30 mm Delorto

[lammy150]

I have a Malossi 210 with

SIP head
new piston and rings
mazacheli race crank
casings matched and ported
T5 4th
SIP EVO JL exhaust.

Currently has a Delorto 30mm PHBH breathing through frame via malossi bellow. It is mental in 1st 2nd and 3rd. GPS'd at 57mph in 3rd. When you change into 4th its like the fuel tap closes, starts to slow down, revs die off and top speed peaks at 65mph.

Is this a jetting issue? What carb setup would you recomend?

Should I consider even changing the carb?

[mick1]

Sounds more like a "power issue". I think your carb' is ok but you may have your port timings wrong (for the exhaust) and may be missing the power band when you get into 4th. Another option might be your compression is too low ? Have you checked ring gap, head volume, etc ?

A dyno run might point you in the right direction....saves a lot of guess work

[lammy150]

Well that makes sense. The head, piston, and rings are brand new. Probably the first port of call is the port timings. There is no scooter friendly, 2T friendly rolling road here in Northern Ireland. Only three exist which are motorcycle friendly! What should we be looking for when it comes to the port timings?

[Norrie Bodge]

Is the crank you using 57mm or 60mm ?

[lammy150]

embarrassingly I have no idea. I am in no way mechanically minded and got someone else to do all the work

[lammy150]

a friend reckons its not 60, so must be 57.

[LI150]

This is the age old problem of the 210 dies in 4th. I got round this by changing the gearing to 22/68. I highly recommend this makes the 210 great fun.

[nuttyboy]

Sounds like gearing to me as mine does same it's 185 with 30mm delli Spanish 150 special box.

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[Norrie Bodge]

Sounds like gearing to me as mine does same it's 185 with 30mm delli Spanish 150 special box.

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we talking Vespa here m8... dont thinks an LI-150 gearbox will fit

[Norrie Bodge]

a friend reckons its not 60, so must be 57.

does it have a packing plate/gasket underneath the cylinder? & also a head gasket?

if-so what thickness are these m8??

if defo 57mm you will probably struggle at top end,

before spending ya money on a 60mm crank, you can try altering the piston as likes this, & should pull loads better


http://www.worb5.com/vespa_lambretta_sc ... mahle.html