HAS ANY OF YOU TRIED THE DIAL-A-JET FROM THUNDER PRODUCTS. AND IF SO THEN HOW DID IT PREFORM AND WOULD YOU RECOMMEND IT?

ONION wrote on 12/31/69 at 16:00:08:


I think lancer might have messed with a dial-a-jet - the idea seems odd to me that one must create a lean condition so the dial-a-jet can fix it.  ???

LANCER wrote on 12/31/69 at 16:00:08:

Oh I understand the idea is to not create a lean condition in the end - what bothered me was the dial-a-jet documentation where it stated you may need to create one so the dial-a-jet can fix it

here's a rather interesting read on subject, paragraph #7 is what pushes me toward the snake oil side  

"Dial-A-Jet is an add fuel only device. You cannot add fuel to an engine that is running rich or has an adequate fuel supply and hope to gain horsepower. You must create a lean condition so that Dial-A-Jet has a window of opportunity to function."

http://www.thunderproducts.com/dial_a_jet_techpaper.htm  

I have spent a good bit of time on the phone with the guy who makes  the Dial-a-jet and I think you are misunderstanding what he is trying to say in that paragraph.  
The lean condition referred to is that small area of jetting that lies between a jet that would be too rich and the next size down that will work properly under most conditions.  If there were a jet size that was half way between the other  2 jets then that would be the better jet to use.  But since there is no "half-step" jet available, that slight lean condition that may be created at times while riding is filled by the dial-a-jet.
He is NOT SUGGESTING that a SIGNIFICANT LEAN CONDITION BE CREATED... not in the least  If you look at a printout from a dyno run where you just jetted/tuned your bike, you will find that there are peaks and valleys where there may be a some slight rich or lean areas along the rpm range.  To remove all of the lean areas you need to go to the next larger jet sizes, which will result in NO LEAN  AREAS but will leave some areas right on and others a little rich.  He is saying to go to the jet sizes just on the lower side of the curve, which give some areas just right and some slightly lean ... and it is those slightly lean areas that are filled in by the dial-a-jet.

This is a long way from running a bike so lean that engine damage would result if the dial-a-jet stopped working.

Reelthing wrote on 12/31/69 at 16:00:08:



You are absolutely correct.  I went back and read through the material again and he does suggest a 3-4 jet size toward the lean for maximum function, and that is described as "slightly lean".  I did not remember seeing that before nor him saying anyting about it during our discussions.   Now I need to talk to him again about this because it is, as you said, a big step into the lean territory  while it is called "slightly lean"... that seems more than slightly lean to me..

Thank you for your persistance and helping me to see the error of my ways in this.  Truth must prevail if we are to advance.

Hey Lancer
Would you know how much a dial-a-jet kit is for a Keihin FCR41.

Also do you know anything about Factory Pro HDJ emulsion tubes again for FCR41

Clive W  

Hey Lancer,again

What is the fixing system for the jet part of the Dial-a-Jet, Is it more drilling and tapping ?

Thanks.

Clive W  

I like the idea of this thing. "Denco" Dennis Dean ran them on his wicked Kawasakis. The Savage is about 5-10 jet sizes lean (145 stock up to 152,155,157 w/ open pipe) depending on the exhaust setup. Greg talked me out of it before I started messing w/ my stock bike. His point is it was just as easy to drop the bowl and rejet. (Of course anyone that disassembles their engine each winter might ) Added complexity = reduced reliability
I was attracted to the tunablity feature which would be good for finding the right jet size. One might install one and adjust it for awhile and get a good idea of what is required for the the proper jet size and try that. If It ran better w/o the DAJ them just swap it for a stock bowl and sell the complete DAJ to the next guy or keep it if your carb needed '1/2' jet to be right on.