Scooterotica

B-Race Tuning wrote:I've read this whole post three times now, and like many am perplexed. Bear with me on this please.
First comment I'd like to make is that 3x wheeler 175 cylinders DO come in small block stud spacing. BUT, you would not choose to use one on any "series" scoot as the inlet is "facing" the wrong side and although you'd be able to fit an inlet manifold, at the gasket face the direction would change by nearly 90*. (Fli175 anyone?)
If you're attempting to achieve the "experience" of a TV175 / engine then you won't achieve it by either reboring ANY 150 cylinder to 175 and lobbing a piston at it, or using any 107 rodded crank. Sorry, but won't happen due to port/time area, end of.
You have a newly produced or NOS TV175 piston? Size? Is it for a 116 rod or 107? Number of rings? thickness of rings?
If you have a NOS, standard size TV175 piston then in a perfect world it needs matching to a NOS unworn TV175 cylinder. VERY tall order that.
Your budget is now determined by the piston you've bought and a cylinder bought from India (I think that would have given you a good clue, but you go on to consider an Indian 116 Rod FROM india)
You also quote brand new Vespa cranks for £25.And presume you would consider using one.
So far, I read this that;-
you want to achieve this TV175 engine based on an SX150 engine. Feasible.
You want to achieve this with a piston and an SX cylinder. Feasible, but (regardless of crank) Outside budget due to rebore cost and extensive porting required to achieve TV port size through it's length.
If your piston IS TV and standard size it make sense to use 116 Rodded crank. Feasible, on an SX crank, but to get an engine worth doing, do it right first time and get the likes of Harry Barlow/ Readspeed et al to do it with a decent rod/ bearing so it lasts.
If you're going to do it right (after all it's to an SX casing so originality isn't the goal here), you'll use an electronic set up. IF you are then use GP webs. The SX/Li taper electronic flywheel bosses are turned down, points bosses. the machining off of the cam for the points weakens the key area (where it used to be thicker due to the cam). I've had more than a dozen customers with this issue. 50lb/ft can cause them them to split down the keyway.(log splitting wedge?)
So, Indian gp webs with a 116 Italian rod fitted by the likes of the afore, outright ?? £100-140?
And Joespeed has offered a 175 cylinder (ports should be correct if not a bored out 150, or the works been done, plus it's had a rebore and piston to match/ suit. FOR £100 FFS!
If your piston is std/TV?, SELL IT.
Buy Joespeeds, wait until it arrives (or clarify before purchase whether 107 or 116 rod (or 110/115), and get crank made up to suit.
If it's 107, don't expect a TV ride.
If Joespeeds (or any other that "eventually" comes along. We're ALL waiting, sometimes YEARS for the right part AT the right price), is too expensive at present then you won't achieve the build anyway. Harsh, yep. (and FORGET the piston you have unless you can sit on it and the build for a LOOONG time or sell it)(no I don't want it!)
I have a genuine TV175S3 crank sat on a shelf, that I would gladly give you, but it needs a new rod/ bearing- and postage, so no good for you.(and SX/TV taper!)
If I could locate half of my secondhand parts theres probably at least one TV cylinder, but would require a rebore, so no good for you.
I've just written your answer to this build, New Cranks aren't £25. Starting with a rare piston? (you haven't said size??) as a basis for this is not where to start.
Talking to Harry Barlow/ Readspeed (Jerome has a great stock of pistons and first class rebores [he even rebuilds cranks too]) et all will give you your ball park figure to achieve an TV175 spec engine,


but based on what you've said, we know it's too much.
Sorry, but face it, increase your budget, wait a long long time (stuff does come up for next to nothing) or give it up.
OH, and don't use £25 "new cranks", please.
Simon.

fluff34567 wrote:A new tv175 crank in UK is £135 or €118 in Germany. That's the cheapest I found as I bought 1 recently.

blimeyolriley wrote:

fluff34567 wrote:A new tv175 crank in UK is £135 or €118 in Germany. That's the cheapest I found as I bought 1 recently.

I what I cannot understand is why a vespa crank from the same manufacturers is only a 1/4 the price of a Lambretta crank ? you can buy a 4x cylinder Ford Focus crankshaft for under £100

blimeyolriley wrote:

fluff34567 wrote:A new tv175 crank in UK is £135 or €118 in Germany. That's the cheapest I found as I bought 1 recently.

I what I cannot understand is why a vespa crank from the same manufacturers is only a 1/4 the price of a Lambretta crank ? you can buy a 4x cylinder Ford Focus crankshaft for under £100

firekdp wrote:

B-Race Tuning wrote:The SX/Li taper electronic flywheel bosses are turned down, points bosses. the machining off of the cam for the points weakens the key area (where it used to be thicker due to the cam). I've had more than a dozen customers with this issue. 50lb/ft can cause them them to split down the keyway.(log splitting wedge?)
Simon.

Is that the case for all SX/LI tapered electronic flywheels? Points bosses have the keyway in a different position to electronics meaning that there isn't enough adjustment on the stator slots to time them correctly. I haven't had this problem on the ones I've done.
Also the cam on a points flywheel is on the opposite side of the boss to the keyway, so the keyway is already the thinnest part and wouldn't need any material removed from this area.