Longstroking Malossi 166, JL RZ port timings

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Jackomad5
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Posts: 16
Joined: Tue Jan 23, 2018 10:11 pm
Main scooter: LML kitted
Location: Stoke on Trent
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Sun Sep 09, 2018 4:37 pm

Hi guys, I’m in the process of adding a long stroke bell crank to my malossi 166 LML motor. As part of the install I need to get the port timings sorted.
The crank itself uses the longer 110 rod. So as I understand I need to first lift the barrel with a 5mm spacer then add an extra 1.5 for the stroke increase.

I was hoping to get some idea of what timings I should be aiming for to suit the exhaust (revolver/JL RZ mk1 copy) from online calculations it seems that adding the extra with a head spacer will still give me transfer timing of around 125 degrees, still too much? (I have heard that this exhaust suits timings which are not too high) also it seems I will end up with a negative deck height, the piston will be out of the barrel by about 0.5mm is this ok provided that a head spacer is used to keep squish area correct?

Any input much appreciated!

Jack221
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Joined: Mon Jul 29, 2013 8:18 am
Main scooter: PX221
Location: London
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Tue Sep 18, 2018 4:56 am

125 is not quite enough. Set the piston flush with the top of the barrel.
Vespa est ieiunas, quia semper operaturi

Jackomad5
registered user
Posts: 16
Joined: Tue Jan 23, 2018 10:11 pm
Main scooter: LML kitted
Location: Stoke on Trent
Contact:

Fri Sep 21, 2018 2:06 pm

Cheers Jack, I may just end up trying the effects of different timing

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