Author Topic: "barn find" (Read 16242 times)

Rgconner · « **Reply #75 on:** February 07, 2012, 10:48:21 AM »

He is going to wield bands around the clutch basket and put in better springs, better cork.

Rest will stay the same unless we change the fourth gear to cruise better in the hills.

oh, and a really cool carb with an adjustable main jet and air bleed!

grcamna2 · « **Reply #76 on:** February 07, 2012, 02:01:40 PM »

Rg,
When you say "adjustable" main jet...? how is it adjustable..for mixture?...on the fly

...possibly ??

Rgconner · « **Reply #77 on:** February 07, 2012, 02:14:42 PM »

Quote from: grcamna2 on February 07, 2012, 02:01:40 PM

Rg,
When you say "adjustable" main jet...? how is it adjustable..for mixture?...on the fly ...possibly ??

Well, you have to pull the side cover and get at the screws on the top of the carb, but you can adjust the mixture on the side of the road.

Very useful when you ride the Sierras and change altitude from 0 to 8K feet in elevations.

grcamna2 · « **Reply #78 on:** February 07, 2012, 05:02:40 PM »

I am really glad someone thought to design such a nice feature.I burned up my freshly rebuilt Yamaha RD350 out 75 miles E. of Blythe CA. back in 1986 traveling from CT. to CA. I had to hitchhike away from it and leave it there at a mini rest stop in the AZ. desert on I10. If I only knew what the elevation was during my travels

...The street maps you buy really ought to have a topographic feature to them

. I was going down in elevation when i thought I was going up and I was doing jetting along my journey...nobody in convenience stores knows the local elevation...that's for sure.I should have taken a mini altimeter like I bought from Pep Boys recently.

Rg, do you have signs along your routes that give you the elevation ?? or do you just go by how it feels and plug color ? Have you ever did jetting runs on a long ride ?

Rgconner · « **Reply #79 on:** February 07, 2012, 05:44:13 PM »

Every city has the elevation, and every pass has the elevation.

I run the Honda set for the valley. Sometimes I lean out the idle circuit and let it run rich on the open road.

grcamna2 · « **Reply #80 on:** February 07, 2012, 05:57:04 PM »

Where are you located ?

Rgconner · « **Reply #81 on:** February 07, 2012, 07:20:09 PM »

Sacramento. The foothills are just a few minutes away. Great twisties on any number of roads out here.

grcamna2 · « **Reply #82 on:** February 08, 2012, 08:30:33 AM »

Quote from: Rgconner on February 07, 2012, 07:20:09 PM

Sacramento. The foothills are just a few minutes away. Great twisties on any number of roads out here.

Now I see why you want to give your P200 a lot more power

...I've driven through Sacramento before..and that traffic will really "run you down" if you don't get out of there way

. It must be nice riding outside of the city and..in the foothills.

Rgconner · « **Reply #83 on:** March 01, 2012, 07:38:05 AM »

So, an update. The engine is in the shop, I am next in line.

In the interim, we were talking about how we could do something for the 250gts Vespa. Stock is 19 HP.

On of the problems is that no matter what you do, put a pipe on or put on the 4 valve head and kit from Malossi, you can't get more than 21 HP out of the engine.

The mapping prevents that and will not deliver the fuel. Even if it did, the max fuel it can deliver is going to limit you to about 23hp. Some people have tricked the ECU by modifying the O2 sensor output. Results are mixed, as it is a dodgy fix.

Enter the Intelajet. This is a self tuning fuel jet that augments the fuel stream by "listening" to the detonation and adding fuel as needed.
I suspect he does this with a tuned chamber of some sort that is tuned to the distinct rich/lean noises and engine makes. Vacuum demand makes a difference as well.

It can deliver 15 to 20% more fuel to the engine above what the injector does, in a very fine mist of fuel. The ECU is know to be able to only adjust up or down 5%, so we can override it. You can add more than one jet too, if we really needed that much fuel.

It has a remote dial option($199 total) so you can in fact re-jet the carb from the handlebars. The older and cheaper product ($99)requires accessing the carb area where the jet is mounted on the boot. For the Vespa, that means lifting the seat removing the underseat storage, about 15 seconds.

Our plan is to mount it in a velocity stack spacer he makes for stock carbs but he has made for the GTS throttle body. We also need a still fuel supply, so he is going to cut up an old Deltoro carb (he has dozens of ruined ones lying around) so we have a floatbowl. Tht is only needed for a fuel injected system, carbed bikes you draw from the drainscrew from a modded drainscrew witha nipple on it. Add a cold air intake and an aftermarket exhaust will put the bike in a lean state where the Intelajet can add fuel.

There is nothing else like it on the market for fuel injected Vespa engines. We're hoping to sell the kit for $800 or so, depending on the choice or the remote tuner or the old fashioned one and the pipe we provide. He wants to start bending pipes, so there might be even more margin there if we don't have to outsource that bit.

Without the 4 valve upgrade the estimate is 20% more HP, a real gain. With the 4v it is hard to say, it might mean 30% or more.

This would work for the Vespa 125 too, making a very light bike (275 lbs I think) generate up to 20hp if the numbers hold. Very nimble bike too, with a short wheelbase.

grcamna2 · « **Reply #84 on:** March 01, 2012, 05:49:25 PM »

Rg,
Do you own a 250gts ?

Rgconner · « **Reply #85 on:** March 02, 2012, 07:17:35 AM »

Yes, that is my "primary" bike.

It is a nice setup, automatic and lots of storage space on it.

They are very snappy off the line, but above 40 acceleration is a little laggy.

grcamna2 · « **Reply #86 on:** March 02, 2012, 10:19:45 AM »

Will you completely modify the 250gts for maximum power output such as you have been describing ?

Rgconner · « **Reply #87 on:** March 02, 2012, 10:38:04 AM »

I don't know. I am going to do everything but the 4v head/block as it is a major job + $1000.

grcamna2 · « **Reply #88 on:** March 02, 2012, 12:26:32 PM »

The work you described...does that also include getting a different flywheel? and will all the modifications you described in a previous post take away ALL the "snap off the line" the 250gts has ?

Rgconner · « **Reply #89 on:** March 04, 2012, 08:47:19 AM »

The P200 is not getting a new flywheel per se, but it the existing one is getting shaved by about 1KG, the stock is 3.5KG or so. 8lbs? Bringing it down to the 6lb range.

This is required on the 2 stroke because Vespa put an over sized flywheel on it to compensate for poor torque on the low end and to make it more "reliable". By reliable, they mean you can be lax about servicing and it will still run.

Then, to smooth out the thrash from such a large flywheel, they use a spring driven cush drive on the primary gear. We have the same thing but on the rear hub, those little rubber wedges help dampen some of the chain slap. A common failure on the older Vespa's are the springs in that cush drive, the bike will buck and if you ignore it, you can bend the crank.

The lighter flywheel will allow it to rev up and down faster. It also allows the engine to reach higher revs. Stock is something like 6500 to 7000, where this will reach the 9000 range I think.

The 250GTS is more like the SOHC/4s, it does not really have a flywheel. Unless you count the variator, which is part of the Continuously Variable Transmission (CVT).

(If you are unfamiliar, the RPM of the engine stays the same and the CVT transmission changes gearing to provide acceleration. So you hit max power/torque immediately and stay in that RPM until you back off the throttle or hit the limit of the CVT. On an unmodded bike, that is 6000 RPM, with freeway speeds at about 8000RPM to the limiter. )

Those can be replaced/tuned as well. Usually so that on take off from a stop the engine reaches the max power band quickly.

grcamna2 · « **Reply #90 on:** March 04, 2012, 09:03:00 AM »

I appreciate the help in understanding the system on you're 250gts drive.That's a 2 valve 4 stroke...correct ??

Rgconner · « **Reply #91 on:** April 10, 2012, 10:55:33 PM »

Update:

The P200 is up and running, and it is a torque monster. Get too aggressive and that front end comes right up in 1st or 2nd.

Some pictures of the work done, showing the crank, the lightened flywheel, head and ported piston:

Close up of the absolutely sexy crank work:

Work to the case was done as well, porting out the rotary valve pad and the exhaust port to match the cylinder. Compression ratio came out to 10.8:1. Requires midrange to keep from knocking, loves the premium.

The engine is still really tight and won't go over about 55 in 4th gear, but that is ok. Run in on a new engine is about 500 miles, but this one is really, really tight. The rotary valve clearance is well below the 3 mil spec and the crank arm small end bearing needs time to work itself in.

grcamna2 · « **Reply #92 on:** April 11, 2012, 07:35:54 AM »

Nice Race mods Rg

,
I love the crank..and especially the piston w/ "Doorway" transfer ports rather than little transfer "windows".I read that you have the port tracts in the crankcase and the rotary valve to match

? Do you plan on doing endurance racing ?

!
It must be excellent to have a friend who helped you figure out you're build needs and then custom match all the mods to you're specs. Great Job !

Rgconner · « **Reply #93 on:** April 11, 2012, 12:12:38 PM »

I would love to do the Scooter Cannonball one of these years!

http://www.scootercannonball.com/

The guy who did the work is Al Harpham out of Fresno, http://hotrodscooters.com.

His website is horribly out of date. He has been doing these builds since the 80's and has several stock tune sets, torque, high RPM, and can do something in between if you want.

He is going to get into SOHC/4 as the number of 2-strokes is on the decline. He is busy as he can be, but that won't last forever.

I pointed him at the Gentleman's Express article that shows how to conservatively get more horsepower out of the CB550. We may do a project next year to build up a spare engine from scratch and swap it in. He is going to hit up some of his machinist contacts to get details on how to port the CB550 head.

He has low overhead and does not charge excessively for his work. Parts and labor came to about $1400, but we completely stripped the cases and replaced every bearing and seal with the best we could get and a new carb, plus a vented drum brake for the front. (Still on its way, delay on getting the bearings)

If I would have bought the aftermarket versions of what he did I would have spent the same after getting the cases ported.

And still would have not seen the gains or have the reliability of machining stock parts.

grcamna2 · « **Reply #94 on:** April 11, 2012, 06:25:50 PM »

I like that Cannonball Run idea..looks Fun

.I imagine you're Engine in it's present state of tune must feel like it has at least Double the power & if you were to put a flow meter on you're intake port you'd most likely see a Huge Draw ! Does it still have decent Low to Midrange Power?...or more all the way across ? Do you get a few more(tach installed?) Rpm's now ? how do you like it for long rides & on the Interstate ? I'd love to ride it..it's gotta be a Blast

! I hope you can break it in for top Rpm performance when you're done w/ the low rpm break in.

I also love the idea of modified O.E. Vespa parts rather than Custom; they still have lot's of life left in them and many of the critical surfaces are already worn in smooth !
Were the crankshaft flywheel/weights knife edged modded and cut to allow more smooth flow & ram charging of the crankcase ?

You were Blessed w/ an Excellent deal on parts..AND Labor...Man

!

Rgconner · « **Reply #95 on:** April 11, 2012, 07:33:25 PM »

I would have to ask Al

The carb draws a tremendous amount of air. I am running a 179 jet... stock was 108!

So that is 50% the diameter larger, and twice the potential gas flow. It is running a little rich, but Al says wait a few weeks, it might lean out as the engine settles in.

With OEM parts, and some "aftermarket OEM" (made by same factory, different label) parts, I can go up 8 oversizes

There is huge pulling power at all ranges of the band, but it is not revving out past 6K yet. Too tight. This is based on MPH vrs gearing known limits.

I went with a conservative pipe that looks OEM but has better flow. Not as aggressive as some of the stuff out there but does a good job.

The run yesterday the bike would not accelerate well in 4th. Today I was able to get to 55mph with decent acceleration.

grcamna2 · « **Reply #96 on:** April 11, 2012, 07:58:42 PM »

Good..you're letting it break-in by how freely the engine Wants to rev.I know you'll be happy once she's got 1K nice smooth progressive stage rpm miles on her.
Will you install an electronic tach ?
I like you're choice of exhaust as it will give you decent low-mid power...you must already realize the potential top rpm pulling power you'll have once she's fully run in

. I like this thread For Sure ! Love those little engines with small cc's but good power potential.

Rgconner · « **Reply #97 on:** April 11, 2012, 09:48:23 PM »

I am looking at a combo Tach/Speedo/Head temp/ EGR unit from SIP Germany. Almost $200 tho, so not yet.

Absolutely necessary on long runs or you risk seizing the engine if it suddenly runs lean or the auto oiler stops functioning properly.

grcamna2 · « **Reply #98 on:** April 11, 2012, 10:06:41 PM »

+1 on that

grcamna2 · « **Reply #99 on:** April 13, 2012, 07:25:55 PM »

Rg,
I noticed a P200E red w/ a black sidecar in town today..;the P200E is a very light weight little scooter.I imagine yours will be a "sleeper" w/ all the power you've given it ! They must have good power to weight ratio even stock.

News:

Author Topic: "barn find" (Read 16242 times)