Going back to rotary
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Ossessionato
62 VBB1T Round Tail W/ leaner sidecar
Joined: 26 Jan 2019
Posts: 2241
Location: california
Mon May 03, 2021 9:51 pm quote
Watching with interest.
Went back and looked at mine.
Think I measured it right and ended up about 120/65.
- or close to it anyway.
(took me some time to stop confusing angles with timings).

I'm surprised your is at 77.
I would have thought it was closer to ~67 than 77 based on the photos.
Makes me wonder if I have my own measures correct.

Guess I'll find out soon.
Lead on!


This picture is from 18 months ago when I split my cases.

Jet Eye Master
PX221 MHR, O tuned PX200, PX125 and some motorbikes
Joined: 14 Jun 2017
Posts: 2755
Location: London UK
Mon May 03, 2021 11:45 pm quote
SaFiS wrote:
Yes, 108/77 is as is. Maybe the crank's a bit sportier than we wanted it??

This is the crank...
https://www.sip-scootershop.com/en/product/long-stroke-crankshaft-polini_45121000

Stock cylinder?? What is this??

Following this setup, will it work later, let's say with a big box exhaust (Pipe Design, LTH, etc.) or not?? If not, maybe a compromise then??
The sport kit on a 60 crank is sporty enough for it. 77 on a 57 might be too much.

Because the exhaust will be at 185 it could still run a box but why would you want to. The cobra will have a nice surge as it hits the power band, a box pipe will just be dull.
Ossessionato
62 VBB1T Round Tail W/ leaner sidecar
Joined: 26 Jan 2019
Posts: 2241
Location: california
Tue May 04, 2021 6:06 am quote
Quote:
The cobra will have a nice surge as it hits the power band, a box pipe will just be dull.
Public Service Announcement: Beware of addictive nature of this product.
Ossessionato
1979 P150X, 1983 P200E, 1988 T5, 1995 PX200E, 2011 Yamaha Fazer 600 S2
Joined: 02 Aug 2015
Posts: 2261
Location: Veria, Greece
Wed May 05, 2021 12:00 pm quote
Took some measurements today and this is what I came up with. Do they look correct?? Now I see why you said no stock cylinder after that. Pad opens quite a lot at the back (13mm)...



Ossessionato
62 VBB1T Round Tail W/ leaner sidecar
Joined: 26 Jan 2019
Posts: 2241
Location: california
Wed May 05, 2021 12:50 pm quote
Safis - I wouldn't have thought that was 77 - though it may be highlighting my lack of understanding rather than your's.
65 would be at the very edge of your pad.
I would have thought that Malossi would have cast the case to allow for as little as 60? ?

When I was trying to figure out how the hell to do the measuring - I kept confusing timings with angles. See Sime's explanation here: Vintage vespa with sidecar (Page 20)
This was easy - because the numbers weren't night and day different.

I'm curious - how are you measuring 77?
Ossessionato
1979 P150X, 1983 P200E, 1988 T5, 1995 PX200E, 2011 Yamaha Fazer 600 S2
Joined: 02 Aug 2015
Posts: 2261
Location: Veria, Greece
Wed May 05, 2021 1:09 pm quote
Pad opening is 55 degrees total. The 77 degrees come from the position of the piston when the crank closes the pad. It's 25.70mm after TDC. I have also measured it with the degree disc and it's the same. Crank looks like it's sportier than I expected...
Ossessionato
62 VBB1T Round Tail W/ leaner sidecar
Joined: 26 Jan 2019
Posts: 2241
Location: california
Wed May 05, 2021 1:12 pm quote
Ahh! Got it. (See - I confused it again.)
77 is the timing - not the angle.
Meaning - it is the combination of the crank position and the inlet opening.
Tks.
Jet Eye Master
PX221 MHR, O tuned PX200, PX125 and some motorbikes
Joined: 14 Jun 2017
Posts: 2755
Location: London UK
Wed May 05, 2021 2:19 pm quote
Calculations all look good. Going to run solid. Will be a fast touring kind of set up.
13mm out the casing means no going back. This will give you an 8 degree overlap. Transfers still 8 degrees from closing when the inlet starts to open. Keep the inlet shape just move 13mm. No need to work on the front.
There is more that can be done if it's not quick enough but I think it will be.
Ossessionato
1979 P150X, 1983 P200E, 1988 T5, 1995 PX200E, 2011 Yamaha Fazer 600 S2
Joined: 02 Aug 2015
Posts: 2261
Location: Veria, Greece
Wed May 05, 2021 3:15 pm quote
Jack, what if I was to cut a bit of the crank at the big end, so as not to open up the pad so much?? Won't be the same?? Say, 5mm off the crank and pad goes to 8mm instead of 13mm??
Jet Eye Master
PX221 MHR, O tuned PX200, PX125 and some motorbikes
Joined: 14 Jun 2017
Posts: 2755
Location: London UK
Thu May 06, 2021 2:37 pm quote
I always cut the crank in preference to the inlet. Easy to change crank. Makes little difference.
Ossessionato
1979 P150X, 1983 P200E, 1988 T5, 1995 PX200E, 2011 Yamaha Fazer 600 S2
Joined: 02 Aug 2015
Posts: 2261
Location: Veria, Greece
Thu May 06, 2021 2:49 pm quote
So, 5mm + 8mm sound OK then or split it around the middle??
Jet Eye Master
PX221 MHR, O tuned PX200, PX125 and some motorbikes
Joined: 14 Jun 2017
Posts: 2755
Location: London UK
Thu May 06, 2021 2:56 pm quote
I you can get 5mm off the crank, it will keep your options open for the future.
bodgemaster
63 GL, 76 Super (x 2), 74 Primavera (x 2), 06 Fly 150
Joined: 26 Sep 2013
Posts: 5831
Location: So Cal
Thu May 06, 2021 2:56 pm quote
Do it.
Ossessionato
1979 P150X, 1983 P200E, 1988 T5, 1995 PX200E, 2011 Yamaha Fazer 600 S2
Joined: 02 Aug 2015
Posts: 2261
Location: Veria, Greece
Sun May 09, 2021 5:17 am quote
Split and cut the crank today. Someone went a bit overboard with the grinding wheel at the factory (2nd photo). I think Jasil makes these??







Molto Verboso
2007 Stella 225
Joined: 02 Nov 2019
Posts: 1683
Location: Rochester, Minnesota
Sun May 09, 2021 5:27 am quote
SaFiS wrote:
Split and cut the crank today. Someone went a bit overboard with the grinding wheel at the factory (2nd photo). I think Jasil makes these??








This is the first time I've seen a crankshaft split on here. How do you get it back together and aligned?
Ossessionato
1979 P150X, 1983 P200E, 1988 T5, 1995 PX200E, 2011 Yamaha Fazer 600 S2
Joined: 02 Aug 2015
Posts: 2261
Location: Veria, Greece
Sun May 09, 2021 5:45 am quote
Hydraulic press for splitting and joining. Balancing block for balancing / alignment...

Ossessionato
1979 P150X, 1983 P200E, 1988 T5, 1995 PX200E, 2011 Yamaha Fazer 600 S2
Joined: 02 Aug 2015
Posts: 2261
Location: Veria, Greece
Thu May 13, 2021 1:40 pm quote
Crank is almost done. It has a 0,03mm play but I want to bring it to 0 (I know people that would consider the 0,03mm play acceptable). I had to buy a new dial indicator since my 5 year old nephew found our old one to be a nice toy. The plastic "glass" was broken, but the "mm" needle (small one) was closer to 0 instead of where it is now. Anyways, a few photos. Oh, and I think I'll weld the pin since I found the crank to be a bit "soft". It was easy to split it and align it, compared to other cranks we've done over the years...

Our old, German made DDR Keilpart Suhl dial indicator (we bought it from a Russian guy many years ago)...


Crank half in cases, balancing block and new, again German made, dial indicator...




Jet Eye Master
PX221 MHR, O tuned PX200, PX125 and some motorbikes
Joined: 14 Jun 2017
Posts: 2755
Location: London UK
Thu May 13, 2021 3:49 pm quote
Good idea welding the crank. Will help keep that valve pad shiny. And just about the only chance at keeping it at 0.00mm.
Where did the inlet timing end up?
Ossessionato
62 VBB1T Round Tail W/ leaner sidecar
Joined: 26 Jan 2019
Posts: 2241
Location: california
Thu May 13, 2021 4:17 pm quote
Impressive work Saf.

Crank web looks wider than stock.
What’s the width of the web here?



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