Sidecar Bonneville Land Speed Elite 50 build

[Revolutionary]

Got everything squared away working til midnight last night and Speedweek got flooded and was officially cancelled this morning. Bummer

At least now I have time for some proper tuning. So far it seems to like 50/125 jetting.

[Revolutionary]

[Revolutionary]

A few notes:

Rules required I have a way to shut off the fuel supply without removing hands from handlebars. The best options I could come up with were to either use a choke cable to push a fuel petcock closed or use a solenoid. I used a nitrous fuel solenoid and rewired the high/low headlight dimmer switch so it would turn on/off the fuel supply.

For the nitrous, I have an "arm" toggle switch by the solenoid and rewired the horn button as the momentary switch to activate the nitrous. I currently have an .008" jet in there. I have run a LOT of nitrous in the past, but never on a 2 stroke and never through reed valves, so I am being very cautious about it. As Bonneville is several thousand feet above sea level, my goal was only to run enough nitrous to bring the power back in line with sea level or slightly better. I ran around the block a few times and sprayed it and I could just barely notice the difference. That is what I am looking for at this point. Once a little more testing is done, I may try to fatten up the main carb jet and give a little more n2o jet.

The cyl heat temp gauge works great. I had ordered a tach over a week ago and it had not arrived. Hopefully it will show up today and I can get that installed.

I will pull the sidecar back off this week so I can take the scooter to a dyno within the next few weeks. Got to dial this thing in.

[Revolutionary]

Killing time before the next event (World Finals) at Bonneville at the end of September and looking for more power. A couple of things have me scratching my head.

1) Engine does not want to turn over 9000rpm. My thoughts are the port configuration and pipe are the limiting factors here. which leads me to..

2) I have been doing quite a bit of reading (the A. Graham Bell book is pretty good though old) and it makes sense to look at modifying the piston first rather than the exhaust port as pistons are cheap and plentiful in comparison. Has anyone gotten results from doing this??

3) I downloaded the 2 Stroke Wizard 5 ex pipe software and will be fabbing a new pipe. Initially it looks like the Malossi pipe is way different than what is recommended. Anyone have experience with this software and results?

4) I milled the head down .030" but as this is still a stock head, it is going to be really tough to get the squish down to .6-.8mm (.023"-.031") without milling another .030" and sending the compression ratio super high. I am thinking of either buying another head or welding and grinding the squish area of the stock head. Anyone have pics of the chamber side a Naraku or Polini head for stock bore size?

5) What spark plugs do you guys like for these things??

[swimmingfree]

have a question for you .... what is the compression now???
swimmingfree

[LMH]

.

[Red Eft Performance]

Killing time before the next event (World Finals) at Bonneville at the end of September and looking for more power. A couple of things have me scratching my head.

1) Engine does not want to turn over 9000rpm. My thoughts are the port configuration and pipe are the limiting factors here. which leads me to..

2) I have been doing quite a bit of reading (the A. Graham Bell book is pretty good though old) and it makes sense to look at modifying the piston first rather than the exhaust port as pistons are cheap and plentiful in comparison. Has anyone gotten results from doing this??

3) I downloaded the 2 Stroke Wizard 5 ex pipe software and will be fabbing a new pipe. Initially it looks like the Malossi pipe is way different than what is recommended. Anyone have experience with this software and results?

4) I milled the head down .030" but as this is still a stock head, it is going to be really tough to get the squish down to .6-.8mm (.023"-.031") without milling another .030" and sending the compression ratio super high. I am thinking of either buying another head or welding and grinding the squish area of the stock head. Anyone have pics of the chamber side a Naraku or Polini head for stock bore size?

5) What spark plugs do you guys like for these things??

1. That pipe isnt a good match for what you are trying to do. Pipe is holding the rpms back.

2. Yes you can modify the piston to adjust port timings. I have done this Many of times. What cylinder are you currently running?

3. Sorry I dont have much experiance with that program. But I will say even with the program and math building a 2 stroke pipe is all about trial and error. Test Test Test.
Even the top Performance companies have pipes that just never worked like they should have. Those same companies have pipes for other motors that are the Best!

The program is good though cause it will give you the best starting point! Once you get the Chamber close you can start playing with lengths to dial it in to the cylinder.
I would set up the cylinder first then use take those values and plug them into the program and build the pipe to match the cylinder.

4. I can get you a Malossi 50cc head if you want. It has a better squish area and optimized combustion chamber.

Shoot me a PM if you want some help!!!

Keith

[Revolutionary]

I spent Saturday building a pipe to the specs from 2 Stroke Wizard exhaust calculator. Knowing this will be a race only pipe, there is no muffler on it, and d*** is it loud! At the same time as this change, I also installed a set of V-force reeds.

As I mentioned previously, the Malossi pipe petered out at 9000rpm, with one jet change this pipe and reeds are ripping up to 11,000 rpm. .

I scoped out some country roads nearby and tomorrow I will take it for a long spin to see how it actually runs with and without the sidecar.

[Revolutionary]

After fiddling with the 24mm carb for awhile, I relented and dropped to a 21mm and it is much more responsive. Found a nearby country road and ran through a number of jets after getting the slow jet dialed in. It seems to like a 90 or 95 jet without any real difference in speed. Going to 85 jet saw a little piston speckle on the spark plug so I brought it back to 95 for safety. Cyl head temps are about 320-330 at the end of a wide open mile. Still using a -6 heat range plug but have a -8 that I will swap to.

I put in a yellow torque spring recently and had to keep dropping the roller weights to get up enough rpm to move this heavy rig. Now running a set of .197g rollers. I may find a heavier spring and lighter weights to bring the rpm more on the pipe before dropping down.

Regarding the pipe, the engine does not really have enough power to get to the power band and take advantage of the pipe as I made it. it will get up to about 8200 then drop down and when cruising at max speed is only at 7800. I will lengthen the primary pipe and the center straight tube to drop the rpm band of the pipe down and hopefully that will get me more in the power band.

For my testing yesterday, I stuck back on the stock cylinder with a fresh set of rings and hone job to see what the compression is and how it runs. I will swap back to the Naruku jug tonight then work on the pipe

Currently running 47.2mph on the gps with the following setup.
stock jug (50cc) with fresh hone and rings
very mild exhaust port cleanup
head milled .030"
8.4 gears
90/90-10 tires
yellow torque spring
.197g rollers
21mm OKO with 45/95 jets
malossi CDI
polini ruckus variator
Klotz 100 octane mixed 32:1 with R50

I have hit the nitrous a few times to see if it is noticeable, and it is slightly. Have not checked speed changes with it.

a long way to go to 62mph...

[Dan Diego]

Awesome project !! We are all rooting for you.

And please let us know if your Malossi pipe goes up on Ebay !

[ped]

Hi Rev. great build. Very nice work.
when I was running my Polini ruckus variator. On my S trans, My RPM went down. And My speeds went down. if you're not running the ZX trans I change that. I would get a Malossi variator 4 S trans. And 8-7grams rollers. I also added a 1000 rpm spring in the rear. it did give me a better top end speed. because you're carrying the extra weight you may have to keep 1500 rpm spring. I think it's going to hurt your top end on 49cc.
the weight and wind resistance is going to be a big factor when you start reaching 60 mph.
consider a small chloroplast wedge where you can hide behind it as you ride. something in a v-shaped. I say this because at high speeds when I go behind a car the scooter increases speed. A boost if you will. less resistance. very cool scooter.

[Revolutionary]

I added 1.8 inches to the primary section of the pipe and took another .010 off the head. Went to my same country road for testing today

First run put on malossi pipe and ran a steady 49 and peak 49.5

Second run put my pipe on and it ran a steady 53 with peak at 54

Third run swapped to a piston slightly modified dropping the crown by the ex port. Ran steady 50 with peak of 52.5 mph

This was all with the 21mm carb with 95 main jet and cht running about 330. Spark plug looked great. All three runs within an hour.

[paulpauly7]

pipe building is a art .Im in the process of modifying a FMF fatty pipe to fit my ported TS185 motor thats in a xr200r prolink frame .

[Dan Diego]

There is no substitute for reducing aerodynamic cross section... can you lower the handlebars 6 inches or even a foot?

[Revolutionary]

Don, you are right about reducing the aerodynamic footprint. If I make any more changes to the frame, it will require that I just make a new frame from scratch as I can barely get my body any smaller to fit and maintain control. Fortunately, my dad will be doing some of the riding and he is about 5'8" and 140 lbs.

Once I come back from Bville, I will assess where to go with the project. I am having thoughts of building a locking rear belt drive or similar direct drive system to reduce belt friction. V belts have tremendous waste friction - that is one big reason why all new cars use serpentine systems now. Another thought is to do some major wok on the head, ports and crankcase.

There is obviously a learning curve with these little things, but so far, running 54mph on 49.3cc is a good start. And I still plan to spray the nitrous after the first couple days....