Modern Vespa

Good Morning Everyone

perhaps someone here can assist me with an educated guess and advice please

I reciently bought a Bollag VM 137 upgrade plug and play kit from Mr. Bollag himself.
on Friday I attempted to install the kit but have hit a snag on the installation and wondering if anyone might have some advice on my issue.

the kit comes with a 2mm raiser base plate, Cylinder kit, Piston and Head the issue I am having is when I install the kit the piston is knocking the head,
the head has got a 2mm raised angled skirt which slips into the barrel to assist with squish and this skirt is what is being knocked.

Mr. Bollag has tried to assist with things like making sure my crank is correct (VN motor = 55mm stroke) and also making sure the raiser plate is installed both were but I am still having this issue.

I considered the following two things I know both will change the performance of the motor BUT I got this kit not to race the bike but rather to at least be able to keep up with modern day traffic.

1. Make some paper gasket and place on under and ontop of the 2mm base plate, will try different sizes starting with 0.4mm top and bottom to begin with and slowly add sheets as I go.

I know this will change not only the squish but also port timing slightly on each gasket installed BUT right now the squish is negative number anyway.

2. machine the skirt of the cylinder head slightly lower by a few point mm.
perhaps before I try either of these 2 items someone here can advise something else for me to attempt as Mr. Bollag says

"Hi Sir

I have no clue what the problem is. I've sold and mounted many kits without any problems.

My suggestion is to find the problem and solve it. Workarounds normally don't get a fully satisfying solution. But its your engine. Its up to you to decide how to mount the kit.

I can't give you my approval for this solution, because I don't want to be responsible when it doesn't work. The only thing I can do is wish you good luck." I totally understand that there is little he can assist me with from Switzerland and his response but still does not help me and my build

I wish I we in South Africa had all the mechanics for scooters like in Europe BUT sadly this is not the case with only a hand full to get bookings with them is difficult so i tend to try do as much of my own work as I can

PLEASE HELP

Video at thise URL of the knocking noise https://www.facebook.com/669052212/videos/pcb.4811406638935057/757664425207181

Video is really hard to watch and see anything. Can you make one higher resolution, turning flywheel slowly by hand, not using kick starter. Guessing the piston top is touching the head and pushing it up, from your description?

Have you physically measured stroke length? You may have something unexpected.

Why do you think that sound is the piston knocking the head?
I think you will find if there is any contact at all - you will not be able to turn the motor over completely. It will simply stop when you reach the point of contact.
Something else is going on there - though not sure what.
One way to confirm this: you can put a piece of solder on the piston - look up how to measure squish with solder.
I think you will find that it gets squished - but does not flatten completely.
Does the noise go away if you turn the flywheel with the head off?
You can bolt just the cylinder down - using spacers between the nuts and the top of the cylinder - without the head on it. I suspect you will still have the sound - but you may see at what point it is occurring.

One note: if you do this - be careful not to torque too hard on the head bolts - as the spacers will dig in or crack the cylinder if over tightened. If you have some small springs to use as spacers - this is a great way to do it.

so this video was taken with the head not torqued down fully but slowly to a point I started getting this knocking sound,

with no head there is no noise even when the head is on with the nuts just touching still no noise but as I start nipping the nuts then I get this knocking on the head I can even see where the head is being touched, I have tried then tightening more on the opposite side of this point of impact which eventually does totally stop the piston from moving.

I did measure the stroke length was the 1st thing I thought of but seems correct,

I made a plate that I tightened between 2 of the studs and measured BTC and TDC to get me 55mm which is apparently the correct stroke for the model

The only thing that makes sense is your assumed 54mm crankshaft is a 57. is it the original crankshaft that would have been fitted to a 125cc cylinder? Other than that, then it's an issue with the cylinder/packer/head. . . But that is a scientific wild ass guess.

Personally, I don't see the value running the Indian cylinders when you have the mighty Pinasco 160.

I got this kit from Ralph Bollag in Switzerland DIDNT know its was indian
there is absolutly a chance the cylinder is a 57mm but I did measure and measure again,

will do it one last time

Is this kit for 54mm stroke rather than 55? You mention 55 when you measured but both Gick and SIP are saying its for 54.

The cylinders are made in India and have been for decades for tuk-tuk. others use the same cylinders. not to say it's bad, but certainly dated.

https://www.sip-scootershop.com/en/product/racing-cylinder-sip-farobasso-151-cc_20119070

https://www.sip-scootershop.com/en/product/racing-cylinder-farobasso-151-cc_21190000

https://www.scooter-center.com/en/cylinder-bgm-pro-150cc-wideframe-faro-basso-oe-57mm-stroke-57mm-vespa-1953-1959-vm-vn-acma-from-engine-v55-vb1t-vgl1t-vl1t-bgm1550?number=BGM1550

I got this kit directly from Ralph Bollag and he gave me a kit for what he says is a 55mm stroke set up

So honestly dont know now

So this is for a 125cc not the 150cc think that is the difference on the 55mm and 57mm would i be correct.

https://www.sip-scootershop.com/en/product/racing-cylinder-bollag-motos-137-cc_20119059 this was the kit but i got it directly from Bollag

also teh cylinder has his logo, I assume thats easy enough to add with an etch tool right so I don't know if the cylinder is from India or not

I now wish I spent more time doing research on kits for the Faro Basso, but its done and I am sure it will be a good ride as I said i am not looking to race her but rather get to ride in modern traffic so the dated stuff I am sure will be okay for me

The crankshaft needs to be 54mm stroke. No one makes a off-the-shelf 55mm stroke crankshaft for the model; no sense either.

well you are in luck. the Pinasco is not a "race" cylinder. . .. but a modern cylinder for 55-57 wide body motors.

The Indian tuk-tuk cylinder can be bought out of India for around $25.00. small shops and manufactures can then machine the cylinders to their liking. Some add CNC machined heads.

Oh well too late now to get a Pinasco the number of fender lights here in South Africa will make trying to sell this Bollag kit almost impossible

let me check set up today and check the stroke again

Lets assume my initial measurements were as true as a politicians promises and it is infact a 57mm stroke do i then rase the base with a thicker base plate as a solution

57 it is then. Put the extra 2mm packer on the head. Will work out better without any grinding.

was at my mate last night made some base and head gaskets in various material and thicknesses

decided to make a head gasket with the bolt holes, dont like a ring gasket always worry about twisting a head when torqueing down

What did you find on the stroke? The problem with fiber gasket is they compress use metal.

Seems after measuring again and again I have a 57 stroke, I have spoken to Ralph about this and was told that for the 57mm stroke to work I would need to use a 1mm base gasket and different head BUT he no longer makes that style head,

so now either I need to sell this kit to someone with a 125cc (very few and far between here in South Africa) and buy a new 150cc kit from SIP or replace crank with a 125cc 54mm crank OR use base and head gaskets.

now i am going to have to work out the actual size base gasket and head gaskets I need to use to maintain the correct compression and squish and also how the new base gaskets will affect the port timing.

I have been able to install 2x 1.25mm gaskets top and bottom of the aluminium base gasket and a 1.5.. head gasket this has now changed the port timing BUT the squish is still at about 1.5mm slightly bigger than what was recommended by Bollag (1-1.2mm) but i also have not yet torqued the bolts down

use the 1mm base gasket as suggested, check port timings with that. Then adjust thickness of gaskets if needed to get ideal port timings. Then measure squish (will probably be too much), then have the cyl or head machined the appropriate amount to get the ideal squish. should be ok and no need to sell the kit you have. this is typical, as nothing ever really fits 'off the shelf'

As said already. Least damage to the port timing will be to put the extra 2mm on the head gasket.
Leaving the squish at 1.5/2.0mm will get around the compression going up with the 2mm extra stroke. No need to do anything just bolt it up and enjoy.

Do you know where exactly I can find such a cylinder from India? TIA

You can buy them through IndiaMart. You would have to be on drugs to use them; many people are!

Which drug (or drugs) would you recommend to go with an IndaMart head?

crack/meth.

I think I need to see for myself. as long as the piston doesn't swell, the rest can be corrected

Okay so I was not going to just use this barrel as a paper weight even though I was told its old tech I bought it and had it so used it

I have finally got the new head, and replaced the Crank, now to set up and ride.

Could someone assist with carb settings please

with the Kit from Bollag he sent a list saying preset up for the 151 kit which is running a 105 main jet set up for this build but I can only assume that is at Sea Level, due to the fact I am at around 1700m above sea level I assume it should be safe to down jet up to around 5 points but more or less 3% is what I would like to try.

The bike is running but bogs quick and lots of 4 stroking,