Cheap HP mod? Mikuni VM flow optimizer

[pcnsd]

Has anyone seen or tried these? Claim of 1.5 - 2 HP per 100 cc's on 2 strokes. On my 430 that would be 6-8 HP improvement in the low/mid range. That is huge! and only $30.00 but...... I've been a fool before too, so... What do you think?

See link:
http://www.thunderproducts.com/u_f_o.htm

Regards,
PC

 

[flyarmy]

It is a neat idea if it works? The price seems right for an experiment. That would be a hugh increase in HP for my XC430. Do I need anymore HP or just a smoother delivery? Quick..someone find out and let us know. Mike

 

[Motosportz]

On my 430 that would be 6-8 HP improvement in the low/mid range

I'll eat my moto socks after a long day on the trail if that will add 8 hp.

 

[pcnsd]

I'll eat my moto socks after a long day on the trail if that will add 8 hp.

I have paid much more to receive much less and if a guy got only half of claimed, that would be money well spent. I found a patent for this device in my research. The flow data at the end of the document is very interesting.

http://www.google.com/patents?vid=USPAT6082711

PC

 

[Motosportz]

I have paid much more to receive much less and if a guy got only half of claimed, that would be money well spent. I found a patent for this device in my research. The flow data at the end of the document is very interesting.

http://www.google.com/patents?vid=USPAT6082711

PC

Oh, i believe it could work but 8 hp is not going to happen IMHO.

 

[flyarmy]

Great detective work on finding the patent. Now we need to see if anyone has used one and how did they like it. It seems simple enough in design.

 

[Leftcoast leftkicker]

Essentially it makes a flat slide? On another post we had a member make a "wing" similar to FMF's "Power Now" with great results. I contacted both FMF & Boyeson, neither had any interest on modifying for round slide Mikunis though.

 

[Motosportz]

Essentially it makes a flat slide?

Not really just smooths the flow across the bottom of the slide.

 

[pcnsd]

Bought one, arrives in 1 week

I spoke with Lonn (designer) He advises that the 1.5 - 2 hp per 100cc is based on multicarb, multicylinder 2 strokes (Snowmobiles with greater port swept area). A 70-80's single cylinder 2 stroke can expect .75 -1 HP per 100cc after jetting changes. Almost all increase is in low to mid range. Most comments reflect the perception of instant throttle response and bottom end drive. He suggested that the "Dial-a-jet" is a good companion as it targets top end performance.

After setup, tuning and some track time, I'll post my impressions and advise if it was money well spent.

Regards,
PC

 

[Motosportz]

He suggested that the "Dial-a-jet" is a good companion as it targets top end performance.

I don't know if they have changed the design or not but ran one of those on my 99 WR250 Husky. Could never get it to work well and it was fragile and troublesome. I like the idea but the implementation was not good. This was many years ago so I'm guessing it is more sorted now.

Edit: Just looked at it...

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

Looks like the same plastic crap I ran. There were several install issues and it passed dirt through the little air filter that is on it. I'm not being rude just letting you know before you get into something that was disappointing IMHO. I think i still have that thing some where. If I find it I'll offer it up to someone who wants to try it. Like I said, I liked the idea.

This is one of the parts that gave me trouble...

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

Leaked a lot of dirt, kept falling off, just was not well designed.

 

[pcnsd]

I did not purchase and I am not testing the Dial-a jet. Although, thank you for your feed back on it as I was considering it as a later possible option. I will test only the UFO product and provide feed back on my impressions of its perceived benefits, if any. I don't have a dyno, so if I can't feel a difference (a real difference) I will so advise.

I once spent $140.00 on a Rad valve and it sure looked pretty, but didn't deliver the on the promise of power despite a lot of jetting trials. IMHO if you can't feel a difference when you twist the throttle, it's just like it's not there, regardless of what a dyno may tell.

Regards,
PC

 

[Motosportz]

IMHO if you can't feel a difference when you twist the throttle, it's just like it's not there, regardless of what a dyno may tell.

Regards,
PC

Yep.

Took the plunge on the first Power Now / carb wing. I thought it worked very well on my YZF250. Some things do in fact work.

 

[hawaii-rider]

I built a wing for my Ten Fins, posted the build here and the results were very impressive.
I will NOT take it off my XC500.

Smoother power and very nice and VERY noticeable enhancement in throttle response and beefed up the bottom end quite well.

I have built 3 of the intake wings to date, and each delivered.

Im sold.

They work for me.

HR

:usa:

 

[pcnsd]

Ultimate Flow Optimizer Arrives

The UFO was waiting in the mail when I got home, So I checked it out. It comes with the UFO, plastic drill guide, one small installation screw (which I promptly lost) and a installation guide. I have a spare 3.5 throttle valve so I did some test fitting. The quality of the part itself is not bad. It is an injection molded part, looks like either acetal or nylon. It fits to the 3.5 TV like you would hope.
I am posting some pics of the kit. The installation guide calls for a single screw mounting. I will likely go with two mount screws that I glue in place with a suitable threadlocker. I will install to the slide tomorrow during lunch and fit to the carb when I get home. Maybe test ride if it's not too late and get an idea of where the jetting is.

Link to installation guide:
http://http://www.xs650.org.au/UFO%20Installation%20Guide.pdf

Regards,
PC

 

[pcnsd]

UFO installation and jetting, Part 1

I followed the directions in the installation guide with only minor issues to note. The installation guide shows the plastic drill position guide mounted reverse of the actual. Assuming you check position relationships before drilling, this won't get ya, if not look out.
The other issue I found with the drill guide is that it is just a bit too large to center the through hole drill (9/64") accurately, but I manage to fuddle through without incident. The installation guide suggest using a 9/32" drill as the countersink for the slide hole. The issue with this is that common countersunk heads are either 82 or 90 degrees and the common twist drill tip is 118 or 135 degrees. Not a good fit in my opinion. I used a 90 countersink that matched my screws. I choose to through drill the two screw bosses that matched my chosen layout. I tapped for 6-32 threads and installed the UFO to the slide. So far so good.

When I arrived home I attempted to install the modified slide to the carb, but the throttle cable end would not clear the UFO underside. I used a die grinder to remove the two offending screw bosses and retried. No go, I had to loosen the UFO plate to fit the cable then re-tighten. From there the install guide states to replace the pilot jet with one 50% smaller. For me this was a #20. I installed, finished the carb assembly and started the bike. It was clear almost as soon as it started that it was too rich at idle (Way!) I took it for a short ride after warm up and confirmed that there was a VERY rich spot between 0-1/8 throttle. Mikuni PJ's only go down to a 15. I installed one and adjusted the air screw to 3 turns out. Same deal, still too rich. That is where I am going to leave it until tomorrow.
My plan for tomorrow is to take one of my older duplicate PJ's and solder it close. My gut feel is that it will still be too rich, but before I go to drilling a bleed hole in the needle jet hood, I want to be sure there is no other choice.
As for the sought after HP increase, it is too early to say. Until the jetting is sorted all my mind seems to fall on is the dead spot off idle.

Regards
PC

 

[Leftcoast leftkicker]

Paul- maybe it has the effect of richening the slide?

 

[Motosportz]

Drop the needle one.

- Having a screw in the throttle opening that could potentially fall out and go through the motor kinda freaks me out. This is a high vibration area.

 

[pcnsd]

Installation and jetting, Part 2

I'll take this opportunity to answer the questions above.
All jetting issues are expected and directions to resolve are in the installation guide I posted previously.

The screw(s) can not fall into the carb throat. They are installed from above and are held captive by the spring plate that also holds the Jet needle in position. If the screw(s) back out and the UFO plate comes loose, it is held by jet needle and can not be inducted into the motor, although my guess is that it would be a "bad thing" in the general scheme of things during a race. I will use ample thread locker when I work my way to a final configuration.

Today's efforts:
I installed a PJ that had been soldered close and was greeted with a motor that would idle..... a little too fast. I took it for a ride after a short warm up and noted that there is indeed a crispness in throttle response that was not there before, but it is too early to say it is worth it yet. I'll summarize a final opinion later.
As for the fast idle, (unadjustable with the idle screw) I pull the carb and discovered the the UFO plate was holding the throttle valve slightly open and I have spend the evening scrapping the UFO plate where it is touching with some minor success (I have worked about half the distance out, about .020"). Once I get it so I can move the motor idle to the point of shutoff (I'll mention that I don't like a dirt bike the will idle more than about 10 seconds without some personal attention.) I will try some roll ons and full throttle runs on the pavement. I like to test on the pavement initially because the better traction available makes it easier to feel improvement or the lack thereof.

Regards,
PC

 

[rajobigguy]

Very nice write up. I appreciate you're attention to detail.

 

[Motosportz]

Good stuff. Thanks for the info.

K