Search found 212 matches

by Jack221
Thu Jan 17, 2019 6:44 am
Forum: Vespa Tech
Topic: Malossi mhr cylinder tune...
Replies: 13
Views: 1988

Re: Malossi mhr cylinder tune...

The MHR60 comes out tame, as it is similar to the MHR57 with the 1.5mm difference fixed at the head. The only way to make the MHR60 go like the 57 on a 60 is to fettle it. As you have found out once fettled the story can change entirely. What durations did you end up with?
by Jack221
Mon Dec 03, 2018 5:43 pm
Forum: Vespa Tech
Topic: Quick action throttle
Replies: 1
Views: 587

Re: Quick action throttle

by Jack221
Fri Oct 05, 2018 11:52 am
Forum: Vespa Tech
Topic: polini 187 port timings
Replies: 7
Views: 1094

Re: polini 187 port timings

Can see where you are coming from. Tuning Lambrettas is quite a minefield and not surprised to see you have been left traumatised. Vespas are more predictable but still have their issues. Even the most tuning on an LC Vespa with 4 gears is really not that advanced when compared with racing motorcycl...
by Jack221
Tue Oct 02, 2018 1:43 pm
Forum: Vespa Tech
Topic: polini 187 port timings
Replies: 7
Views: 1094

Re: polini 187 port timings

Good effort but your porting is a long way from exciting. 172/119 are good solid numbers that give broad low power. I'm sure she goes fine. To go faster you'll need more than just a decent exhaust ;) If you want to beat those Chinese twist and go nutters, you're going to need way more duration. Save...
by Jack221
Wed Sep 19, 2018 5:29 am
Forum: Vespa Tech
Topic: Malossi mhr cylinder tune...
Replies: 13
Views: 1988

Re: Malossi mhr cylinder tune...

Opening the piston windows Is a given. Same as taking off the sharp edges and dressing the ports. Forgot to mention that. The Vertex piston seems way easier to do than the Asso. Much nicer. 225Worb, The 60mm MHR cylinder is a bit tame. The 57mm cylinder is more aggressive. Might be cheaper than Harr...
by Jack221
Tue Sep 18, 2018 4:56 am
Forum: Vespa Tech
Topic: Longstroking Malossi 166, JL RZ port timings
Replies: 2
Views: 481

Re: Longstroking Malossi 166, JL RZ port timings

125 is not quite enough. Set the piston flush with the top of the barrel.
by Jack221
Tue Sep 18, 2018 4:46 am
Forum: Vespa Tech
Topic: Malossi mhr cylinder tune...
Replies: 13
Views: 1988

Re: Malossi mhr cylinder tune...

The MHR 57 on your 60 crank will go like a heavily fettled old 210, straight out the box. Just bolt it on and set it up. I fitted this set up on my 221 after the old 210 wore out, a few months ago and now it rides like a motorbike. Goes over 8000rpm on a 35 tooth 4th. No gear gaps, pulls like a train.
by Jack221
Thu Aug 31, 2017 4:51 pm
Forum: Vespa Tech
Topic: Polini 210 squish
Replies: 8
Views: 1702

Re: Polini 210 squish

Malossi 221 with 0.9mm squish and Kytronic To give you something to think about. I do think there is no 'one size fits all' when it comes to squish. From what I have picked up over the decades, I have formed an opinion, that squish is all about the rpm that peak power is made at. The higher the rpm ...
by Jack221
Mon May 22, 2017 5:14 pm
Forum: Vespa Tech
Topic: Jumping out of 2nd
Replies: 3
Views: 923

Re: Jumping out of 2nd

Sometimes it is just a worn gear selector box and fixing that will stop it jumping for a good while. There is a refurb kit if the ally body is still tight enough.
by Jack221
Mon Mar 27, 2017 12:22 pm
Forum: Vespa Tech
Topic: Jetting phbh 28mm
Replies: 5
Views: 856

Re: Jetting phbh 28mm

If the bn270 is the atomiser, then I have never seen one of those, probably for a 4 stroke. In a PHBH on a 2 stroke, most use an AV atomiser for normal kits but an AS atomiser if you have something that revs a higher than the usual. 270 is way too big for a 225 MHR. I would start the jetting with an...