recrank it and it would idle normal, or cut the switch back on while the engine was coming down and it would idle normal again.

???

 

[Yamahablue]

Guy said the crank kit recommended it for the new bearings and it's jetted wit a 280 (he thinks) because of the k&n and the exhaust. But he said it is rejetted

 

[back again]

sounds to me u have a massive airleak betting its the reed cage and boot.just from the high rev and idle you described

 

[Blaaster]

Most probably an air leak, get them reeds out check them, if they are ok put them back with new gaskets and do a leak down test to see if there are any more leaky seals.

Point of interest, is the plastic slosh baffle fitted around the main jet in the carb bowl.
If it is missing and a vibration sets in, the motor can run uncontrollably as the fuel can get air mixed with it.

Your motor will run fine at 32:1. As I stated before I use 25:1 because of my circumstances.

At 24:1 you run the risk of plug fouling and excess black spooge coming from the exhaust joints.

If you are jetted correctly and riding extremely hard, and getting to the correct operating temp, then the higher oil ratios can add just a little more HP.

 

[Yamahablue]

Like I said, the guy said the crank kit suggested the 24:1 ratio so I'll stick with that for a while. I am going to pull the reed cage as soon as I can to give them a one over. I do remember the slosh baffle being there. I pulled the jet out while I was cleaning to check for anything in there.
I also have a spacer I pulled off of another jug I have extra. What's the ruling on that? Any pros/cons for it?

 

[Blaaster]

I like to think that my spacer gives me some more low/mid power but there are those that will condemn that. One big pro is that it allows you to be able to fit a larger carb as it give more clearance.

At 24:1, you need to richen up the main jet some as you are leaning the pre mix, may need to go up a size or even two.

 

[Yamahablue]

Conclusion:
I pulled my reed cage out and found a broken petal on one side. I had a couple extra so I replaced them AND put in the spacer I had. Cranked it and what do you know? It runs like a champ! Will give kudos and more info tomorrow.

 

[Braaaptor]

Glad you got it fixed! BTW, 32:1 pre-mix with just about any good 2-stroke oil will do you just fine and won't hurt the engine. I'm a career small engine mechanic myself and have seen just about every way there is to tear up a small 2-stroke engine. 32:1 Mix won't hurt your engine as long as the jetting is close. Lean out the oil mix a little and you'll see a little more usable power and less smoke. (As well as a cleaner plug, of course). My .02.

 

[Blaaster]

32:1 is good, but if you still choose to run the 24:1 slip in a bigger jet to be on the safe side.

As you should know it is better to err on the rich side, it costs a lot less!