Wed Apr 28, 2021 4:42 am

Enthusiast
Vespa P125X
Joined: 30 Aug 2017
Posts: 70
Location: Dubai
 
Enthusiast
Vespa P125X
Joined: 30 Aug 2017
Posts: 70
Location: Dubai
Wed Apr 28, 2021 4:42 am linkquote
Hi all,

Always had great advice here so firstly thanks for that.

I have a 1978 P125x and a couple of years ago upgraded to a DR 177 with SIP Road 2.0, 24.24 Carb and air filter, bigger main jet etc. Also done the shocks, installed a front disc bake and SIP rims and tubeless tyres.

I am thinking of opening the cases to match the ports. Is this worth doing? Any advice?

Skimming or replacing the DR cylinder head?

If the engine is open what else should I do? Seals of course, any brand?

I have read to always replace the cruciform?

What about crank, clutch and a bigger toothed gear?

Do these thing materially affect performance?

It runs pretty well for a weeknd ride. But out here in Dubai it can get hot of course so need to think about overheating. I will be doing this for something to do over the hot summer months but dont really want to spend money on things which dont provide better performance.

Any advice greatly appreciated.
Wed Apr 28, 2021 5:28 am

Ossessionato
VSX, Stella 177, VNX1T, V9B1T
Joined: 20 Jul 2018
Posts: 3191
Location: Staten Island, NY
 
Ossessionato
VSX, Stella 177, VNX1T, V9B1T
Joined: 20 Jul 2018
Posts: 3191
Location: Staten Island, NY
Wed Apr 28, 2021 5:28 am linkquote
Well worth it, but you will need to spend a lot of time up jetting and I'd imagine the heat there would be quite something to deal with on a two stroke tuned engine.

Good luck! Looking forward to see how you fare with this. Minimal costs but big gains. You could also shift the port timing to gain some extra power if all you did previously was slap it on pnp with the gaskets it came with.

If you start posting images and numbers for what you are working on, other will chime in with suggestions.
Wed Apr 28, 2021 5:35 am

Molto Verboso
2007 Stella 225
Joined: 02 Nov 2019
Posts: 1748
Location: Rochester, Minnesota
 
Molto Verboso
2007 Stella 225
Joined: 02 Nov 2019
Posts: 1748
Location: Rochester, Minnesota
Wed Apr 28, 2021 5:35 am linkquote
Measure the squish to know if you can skim the cylinder head. My DR 177 had a huge squish 2.5+mm, I skimmed it down to about ~1mm with no issues.

I could over gear mine just changing the clutch gear, didn't need to change anything internally. I liked the higher 1,2,3 but couldn't pull a higher 4th gear and would slow down in a wind or on small hill, was nice on a flat road. If I were opening my case I would try a lower 4th gear to close the ratio between 3rd and 4th. Then try a higher clutch gear again.
Wed Apr 28, 2021 5:45 am

Ossessionato
VSX, Stella 177, VNX1T, V9B1T
Joined: 20 Jul 2018
Posts: 3191
Location: Staten Island, NY
 
Ossessionato
VSX, Stella 177, VNX1T, V9B1T
Joined: 20 Jul 2018
Posts: 3191
Location: Staten Island, NY
Wed Apr 28, 2021 5:45 am linkquote
I agree with Christopher, i have stock 4th gear and next time i open cases I'll go to a short 4th cause i need to keep rpms over 6000 or i lose all speed. Especially on windy days.

I also went from 1.25mm squish down to 0.8mm. it seems to have caused my jetting to get leaner. What was bogging at 135 main jet is now not bogging at 138 and possibly 140. So I've had to up jet 5-8 points. But it definitely evened out the jetting across the throttle range where before i always felt i could dial in one spot on the throttle range but not the rest. On the tighter squish, it feels better across the whole throttle range.
Wed Apr 28, 2021 7:10 am

Hooked
PX
Joined: 28 May 2020
Posts: 146
Location: Bognor Regis
 
Hooked
PX
Joined: 28 May 2020
Posts: 146
Location: Bognor Regis
Wed Apr 28, 2021 7:10 am linkquote
I have the same rig as you accept my px125 is a 2003 model. The difference between mine and yours, unless you have upgraded it, is i have a cosa clutch with 21/68 as standard ratio. Its the difference of about 6% top end over the earlier model. Sure is easier on the left wrist with lighter cosa clutch. I had a 79 Px 125 that was a lot slower than the one ive got now when it was a 125. About 5mph difference so dont know if anything else other than the clutch impacts the speed on earlier models.

I have dr177, 24mm and sip road 2.0, its all bolted on and pulls like a train with max speed on gps 64.5 mph, but man does it scream the revs of it. I guess a clutch cog change to 22 would mean not so many revs but as most of my drives are bursty runs on 40/50mph roads in UK cant help thinking i might regret changing the cog as its setup to do the job i need. I like the ability to overtake as it is. I also like the idea i can easily reverse the setup having not had anything dremelled off as in the UK a learner driver can only drive up to a 125cc and 125cc scooters are easier to sell to newbies over here.

Good luck with your project and look forward to hearing what you do and the results you get with it. Dubai, is it true that even the locals go away in the summer as the heat is unbearable, crazy 45+ centigrade?
Sat May 01, 2021 6:21 am

Enthusiast
Vespa P125X
Joined: 30 Aug 2017
Posts: 70
Location: Dubai
 
Enthusiast
Vespa P125X
Joined: 30 Aug 2017
Posts: 70
Location: Dubai
Sat May 01, 2021 6:21 am linkquote
Cheers
Gents, thanks for chipping in. Its much appreciated. ill take a look and do a bit more hoework. Ar there any good threads on here with regards reducing squish that you can direct me to.

I like the clutch idea as I think its on its way out anyway.

Mine pulls well in 3rd and I really want the ability to vertake rather than top end.

Yes, its gets to 45+. Its hot here already and been above 41 last week. Although we had or last scooter club ride out yesterday and it wasnt too bad.
Sat May 01, 2021 6:26 am

Enthusiast
Vespa P125X
Joined: 30 Aug 2017
Posts: 70
Location: Dubai
 
Enthusiast
Vespa P125X
Joined: 30 Aug 2017
Posts: 70
Location: Dubai
Sat May 01, 2021 6:26 am linkquote
A photo from our run out yesterday



Sat May 01, 2021 6:32 am

Ossessionato
76 Sprint V, 63 GL, 62 VBB, 05 Stella
Joined: 16 Jun 2011
Posts: 3340
Location: Nashville
 
Ossessionato
76 Sprint V, 63 GL, 62 VBB, 05 Stella
Joined: 16 Jun 2011
Posts: 3340
Location: Nashville
Sat May 01, 2021 6:32 am linkquote
Off the top of my head, I can think of four ways to reduce squish in your situation, depending on a number of variables. Most of these may be more adventurous than you're really looking for, but you asked

The most straightforward way would be to have the head or cylinder milled down. That means finding a machinist who can do it.

You can also do the head yourself by lapping with emery paper for a looooong time, like 20 minutes or so. I've taken that route a few times and now have a collection of DR heads of varying heights.

You could also put in a 60mm crank, then use base and head gaskets to get the desired port timing and squish. That's become my preferred route.

Finally, you could increase your port timings with a base gasket, then get a BGM177 head which seats down into the cylinder and use head spacers to adjust squish that way. That's what I did, in combination with a 60mm crank, on my VBB, and it works well.
Sat May 01, 2021 7:23 am

Hooked
PX
Joined: 28 May 2020
Posts: 146
Location: Bognor Regis
 
Hooked
PX
Joined: 28 May 2020
Posts: 146
Location: Bognor Regis
Sat May 01, 2021 7:23 am linkquote
craigyc wrote:
A photo from our run out yesterday
Fabulous pic. Thatís the first Dubai scooter club pic Iíve seen, great!
Sat May 01, 2021 7:46 am

Enthusiast
Vespa P125X
Joined: 30 Aug 2017
Posts: 70
Location: Dubai
 
Enthusiast
Vespa P125X
Joined: 30 Aug 2017
Posts: 70
Location: Dubai
Sat May 01, 2021 7:46 am linkquote
ferriswolf wrote:
I have the same rig as you accept my px125 is a 2003 model. The difference between mine and yours, unless you have upgraded it, is i have a cosa clutch with 21/68 as standard ratio. Its the difference of about 6% top end over the earlier model. Sure is easier on the left wrist with lighter cosa clutch. I had a 79 Px 125 that was a lot slower than the one ive got now when it was a 125. About 5mph difference so dont know if anything else other than the clutch impacts the speed on earlier models.

I have dr177, 24mm and sip road 2.0, its all bolted on and pulls like a train with max speed on gps 64.5 mph, but man does it scream the revs of it. I guess a clutch cog change to 22 would mean not so many revs but as most of my drives are bursty runs on 40/50mph roads in UK cant help thinking i might regret changing the cog as its setup to do the job i need. I like the ability to overtake as it is. I also like the idea i can easily reverse the setup having not had anything dremelled off as in the UK a learner driver can only drive up to a 125cc and 125cc scooters are easier to sell to newbies over here.

Good luck with your project and look forward to hearing what you do and the results you get with it. Dubai, is it true that even the locals go away in the summer as the heat is unbearable, crazy 45+ centigrade?
On the cosa clutch you mention 21/68. I had a quick look on the SIP website and it suggests a 20 or 22 tooth clutch cog for a 125 engine, or change the primary gear to match the clutch cog. Any other advice on this? Go for a 20 or 22? Or go for a 21 and change the primary gear? Cheers.
Sat May 01, 2021 7:49 am

Enthusiast
Vespa P125X
Joined: 30 Aug 2017
Posts: 70
Location: Dubai
 
Enthusiast
Vespa P125X
Joined: 30 Aug 2017
Posts: 70
Location: Dubai
Sat May 01, 2021 7:49 am linkquote
chandlerman wrote:
Off the top of my head, I can think of four ways to reduce squish in your situation, depending on a number of variables. Most of these may be more adventurous than you're really looking for, but you asked

The most straightforward way would be to have the head or cylinder milled down. That means finding a machinist who can do it.

You can also do the head yourself by lapping with emery paper for a looooong time, like 20 minutes or so. I've taken that route a few times and now have a collection of DR heads of varying heights.

You could also put in a 60mm crank, then use base and head gaskets to get the desired port timing and squish. That's become my preferred route.

Finally, you could increase your port timings with a base gasket, then get a BGM177 head which seats down into the cylinder and use head spacers to adjust squish that way. That's what I did, in combination with a 60mm crank, on my VBB, and it works well.
Thats great advice thanks. For my first go at tuning I might just stick with option 1! I'll measure the squish as it is and see where we go from there. Appreciated.
Sat May 01, 2021 7:53 am

Enthusiast
Vespa P125X
Joined: 30 Aug 2017
Posts: 70
Location: Dubai
 
Enthusiast
Vespa P125X
Joined: 30 Aug 2017
Posts: 70
Location: Dubai
Sat May 01, 2021 7:53 am linkquote
ferriswolf wrote:
craigyc wrote:
A photo from our run out yesterday
Fabulous pic. Thatís the first Dubai scooter club pic Iíve seen, great!
Thanks. We have over 200 members and try and get out every other week when the weather allows. Check out the facebook page. Plenty more photos and a couple of good videos.

https://www.facebook.com/groups/TheDVLC/

Dubai Vespa and Lambretta Club
Sat May 01, 2021 10:25 am

Hooked
PX
Joined: 28 May 2020
Posts: 146
Location: Bognor Regis
 
Hooked
PX
Joined: 28 May 2020
Posts: 146
Location: Bognor Regis
Sat May 01, 2021 10:25 am linkquote
Re: Cheers
craigyc wrote:
Gents, thanks for chipping in. Its much appreciated. ill take a look and do a bit more hoework. Ar there any good threads on here with regards reducing squish that you can direct me to.

I like the clutch idea as I think its on its way out anyway.

Mine pulls well in 3rd and I really want the ability to vertake rather than top end.

Yes, its gets to 45+. Its hot here already and been above 41 last week. Although we had or last scooter club ride out yesterday and it wasnt too bad.
You should have plenty of power in your kit to do Safe overtakes on 50mph cars, safe as in passing and returning to lane with confidence. My 3rd to 4th gear is extremely responsive and on my dr177 this is when the power kicks in. So always keen to get in 4th as soon as possible. It reaches genuine 60 mph from 50mph very quickly then I start to rev out at 64. I will be having a 22 tooth sip clutch done this summer and having engine split to change seals and anything else routine maintenance. I won't be having any other upgrades done as I think mine is at its optimum point for reliability and it achieved what I need. So the clutch mod is definitely cheap option for you. As to your question about clutch cog versus primary ido not know what configuration you have in your px. I'm sure others in here will know the factory setup for that year. Scooterhelp website has a px gearing calculator you could look at. My scooter is a 2005 MY model 21/68 as standard, confirmed by an email I sent to sip. I believe you can go 1 eitger side of this 20 or 22 to mesh with standard primary. But as to yours you need to confirm the options. In my case sip recommended to me a 22. I rev out with a 21 so 22 seems logical for dropping revs and putting a few mph on top, this of course will be marginal. Dropping the revs and getting same speed i had before is my aim here whilst not overdoing things.
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Sat May 01, 2021 9:08 pm

Ossessionato
79 P200E, 62 Allstate, 2008 Stella
Joined: 11 Jan 2006
Posts: 2172
Location: Florence, OR
 
Ossessionato
79 P200E, 62 Allstate, 2008 Stella
Joined: 11 Jan 2006
Posts: 2172
Location: Florence, OR
Sat May 01, 2021 9:08 pm linkquote
craigyc wrote:
A photo from our run out yesterday
Thanks for the photo craig - it's awesome!
Sat May 01, 2021 10:35 pm

Jet Eye Master
PX221 MHR, O tuned PX200, PX125 and some motorbikes
Joined: 14 Jun 2017
Posts: 2817
Location: London UK
 
Jet Eye Master
PX221 MHR, O tuned PX200, PX125 and some motorbikes
Joined: 14 Jun 2017
Posts: 2817
Location: London UK
Sat May 01, 2021 10:35 pm linkquote
Re: Cheers
ferriswolf wrote:
My scooter is a 2005 MY model 21/68 as standard, confirmed by an email I sent to sip.
Unless you have counted the actual teeth on your cog, or have a Friday special from the factory, I would be quite sure it's 20/68 on 2003 PX125.
20, 21 & 22 all fit your 68. Can even get a DRT 23 that fits.

Craigyc, as CM said option 3, fit a 60mm crank. This fixes everything in one go. Corrects the squish and ups the port timing. if you have a non stock exhaust all will be fine. Be sure primary is at least 21/68, 22/68 with the 60mm crank. Fit the best clutch in your budget.

Struggling to believe there are so many scooters in Dubai. Pretty cool.
Mon May 03, 2021 9:37 pm

Addicted
'66 Super 150
Joined: 11 Jul 2017
Posts: 789
Location: MN
 
Addicted
'66 Super 150
Joined: 11 Jul 2017
Posts: 789
Location: MN
Mon May 03, 2021 9:37 pm linkquote
Really sweet pic of your group!

Which Vespa are you?
Mon May 10, 2021 9:25 pm

Enthusiast
Vespa P125X
Joined: 30 Aug 2017
Posts: 70
Location: Dubai
 
Enthusiast
Vespa P125X
Joined: 30 Aug 2017
Posts: 70
Location: Dubai
Mon May 10, 2021 9:25 pm linkquote
Kimono32 wrote:
Really sweet pic of your group!

Which Vespa are you?
I'm the white one, second from left. Most others are later P2's. Although 150 special in there as well.
Sat May 15, 2021 1:31 am

Enthusiast
Vespa P125X
Joined: 30 Aug 2017
Posts: 70
Location: Dubai
 
Enthusiast
Vespa P125X
Joined: 30 Aug 2017
Posts: 70
Location: Dubai
Sat May 15, 2021 1:31 am linkquote
Cosa Clutch
Regarding the cosa clutch. Which would you suggest 20/68 or 22/68.

Also any specific manufacturer. The SIP stuff I have bought I have always liked. Any others?
Sat May 15, 2021 4:38 am

Hooked
PX
Joined: 28 May 2020
Posts: 146
Location: Bognor Regis
 
Hooked
PX
Joined: 28 May 2020
Posts: 146
Location: Bognor Regis
Sat May 15, 2021 4:38 am linkquote
Re: Cosa Clutch
craigyc wrote:
Regarding the cosa clutch. Which would you suggest 20/68 or 22/68.

Also any specific manufacturer. The SIP stuff I have bought I have always liked. Any others?
I guess it depends on what type of driving you intend to do, are you going on longer touring trips where revving the tits out of your current setup is very tiring running at rev out in 4th, or are you just doing bursty runs, 10 - 20 mph run outs with your mates at the weekend etc?
Sat May 15, 2021 4:49 am

Enthusiast
Vespa P125X
Joined: 30 Aug 2017
Posts: 70
Location: Dubai
 
Enthusiast
Vespa P125X
Joined: 30 Aug 2017
Posts: 70
Location: Dubai
Sat May 15, 2021 4:49 am linkquote
its mostly in and around town at weekends. No long runs and not after top end as a crap myself above 90km/h. Usually happy to sit at 80km/h but would love some torque between 50-80 ish.
Sat May 15, 2021 4:58 am

Hooked
PX
Joined: 28 May 2020
Posts: 146
Location: Bognor Regis
 
Hooked
PX
Joined: 28 May 2020
Posts: 146
Location: Bognor Regis
Sat May 15, 2021 4:58 am linkquote
craigyc wrote:
its mostly in and around town at weekends. No long runs and not after top end as a crap myself above 90km/h. Usually happy to sit at 80km/h but would love some torque between 50-80 ish.
Well in that case IMO the lower cog then, the gearing will be shorter and more fun with your kitting for burst runs, overtakes.
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