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MV Santa
GTS250, 1975 VBC, 1980 P200E cutdown
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MV Santa
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He's looking sharp after the resoration but still has the same clunky old rotary valve motor that starts only when it wants to. Even when it does run it tops out at about 40mph which rules out out of town group rides. I'd sure like to have a modern LML motor but was wondering what I was up against. Would I have to add a battery? Kick start is OK. Oil injection is nice but I would rather not have to cut a hole in the body for the sight glass. Also I would like to keep the 8 inch wheels foe aesthetic reasons. If I get a motor geared for 10 inch wheels is it necessary or even possible to regear it? Will the brakes fit? Is there a thread that I can read where someone has don this? I have a lot more questions but that's enough for now. Thanks.
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⚠️ Last edited by vintage red matthew on UTC; edited 1 time
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VNB VSC VMA VSX - o9c vbc vmb
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Lots of work, and it has been done for sure... but after you count up all the sheckles and time it would cost to do the conversion, you'd probably be ahead if you just shopped around for a well sorted Sprint or similar.

Your VBA is pretty, and its a VBA so... yeah, rides like a VBA, etc. I'd enjoy it for what it is.

That said.... this might be some help to ya, (or not) -

http://web.me.com/camintosh/1962_Vespa_150_LML_engine_replacement/1962_Vespa_150_LML_engine_replacement.html
⚠️ Last edited by Birdsnest on UTC; edited 1 time
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Primasarah
1979 P200E, 1977 Rally 200, 1974 Primavera
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Primasarah
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Buy a sprint. At the end of the day you are going to spend a ton of coin to put a 8inch conversion and lml motor in that frame.
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UTC quote
and more general info here via search...

Lml engine in a VBC
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2006 GTS 250
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Matt I really hope you can sort out all the troubles with it. It really is a beautiful scooter. I think now that you are storring it at your Mom's garage away from Angeo things are going to start looking up. Maybe he is just jealous of Angeo and can't stand being side by side with him. Scooters can be very temperamental when it cames to attention.
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Re: Guiseppe wants an LML
vintage red matthew wrote:
He's looking sharp after the resoration but still has the same clunky old rotary valve motor that starts only when it wants to. Even when it does run it tops out at about 40mph which rules out out of town group rides. I'd sure like to have a modern LML motor but was wondering what I was up against. Would I have to add a battery? Kick start is OK. Oil injection is nice but I would rather not have to cut a hole in the body for the sight glass. Also I would like to keep the 8 inch wheels foe aesthetic reasons. If I get a motor geared for 10 inch wheels is it necessary or even possible to regear it? Will the brakes fit? Is there a thread that I can read where someone has don this? I have a lot more questions but that's enough for now. Thanks.
With the LML, you would have to change out the gearing which is kinda a pain in the ass. otherwise you limit yourself to the 40mph you are currently hitting.

i recommend just getting your original engine running correctly. Rotary valve engines when set up correctly, are 1st kick scooters. I have 8 inch scoots that are dead reliable and reach highway speeds of 50-60 with power still to be had.

Best,

Jg
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Ossessionato
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I've done the LML 8" conversion but only because the original engine was beyond hope. Didn't change the gearing but usually start off in 2nd gear because it's geared so low. And yeah, it does about 45 mph but that's what it was designed to do. If you've got a functioning scoot, ride it as it was intended. Want to go faster? Change the scoot.
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MV Santa
GTS250, 1975 VBC, 1980 P200E cutdown
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MV Santa
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Points well taken. Maybe I should try to address the root problem. It just doesn't have enough spark. I've changed the points, condenser and coil. I've adjusted the timing and point gap every way that I know how. I've had the flywheel remaged twice. Still it will not spark unless you close the plug gap to 10 thousandths. The plugs foul at the slightest provocation. Do you think a new stator would help? I've heard that they are either good or bad. They don't get weak. What about electronic ignition? I would do it in a minute if I was sure it would fix it but I wouldn't want to spend the money and then still be in the same boat.
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Also, there is no matching the look of the older smooth castings.
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oopsclunkthud wrote:
Also, there is no matching the look of the older smooth castings.
LML castings are rough.
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ok, I'll be more clear.

I really really hate seeing old bikes with new engines. The worst is a GS/SS with a p200 lump in it. But a VBA/VBB... with an LML makes me almost as bummed. I know there are times when the original cases are damaged or lost but more often than not the old, infinitely rebuildable, engine is sent to the land fill and replaced with an LML. Then all the bodging starts to try and make the electrical work...

It is your bike and you may do as you like, but I have huge respect for a bike/builder/rider when it's got the original cases.
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MV Santa
GTS250, 1975 VBC, 1980 P200E cutdown
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Fair enough oops but then can you help me make it start? Because it's pretty useless as it is.
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ok, so what's the status of the engine, Totally stock?

stock crank?
rotary pad not cut?
Stock 150 cylinder with deflector piston and head?

Ignition, is that internal or external coil?
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MV Santa
GTS250, 1975 VBC, 1980 P200E cutdown
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UTC quote
Bone stock, deflector piston, external coil. I don't know what rotary pad cut means. I'm pretty sure that the majority of the problrm is that I'm not getting enough spark. I've changed everything in the ignition except the stator. Do you think that might help?
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UTC quote
The individual coils in the stator can be changed. Some guys even rewind them.
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MV Santa
GTS250, 1975 VBC, 1980 P200E cutdown
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UTC quote
Do you think that might help? Do they get weak?
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I don't think the internal coils go bad as often as they are replaced, and even when they are going bad you can sometimes fix them with heavy spray of electrical lacquer.

With the external coil I like to use the blue P125X coils over the stock bakelite. Also some of the new points suck, and some are fine, they should not wobble on the post at all.

my list of things to check in this case would be.

0. check that timing is spot on
1. Check/remagnetize the flywheel
2. check that the points and condenser are good, even if new

oh, also, Stock carb? new float and needle? All jets clean?
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MV Santa
GTS250, 1975 VBC, 1980 P200E cutdown
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UTC quote
I can assure you that I know how to adjust the timing. The recommend advance is the best. Two degrees off will not work.

I have remaged my flywheel twice with little benifdit. Should I do it again?
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MV Santa
GTS250, 1975 VBC, 1980 P200E cutdown
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UTC quote
I will replace the points and condenser again. It is very npossible that the new ones could be bad.
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Molto Verboso
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UTC quote
The wire(s) from the ignition stator coil, points, condenser, and then to the external coil and kill switch have fairly high spikes that can shock you. The insulation on that wiring must be good to prevent leakage to ground. The higher voltage really wants to find ground. Any leakage to ground subtracts from the spark voltage. The wire from the stator to the external coil, and the kill wire have been my major problems.

Remove the kill wire at the engine and look at the spark. Have you ever removed the stator and checked the wires behind to where they exit the engine? Look for brittleness and cracks. Carefully check the wires to the points and condenser, they can often get damaged doing maintenance. Pay attention to sharp bends. Look for scratches or whatever on the stator windings.

Have you tried a new plug wire and cap? Don't use a resistor cap or spark plug. I have resorted to watching stuff run in the dark and looking for sparks where they shouldn't be. You can look in the window on the flywheel and the only sparks should be at the points, and they should be minor. I sometimes use one of these for easier troubleshooting. O'Reillys and Advance auto used to have them.

http://www.toolfetch.com/Category/Automotive/Spark_Testers/THE404.htm

Have you positively found and marked top dead center, before adjusting points or moving the stator? And marked a spot for timing advance?

Grasping at straws, maybe try another flywheel. A magnet has to pass the stator ignition coil and produce voltage at just the right time in conjunction with points operation. I've never found one to be off position yet. Nor a bad stator coil. Like oops, I have been disappointed with new points quality.

Lovely scoot. Good luck.
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