Bike is down, for a while

[Carl La Fong]

I've noticed that the bike hasn't been running all that great lately. I thought it might be carburetion. The other day it conked out and wouldn't start. No fuel. After checking the pump and finding it to be OK I cranked it and felt the pump push rod with my thumb. Nothing. The cam went flat. Upon further investigation, I found that the Boy Genius™ installed the push rod backwards. A billet cam needs a brass tipped push rod because a steel one will ruin the lobe. I had the brass end against the pump. Doh!! So, a new cam is on it's way from Comp. I'm also replacing the timing cover since I suspect that's where a mystery oil leak has been coming from. Bummer, but that's the way it goes. Shoulda stuck with the electric pump

[Orlando606VetteTrike]

Sorry to hear John. I'm still battling idle/carb settings too after this upgrade of mine.

[Imzz4]

You'll probably end up doing other stuff to it when you get it apart. Are you going back to electric ?

[Carl La Fong]

No electric. The Race Pump works super good. The failure was operator error. I'm still amazed that I did something that dumb and careless. Also that the cam lasted as long as it did
If anyone needs a 385 horse camshaft, I have a good one. Just doesn't have a fuel pump lobe. No problem for you Holley Red guys

[SQ4MN]

John I got a great ride planned for the 19th that you will not want to miss, its a surprise but you especially will be really upset if you miss it. GET A CAM AND FIX THE BIKE OR BORROW A BIKE.

[Carl La Fong]

Shouldn't be a problem. I should have the cam next week. One day to put it back together and we'll be golden

[Carl La Fong]

After much trial and, even more, error, it was the fuel pump. I have a mechanical pump. I wrote about it in my blog. I tore it apart and found nothing obviously wrong with it. Yet, it would not pump. I contacted the manufacturer and he said it can't be the pump. It has to be vapor lock or a bad regulator. I told him the engine is cold and the temperature is a balmy 80 degrees. Nothing comes out of the pump outlet so it can't be the regulator and it sure as hell isn't vapor lock. Finally, in desperation, I re plumbed my old electric pump in. It promptly sprung a leak. Now, I'm about ready to set fire to it and buy a Vespa. I dug out one of those little electronic fuel pumps that I had in my parts stash. I hooked it up and, voila, it fired instantly. I have ordered a rebuild kit for the mechanical pump. I feel it is a good setup and I just had an unfortunate, unavoidable failure.

[SQ4MN]

So it is not a worn out cam? Did you replace the cam? Does it use a regular chevy mechanical fuel pump like can be bought at AutoZone? I have used a Holley for 8 years with no problems and a mechanical one on the V8 Chopper for 5 years with no trouble. My Chopper came with no fuel pump back in 2008. It just gravity fed. It was fine up to 125 mph but then would need more gas so Stan started adding the mechanical pumps.

[2crzy]

A good electric fuel pump with a regulator and a return line back to the tank and you will never have a problem with vapor lock or not enough fuel. Those mechanical pumps will vapor lock on a hot day and then your screwed sitting until it cools off. Nothing worse than sitting in traffic and it quits.

[hogv8]

A good electric fuel pump with a regulator and a return line back to the tank and you will never have a problem with vapor lock or not enough fuel. Those mechanical pumps will vapor lock on a hot day and then your screwed sitting until it cools off. Nothing worse than sitting in traffic and it quits.

I don't understand the return line to the tank ?? With my Holley Red set up there is of course a fuel line from the tank petcock thru a filter to the fuel pump and from the fuel pump to the carb . I don't see the necessity for a regulator with the Holley Red but that's just me .

[2crzy]

The regulator keeps a steady constant pressure and flow and the remainder of the fuel gets circulated back to the tank so you don't get vapor lock. You only need 7 to 10 PSI and most of the pumps put out way more and especially in volume. It is hard on seals in your carb and also hard on the pump with dead end pressure. More susceptible for the carb to start leaking without you knowing and going up in flames. Not a Cool Ride!!

[hogv8]

The regulator keeps a steady constant pressure and flow and the remainder of the fuel gets circulated back to the tank so you don't get vapor lock. You only need 7 to 10 PSI and most of the pumps put out way more and especially in volume. It is hard on seals in your carb and also hard on the pump with dead end pressure. More susceptible for the carb to start leaking without you knowing and going up in flames. Not a Cool Ride!!

I still don't understand how fuel gets circulated back to the gas tank . I understand all about fuel pressure the regulator and I have used one before but are you saying if the fuel pressure regulator is set at let's say 5 lbs. and the fuel pump is putting out 10 lbs. , 5 lbs. gets circulated back to the gas tank ? I know I'm thick headed and I don't mean any disrespect but I just don't understand .
By the way , a Holley Red puts out 5 to 9 lbs .

[2crzy]

Yes that's what it means, not just the pressure but the extra volume. There is a return bung on the bottom of the tank close to your pet cock to run another line back to it. The Fuel injected bikes have them as well. I had to change the whole fuel rail system and add return line on my LS bike because it was vapor locking very bad. Problem solved when I put a return line that looped all of the injectors back to the regulator and then bypassed to the tank.

[2crzy]

Oh most regulators only have an inlet and outlet on them for carburetors but you can get the ones with the bypass, they are what I use on all my performance stuff.
No chance of vapor lock at all.

[Bhilldw0111]

The regulator keeps a steady constant pressure and flow and the remainder of the fuel gets circulated back to the tank so you don't get vapor lock. You only need 7 to 10 PSI and most of the pumps put out way more and especially in volume. It is hard on seals in your carb and also hard on the pump with dead end pressure. More susceptible for the carb to start leaking without you knowing and going up in flames. Not a Cool Ride!!

I still don't understand how fuel gets circulated back to the gas tank . I understand all about fuel pressure the regulator and I have used one before but are you saying if the fuel pressure regulator is set at let's say 5 lbs. and the fuel pump is putting out 10 lbs. , 5 lbs. gets circulated back to the gas tank ? I know I'm thick headed and I don't mean any disrespect but I just don't understand .
By the way , a Holley Red puts out 5 to 9 lbs .

Shouldn't the needle and seat in the carb stop a flow of 5 to 9 psi without being damaged. I don't know of any other seals anywhere else that would be effected. Am I wrong?

[2crzy]

You are absolutely right. But when you start running too much pressure than the needle valves get wore very quickly and start pushing fuel past them. I have seen fuel flow right out of the top of the carb before when they screw up and dump fuel everywhere. Not good on a hot bike in the summer.

[Carl La Fong]

Glad to see you guys have solved my problem
As I stated, vapor lock was not my issue. It never has been. I ran with an electric pump for the first 3 years that I owned the bike and the rest with the mechanical pump. I've ridden in, nearly, 120 degree weather at 220 degree engine temps and never had vapor lock. I've been in contact with the pump designer and manufacturer. He says I should have used a deadhead regulator with an idle bleed return line. I have the parts on order. I have to figure out how to run the return line. Hopefully, I can tee it into the feed line since I have no provisions for a return

[randy burkey]

Carl, Could you "T" it in the fuel line just after the petcock?? thus returning extra fuel to the inlet tube? It seems to me that the "extra " fuel being delivered under pressure should override the gravity fuel from the tank and any backpressure derived should exit the tank vent??

[2crzy]

You should have a return on your tank. If not tee into the cross over line.

[Bhilldw0111]

You should have a return on your tank. If not tee into the cross over line.

My tank is off right now and there in only one hole for the petcock, but good idea about the t to the crossover.

[2crzy]

I thought all the tanks had 2 or 3 holes in them.
What year is your bike?

[Bhilldw0111]

I thought all the tanks had 2 or 3 holes in them.
What year is your bike?

I have an 02 and a 98, They do have 3 holes but two are used for crossover and one is petcock

[Bhilldw0111]

I thought all the tanks had 2 or 3 holes in them.
What year is your bike?

I have an 02 and a 98, They do have 3 holes but two are used for crossover and one is petcock

Oh, and maybe if we are gonna get much farther off subject we should start a new thread, sorry Carl, if we Hyjacked yours.

[Carl La Fong]

Hijack away. No sweat
I have my problem sorted out, I think