Hey, thanks for the reply again. Just to clarify, in your dyna airbox mod did you replace the jets too? Also did you completely block the frame ducts and drill the cover?
Also I have no idea why my pic uploaded that way but if you click on it twice, once to open and once to turn it upright you can get a better look.

Thanks again!

 

one more thing, what did you do to the snorkels?

 

I am not running mine as a streetfighter, so my snorkels are still hooked up and working. I did rejet, as well as a ton of other mods. You can read my for sale post "time to say goodbye" for the full specs.
A dynajet stage 2 kit comes with a box of main and pilot jets, new needles, drill bits to mod the carb slides, and information on how to mod the airbox. Further box and carb mods make it the stage 7 kit.

 

Interesting thread. I picked up a naked parts bike because I needed a frame and title for my primary bike (long story). I plan on getting rid of all the rest of the parts because a) it has clearly been put down, b) someone has done hinky wiring patches all over it, and c) it isn't in particularly good shape (but it has a lot of good parts). After I bought it, having test ridden it around town and having it run OK, I trailered it to my shop and then decided to ride it home a few days later, just for fun. Exact same symptoms. I could not get it above 60mph and it was a struggle to keep it there. I haven't spent too much time worrying about it since my plan is to get rid of everything but the frame anyway, but now I'm wondering if that is the only issue.

Hmm. Now I have another project.

 

Well its getting better with the mods you suggested. This is what I've done:
1. Completely blocked frame inlets
2. Completely blocked snorkels
3. Drilled 24 1/2" holes on top of airbox

I can tell its still getting too much air at speed so will need to deflect air from under tank as well. Im thinking ill just stuff a wash cloth under there.
Im including a pic because I'm curious if anyone knows if the fuel filter should have more fuel than shows. You can see the line at about 3/4 full. This is while running.

Also, above the 'T' behind the carbs theres a tube. Its between the 1st and 2nd carb if your looking from behind. There is nowhere this goes, its just an open line. Is this normal?

Thanks again for everyones help. Especially Drakito as the mods are working!

 

Not sure from your description, but there should be a tee with a hose between each pair of carbs (the one your describing should have a matching one on the other two carbs). These are the float bowl vents. They should have a short piece of hose 2"-3" long. The ends should be open. But these are on the airbox side not behind. If you have tubes on the back side you may have California spec carbs. Post a picture. There are a few extra hoses on the Cali spec carbs. Those ones need to be capped if you are not running Cali spec pollution system.


We still have not gotten verification that you checked the fuel flow items that we suggested earlier. Seems you are on your own path...and the results aren't what you expected. The whole too much air issue is a crap shoot IMO. Maybe you should go back and look at what was suggested...just a thought. Many here have spent a lot of time troubleshooting these issues...we do have some experience with these type of problems. Sorry I'm a little short, but you asked questions and then did what "you" thought was right. It's quite frustrating when suggestions are made and none are followed up on.


There is a method to troubleshooting that is normally followed. You still have no idea whether you have proper fuel flow in the system. If it is fuel starvation as I suggested in an earlier post, playing with air flow could result in a catastrophic failure. If your running lean when your testing all of these air flow mods, don't be surprised if you hole a piston.


So maybe you should take the time to test the things that were suggested earlier.


Have you tested for fuel flow from the tank?
Have you tested the fuel pump?
Do you have a good fuel filter on the bike?
Have you verified the size of the main jets? Needles? Needle position?
Have you checked the float shut off levels?
Have you checked the fuel distribution at the carbs? (Plugged tee or side pipes)
Have you checked to see there is no dirt in the carbs and jets?
Add Vacuum leaks to the equation if you have open pipes on the back side of the carbs...

 

BTW, you do understand that if you restrict air flow when running lean it will seem to improve.

 

Ok. Dennis, I appreciate your advice and the laws of troubleshooting. I don't want to be the rogue that "does his own thing". In the 4th and 5th post here I described what I had done and you acknowledged it.
Quote:
Originally Posted by shemwatson77 View Post
The other thing that interested me from your reply was the petcock comment. What in it would fail? Its not vacuumed, I replaced the internal filter and o ring, and cleaned it out.
(You
"Yes another suggestion that it looks like you have addressed. "

So Im no expert mechanic, I should have addressed that up front. I don't know how nor do I have the tool to check the readings of the electrical aspects of the fuel pump. It is getting fuel, i hear it click click click to suck the fuel in. Thats all I know right now which is why i asked about the (new) fuel filter I posted in a pic.
Im limited on funds and have a grand into already after the initial $500 and just having the rear bearings/seals etc replaced on the wheel and getting a tire.
I don't know if I have the ability to pull the carbs out. I was hoping to find a reason for this bogging without all that but understand that it may be a deeper problem than too much air.
The thing is I've read a lot of posts here as I described early on and Drakito has backed up that taking all the bodywork off is going to have problems of ram air. Thats why I'm trying to follow his advice as he has done this on a previous bike.
It seems to be working and if it was lean to begin with wouldn't it have difficulty starting or idling? It only has the "issue" at thrust.

Nonetheless, I truly do appreciate the sound advice and thoughtful replies from individuals that obviously love this motorcycle and want to help others, be it novices, to get the most from their bike.
Thank you,

Shem

 

Would really like to see a picture of your carbs and specifically the pipe you described on the back of the carbs.


Some simple things you could do:


Take the fuel line from the tank to the fuel pump off. Get a container and open the petcock and see what sort of flow you get. The old petcocks can restrict flow if not in the full open position.


Take the pump off and test it for flow. There is a test method in the manual that gives a rate based on how much fluid is moved in a certain period of time.


Some more complicated things you can do:


In earlier posts we asked you what jets are in the carbs. The advice Drakito gave you on air box mods related to the Stage II kit and he said "I did rejet, as well as a ton of other mods." You specifically asked him about jetting. It is very important to know what jets are in your carbs if you want to be sure you are not running lean.


This means you really need to take the carbs off and look at everything. It's important to know. If you haven't taken the carbs apart then you are pissing up a rope here...you don't know what you have, whether they are clean or not, tuned properly, what jets are in there...a multitude of things you need to know. These bikes are very finicky when the carbs are dirty or not set up properly.


I have 7 (seven) F1's. Each one went through a process that should be followed on any bike you do not know the history on, or a bike that has been sitting for any length of time.


Drain all the fluids and replace with new. Check the fuel tank for rust. Remove rust if present. Clean the petcock and filter. Check the fuel lines to insure there isn't crud or debri inside of them. Remove the carbs and soak them overnight. Take all of the components off of the carbs (including pilot screws) so that only the bodies and float bowls remain. Mark down jet sizes for future reference. Spray carb cleaner through all of the passages and make sure fluid flows through each side of every passage. Insure that the jets are clean (pilot jets can be difficult to get clean there are specific methods for cleaning them). Set the pilot screws to 2 1/4 to 2 1/2 turns. Reassemble the carbs and bench set sync.


Inspect the intake boots for cracks and damage. Replace if needed. Install carbs.


Install new battery and start bike up.


95% of running issues are carb related on these bikes. The carbs are sensitive to dirt. If you were told the carbs were just cleaned don't believe it. That's a common sales pitch because it is what is usually wrong with these bike. I've never bought one that was supposed to have clean carbs that actually did. On one the carbs were full of rust. Most are dirty. Not only that, if the carbs were cleaned they usually end up with dirty pilot circuits (because no one seems to understand how to clean them) or they are improperly adjusted. I never trust anything until I get in there and verify it.


Why? Because if you don't know how can you troubleshoot a problem? If the carbs are dirty or adjusted wrong, or jetted wrong, anything you do will be a waste of time. You have to have a good baseline to work from. It starts from the ground up not from the top down.


In your case I would be very worried that I might damage the engine...running lean...reving it out to try and solve a bogging problem. Like I said before, you will burn a hole in a piston or multiple pistons. This is not a joke...do a search. Lean burning is bad. Very bad. We tune to the rich side when we don't know actual fuel/air mix...because fouled plugs are easy to fix.

 

You need to do a search on how CV carburetors work.


Starting and idle are separate circuits in the carbs.


Starting is facilitated by the "enrichers" which allow extra fuel into the carbs via the choke lever.


Idle is controlled by the pilot circuit. Fuel is delivered via the pilot jets and air via the pilot screw setting.


Very little fuel is required for starting and idle.


All of this is completely separate from the main fuel circuit which takes over at about 1/8th throttle.


The problem you are having is in the main circuit or fuel flow volume from your description. A bike will start and idle and still be lean in overall fuel/air mix.