Will DD shims help my Magna with the DynoJet kit?

[dc112675]

I posted this on another forum because unfortunately MOOT seems to be a little inactive.   I visit here 3-4 times a week but haven't had anything valuable to add to the discussion.  Nonetheless I want to ask your advice on this issue:

I have now completed all the major mods on my 95 magna, with the exception of one . . . installing shims. Why is this the case?

Am Ignorant? Am I chicken?

Yes.

I currently have Cobra drag pipes (installed by the PO) on it along with a DynoJet kit installed (by a mechanic). Looking at the DynoJet box, the 108 jets are missing, and there are (the OEM?) 102 jets in it. I also noticed the instructions call for drilling!?! I also installed a K&N air filter.

Being that this is my first street bike, I really can't compare it with anything else. For that reason, it's hard so say it has a flat spot, etc. To me it runs great. I've had it for 2 years and as long as it doesn't sit for too long (read: over a month) it runs like a champ.

So, here are my questions:
1. Has the installation of the 108's and subsequent drilling negatively affected it's performance? Is this reversible?

2. Will installing the DD Shims help? (I already have them with me).

3. While I have done several mods thus far (some that required re-wiring, drilling, welding, etc.) none of them involved touching the engine. Is that a doable task? How long might this take?

4. Are there any instructions/videos available to assist me in this endeavor? I do have a service manual but that is it. Any special tools required?

I have put this off for so long because I am afraid I might mess something up. I also am unsure if my current setup will even benefit from the shim kit. Do you have any wisdom, suggestions, etc. you can impart to me. I tend to ride pretty easy, so all out speed is not what I am looking for.  Personally I get fired up with good gas mileage (45 is the best I've gotten thus far). Thanks for your help, dc

[Greg Cothern]

DC, not sure what ya mean about MOOT forum not having much activity....
Dec 51 new topics, 536 new posts, and 14 new forum members, Jan 65 new topics, 636 new posts, and 12 new forum members, and so far in Feb 31 new topics, 292 new posts, and 8 new forum members.

OK onto your carbs, its hard to say if you need to shim the needles or not without more information.  You can add shims if it has a decernable mid-range flat spot (usually on a stock Magna its around 3000 rpm - 4200 rpms approx). 
The Dyna jet kit if installed according to their instructions, have your drill the diaphragm slides, this is only reversable by replacing them.  The jets and needles are simply swapped out.
There is also a very good write up on the tips and tricks page on the main MOOT site, http://www.magnaownersoftexas.com/tips.htm#A1.31 if I do say so myself hehehe. 
I can go you 1 better, I see your in the North Texas region, I host several wrench sessions and this is one of the most accomplished task during these sessions.  I am here to help, ya just gotta come down and join in on the fun at a wrench session and learn with us.  We have a few folks whom have done carbs a couple times 

[lragan]

I don't know about the current state of your carbs, but will testify to the effectiveness of the DD kit on my own '96.  I bought it used, and it already had the Cobra pipes installed.  Using the procedure Greg references, along with the instructions that came with the DD kit, took me, a not too swift mechanic, but generally handy with tools, about 4-5 hours round trip. 

And... it made a huge difference in two aspects of performance:

1) The backfiring that occured with engine braking went away.
2) The power curve improved substantially.  (I am a cautious rider myself, but I love the acceleration!)

It dropped my mileage from about 50 to about 46 mpg under similar conditions.

BTW, I am curious about the mods you have done that require welding.  What???

[TLRam1]

This link is not working any longer, maybe it's down.

Installing the DynoJet kit on a '94 Magna
by Archie (for some reason the included pics load up very slowly, even on a high speed connection)
on 5/29/2006

1) The backfiring that occured with engine braking went away.

Thats the part I like best! I don't want to loose that. If I leave my pilot adjustments as they are will this stay the same?

[lragan]

"Thats the part I like best! I don't want to loose that. If I leave my pilot adjustments as they are will this stay the same?"

If you like the noise and attention, it may be worth it to shorten the life of your engine, which is what, in my opinion, will happen. 

Backfiring is evidence of glowing carbon in the ignition chambers, which, I believe in this case, is the result of an engine running too lean.  Hard on plugs (easily replaced) and valves (not so easy.)

It is true that an engine can run efficiently on the "back side" of the optimum fuel/air mixture.  Piston aircraft engines are sometimes run in this mode (they sound rough, but run OK), but only if the valves and plugs have been replaced with platinum ones.  In this mode the aircraft engine is cooled with excess air instead of excess fuel, as is the normal "leaning" procedure to come to maximum exhaust gas temperature and richen the mixture just a bit to avoid burning piston heads as well.  Of course, our engine is not in an aircraft, does not run at constant rpm, and is liquid, not air, cooled. 

I believe, however, that the principles of combustion optimization vs engine life tradeoff carries over in general.

 

[drkngas]

 By reading this it sounds like my Magna could be the Anti-Magna.  Semi-loud Cobra Pipes, Cobra carb kit with drilled sliders, slight backfiring while decelerating and bad gas mileage. (hence the name "Drkngas")  Besides all that, WOW does it run great!!!

[dc112675]

BTW, I am curious about the mods you have done that require welding.  What???

I installed a fatbob LED brake light that I recessed under the rear fender.  In order to do so, I had to cut off about 2" off the metal support structure which is under the rear fender and welded some nuts on it.  I then bolted an 1/8" piece of steel that holds the brake light and the license plate on.  I am about to post pics (read: long time coming) which details this and the other mods. 

As for the comment about lack of inactivity, I apologize if that came across wrong.  While I visit the MOOT site often, I usually only read through "The Garage" section.  I owe my Magna half-life to you guys.  I set my sights on one after coming across the MOOT site over 2 years ago.  Since then you guys have helped me with gear, riding, maintenance, accessories, tuning, etc, etc, etc . . . I cannot thank you guys enough. 

I've wanted to meet you guys and thank you personally but unfortunately I am a little ways away.  I need to check my profile, as I used to live in Mansfield (although that was before I had the Magna) but I have been in Sweetwater, TX for about 2 1/2 years.  That puts me about 200 miles west of DFW.  Nonetheless you guys have been a huge help and I cannot thank you enough. 

I mentioned that I am done with all the major mods, and I just took pictures today of the [almost] finished product.  I have been wanting to do this for a long time, but kept putting it off until it was finished.  I know you are laughing, because we both know that it it is never done, and I do have another half dozen changes to make, but they are minor.  Again, if I wait til I am completely done then it will never happen.  So to Greg and all you other folks . . . thanks!

[TLRam1]

Sweetwater TX. Home of the Rattlesnake Roundup!

Went a couple of years ago, it was interesting. I would like to go back.

[Greg Cothern]

Sweetwater, TX is but a mere 40 miles (give or take) from the Central Region Coordinator for MOOT, Mr. Jimmy (manly spelled version) Glover.  He is very well versed in the Magna's and its workings....

[lragan]

While there are more MOOT members in N Texas, there are a substantial number in the Coastal and Central regions. 

Contrary to popular belief, the epicenter of Texas is not DFW.  I have even held a wrench session in Austin, and will host another as the need arises.  We didn't do much wrenchin, but we did enjoy the barbeque and data exchange.   

We could meet for lunch in LLano or Burnett some Saturday if you are game. 

[Curtis_Valk]

Contrary to popular belief, the epicenter of Texas is not DFW.  I have even held a wrench session in Austin, and will host another as the need arises.  We didn't do much wrenchin, but we did enjoy the barbeque and data exchange.   

That's what I love about this bunch.  I've seen Dallas and Houston folks ride to Texarkana to wrench, Houston and Texarkana folks wrenching in Dallas, and Dallas folks wrenching with the Houston bunch.  Folks rib me for riding long miles, but seriously the folks of MOOT are a riding bunch of fools!!!  (I mean that in the very best possible way) ha ha ha ha ha!!!!!

Curtis

[lragan]

Folks rib me for riding long miles, but seriously the folks of MOOT are a riding bunch of fools!!!  (I mean that in the very best possible way) ha ha ha ha ha!!!!!

Curtis

Well, I didn't buy and upgrade the bike to decorate the carport!! 

[Gloveberg]

DC, once again I appologize for not getting with you sooner on this like I told you I would.  Last year was not good for me and basically life just kinda got in the way of things.  I bitched for the longest time that I was the only MOOT guy out this way and here you are barely half an hour away from me but I never made the effort to come meet you.  That's my fault.  The bad part is that one of my favorite Sunday rides goes from Bronte towards Maryneal and then winds around to 71 and then towards Buffalo Gap and Abilene which means I pass practically right by Sweetwater.

I am far from a carb expert but after working with Greg on my carb bank I'm pretty sure I can do it again.  To me after you pull the carbs one time and really see what's going on and how they are laid out it's not nearly as intimidating.  As far as telling you if the shims would help or hurt I really can't say.  I personally went with the DD kit because it was a lot cheaper, simpler  and garnered much better reviews than the Cobra/DynoJet kit.

The weather is warming up nicely and soon it will be full time riding weather.  I work a 4-on, 4-off schedule which means I work weekends every other month (which is when most people are off).  However I promise I will get in touch with you and run up to Sweetwater so we can at least meet.  Again I do appologize but I'm sure you understand.  SOmetimes the best laid plans can be blown all to *$#@ 

Jimmy

[Gloveberg]

Sweetwater, TX is but a mere 40 miles (give or take) from the Central Region Coordinator for MOOT, Mr. Jimmie Glover.  He is very well versed in the Magna's and its workings....

Pssstt.....It's Jimmy.  Jimmie is the female spelling.

[Curtis_Valk]

HI JIMMY, how's your masculinity.............er, I mean, uhhhh howya doin???  ha ha ha ha ha

Curtis