finally on the road

[bchaffin]

Well after fighting carb issues for 2 months I am finally putting on the miles. I found out the dynojet stage 3 kit is over kill. I have put about 250 miles in the last week and no brake downs. I still have a flutter at high rpms, somewhere around 6 or 7000 rpms. My spark plugs are grey at the tip and there is a black ring around the first thread. Should I drop a jet size. I can't rember for sure what jets are in it now. I belive it has 128 on the outers and 138 on the inners. 2 odd things happened while riding yesterday.

1st I rode it to work and parked it uphill. After work I started it up and went to take of and it died. It would fire right up but then it would die when I gave it gas. It was doing this before when it had the bigger jets, I am guessing cause it was flooding. I slowly played with the throtle untill it finaly reved up then I had no problems.

2nd When I was heading home at the end of the night I was getting low on gas. I could still see there was some gas in the tank. I put it on res and headed for the gas tank. It then started running very rough. Was jerking and finaly died. I sit on the side of the road for a min. then it fired up. I rode it pretty hard to the gas station and filled it up. I t ran fine again after that.

Any thoughts on these issues.

[roadrider]

check the easy stuff first

check and replace your vacuum lines, they might look fine but they could have small cracks or they could be weak and suck flat.there should be two of them one for each petcock running from the intake to the petcock

[bchaffin]

I can see them pulse when it is running. I didn't even think about that being a problem.

[TopCatGr58]

Hey Chaffin,

As stated, bad vacuum lines can cause petcock flow problems, remember, they are vacuum controlled, loss or weak vacuum can keep the petcock valve from opening all the way, this can also lead to low fuel bowl levels at higher rpms which could be lack of power at that rpm...running low of fuel!?

Folks have reported as you found that the dynojet 3 IS overkill for most situations. Also, the staggered jetting...larger in the middle isn't really needed either, but if you have even plug color, then good for you.

As regards to the problems after work, you didn't mention whether you used the Choke/Enrichener when starting? Also, the float bowls may have been LOW again due to poor petcock flow, and then on the hill, even more trouble getting the fuel flowing from a low fuel level.

So....again, fixing the vacuum hoses "MAY" fix the other problems??
T.C.

[Larrym]

The Bitter Dregs...

2nd When I was heading home at the end of the night I was getting low on gas. I could still see there was some gas in the tank. I put it on res and headed for the gas tank. It then started running very rough. Was jerking and finaly died. I sit on the side of the road for a min. then it fired up. I rode it pretty hard to the gas station and filled it up. I t ran fine again after that.

Any thoughts on these issues.

bchaffin,

Chugga-CHUGG-Lurch-poppity-Chugg sounds like you either ran out of gas or at least got low enough with fuel for the carbs to starve. (Depends on whether you have any restrictions in the fuel lines between the tank and the carbs like inline filters or what-not...). An embarrassment for sure if any body saw a superbike running all spastic down the road. But there's more here.

Running out of gas is more than just an inconvenience. When the carbs no longer get a steady supply of fuel from the tank, the level of fuel in the bowls starts dropping. The cylinders run Leaner and Leaner as the BS34's pull the fuel from the bottom of the bowl. Leaner equals hot, hotter, and HOTTER as this happens.

Sure, all the cylinder parts (piston, rings, valves) should survive this temporary(???) HEAT WAVE. But sometimes the exhaust headers, especially the single walled aftermarket types, will get hot enough to change colors. From yellow (Perfect..) to Blue or even Bright purple (BAD...).

All it takes is to run low/out of gas just once. Long term results of repeatedly running out of gas? (Doom and gloom rant: deleted....)

If it was a lawnmower or weedwhacker I wouldn't give running-out-of-gas a second thought. Just another reason to take a "re-hydration break" on a hot day. On an air cooled superbike???

Happened to me ONCE. That was enough for me.

[planedick]

Vacuum

Some times when you let it sit for awhile with very little gas the engine heat warms the gas and the air in the tank and upon moving it the air suddenly cools because the air flowing over the tank and it causes a vacuum in the tank that the little vent can't keep up with. I had this problem several times until I figured it out. I can turn off the engine, take out the key and open the tank, replace the key and start the bike without stopping. Sovles the problem.

[bchaffin]

I do think I an still slightly over jetted.

As far as the bike stalling after work I had plenty of gas. It did it to me 2 days in a row. Once when parked on a hill once when not. I did not need to chock it, it fired right up but as soon as I took of it died like it was out of gas. Then all the sudden it acts like it finnaly gets gas and runs fine.

However yesterday on the way home it started running real rough. Thought I was not going to make it home. Weel I did eventually make it home and put it in the garage changed my clothes and came back out and more gas from the air filter. This is about the 3rd time I have fought this battle.

I do believe this time I an tearing it down and changing vaccume and fuel lines. I may call it good for the summer and start a little rebuild project.