O-tuning Bogging problem
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Member
PX200
Joined: 14 Aug 2019
Posts: 17
Location: ISTANBUL
Wed Aug 14, 2019 2:40 am quote
Hello everyone

My bike is 94my PX200.
Iíve done engine rebuilt with o-tuning. Enlarged Port and polish , spaco 26/26si with autolube mainjet 120. 68mm piston. Flowed 57 stroke chrankshaft and cylinder head is skimmed 2 mm. Squish gap is 2mm or 2.30mm , İgnation time is standart 23 degree. Gianelli expansion chamfer type exhaust. My problem is bogging at low revs. First start and idle perfect but after 5 minutes riding problem starting My bike run high rpm (3/4 throttle and full throttle ) very well but when I want to stop for traffic lights engine bogging and stop in 5 seconds. And the other hand too much and splatter burnt black gunk oil is coming out the end of exhaust stub and exhaust clamp. I need your suggestions.

Where should I start ignation , air or oil suck , jetting ?
Member
PX200
Joined: 14 Aug 2019
Posts: 17
Location: ISTANBUL
Wed Aug 14, 2019 10:45 am quote
Ezel wrote:
Hello everyone

My bike is 1994 PX200.
Iíve done engine rebuilt with o-tuning.
Enlarged Port and polish
spaco 26/26si with autolube mainjet 120.
68mm piston.
Flowed 57 stroke chrankshaft Cylinder head is skimmed 2 mm. Squish gap is 2mm or 2.30mm. Ignition time is standart 23 degree. Gianelli exhaust ( not box type ). My problem is bogging at low revs. First start and idle perfect but after 5 minutes riding problem is start. My bike run high rpm (3/4 throttle and full throttle ) very well but when I want to stop for traffic lights or wnt ride low rev engine bogging and stop in 5 seconds. And the other hand too much splatter burnt black gunk oil is coming out the end of exhaust stub and exhaust clamp.
Kicsktart is slightly hard but working.
I need your suggestions.

Where should I start ignition , oil suck or jetting ?
Veni, Vidi, Posti
74 50s x2 78 P200 84 Cosa 58 AllState 68 Sprint 80 50special + projects
Joined: 22 Nov 2010
Posts: 6996
Location: seattle/athens
Wed Aug 14, 2019 4:26 pm quote
What does your plug look like?

"Kickstart is slightly hard but working. " Do you mean that there's a lot of resistance to rotating when you kick it or do you mean that it is difficult to start up the motor but it spins as it should?
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Old douglas ..smallie with polini 115..super with nasco 177
Joined: 07 Nov 2013
Posts: 549
Location: New Zealand
Wed Aug 14, 2019 4:49 pm quote
Retard the timing to 18BTDC
Turn the stator clockwise to retard the timing to 18. Check with a strobe. Should be a screamer after that.. May have to dremmel the slots a bit to get the required rotation.
good luck
Member
PX200
Joined: 14 Aug 2019
Posts: 17
Location: ISTANBUL
Wed Aug 14, 2019 10:50 pm quote
V oodoo wrote:
What does your plug look like?

"Kickstart is slightly hard but working. " Do you mean that there's a lot of resistance to rotating when you kick it or do you mean that it is difficult to start up the motor but it spins as it should?
kickstart hard than standart but first kick or second kick start normally.
Member
PX200
Joined: 14 Aug 2019
Posts: 17
Location: ISTANBUL
Wed Aug 14, 2019 10:52 pm quote
Bluecati wrote:
Turn the stator clockwise to retard the timing to 18. Check with a strobe. Should be a screamer after that.. May have to dremmel the slots a bit to get the required rotation.
good luck
I will do today if l solved l write here. I hope this problem only ignition timing.
Member
PX200
Joined: 14 Aug 2019
Posts: 17
Location: ISTANBUL
Wed Aug 14, 2019 11:02 pm quote
Last night I wathed youtube video

İtís about gearbox oil suck can cause blowback..

İs blowback cause bogging until stop at low revs ?

And the other hand my bikes idle and high revs perfect first start perfect.

Low and middle rpm goes bogging until stop.

This is very confused.
Enthusiast
Joined: 14 Jun 2016
Posts: 86
Location: Macedonia
Thu Aug 15, 2019 3:09 am quote
You should really start with retarding the timing to 18degrees as bluecati said!

I would check if your choke closes all the way. remove the airbox lid and try to see.

Then if you still have a problem you can start changing jets to find the best setup.

It would be helpful if you check all the jets and report here.

Or take pictures of all the numbers on all the jets.
Member
PX200
Joined: 14 Aug 2019
Posts: 17
Location: ISTANBUL
Thu Aug 15, 2019 4:26 am quote
jocco wrote:
You should really start with retarding the timing to 18degrees as bluecati said!

I would check if your choke closes all the way. remove the airbox lid and try to see.

Then if you still have a problem you can start changing jets to find the best setup.

It would be helpful if you check all the jets and report here.

Or take pictures of all the numbers on all the jets.
Jets BE3 air 160 - pilot 55/160 main 120
Member
PX200
Joined: 14 Aug 2019
Posts: 17
Location: ISTANBUL
Thu Aug 15, 2019 4:30 am quote
I cant remove flywheel for timing because I dont have removal tool.. tomorrow l will go vespa specialist..
Member
PX200
Joined: 14 Aug 2019
Posts: 17
Location: ISTANBUL
Thu Aug 15, 2019 4:31 am quote
Spark plug totaly black and little oily..
Molto Verboso
Joined: 26 Oct 2015
Posts: 1570

Thu Aug 15, 2019 6:45 am quote
Ezel wrote:
jocco wrote:
You should really start with retarding the timing to 18degrees as bluecati said!

I would check if your choke closes all the way. remove the airbox lid and try to see.

Then if you still have a problem you can start changing jets to find the best setup.

It would be helpful if you check all the jets and report here.

Or take pictures of all the numbers on all the jets.
Jets BE3 air 160 - pilot 55/160 main 120
A 120 main sounds way too small to me. I would think that will all your mods, you'd need closer to a 128 or 130. I would also think that bringing your timing back to 18 degrees would be way too much for a semi-stock top end. Usually 18 degrees are recommended for just the performance cylinders. I probably wouldn't keep it at 23 degrees with the modern fuels though. I'd say try adjusting it to around 21-22 degrees. I would think that 18 degrees would make it even more boggy at the low end.

I'd start out by cleaning your carb and jets out really well (it's the cheapest and fastest thing to do). Maybe you have a partial blockage in there? If it's not that, I'd almost think that sounds like a possible air leak.
Member
PX200
Joined: 14 Aug 2019
Posts: 17
Location: ISTANBUL
Thu Aug 15, 2019 10:55 am quote
whodatschrome wrote:
Ezel wrote:
jocco wrote:
You should really start with retarding the timing to 18degrees as bluecati said!

I would check if your choke closes all the way. remove the airbox lid and try to see.

Then if you still have a problem you can start changing jets to find the best setup.



It would be helpful if you check all the jets and report here.

Or take pictures of all the numbers on all the jets.
Jets BE3 air 160 - pilot 55/160 main 120
A 120 main sounds way too small to me. I would think that will all your mods, you'd need closer to a 128 or 130. I would also think that bringing your timing back to 18 degrees would be way too much for a semi-stock top end. Usually 18 degrees are recommended for just the performance cylinders. I probably wouldn't keep it at 23 degrees with the modern fuels though. I'd say try adjusting it to around 21-22 degrees. I would think that 18 degrees would make it even more boggy at the low end.

I'd start out by cleaning your carb and jets out really well (it's the cheapest and fastest thing to do). Maybe you have a partial blockage in there? If it's not that, I'd almost think that sounds like a possible air leak.
Maybe you are right but fuel is fresh and modern 97 octane.. beed speed say 18 degree is ok for modern fuels. I want to tryin less then 23 degree.

My carb is new. I am controlled but not l am not cleaning.

All engine parts new gaskets seals all new.

Monday I am go to PX different specialist for engine re-rebuild. I am take a picture and post here.

l think this is air leak you are probably right.
Member
PX200
Joined: 14 Aug 2019
Posts: 17
Location: ISTANBUL
Thu Aug 15, 2019 11:04 am quote
My bike[/img]

F97DE20A-632A-41DE-8AF5-5B77AF79915A.jpeg

Member
PX200
Joined: 14 Aug 2019
Posts: 17
Location: ISTANBUL
Thu Aug 15, 2019 11:09 am quote
Before machined rotary pad...

This is laser weld , not tig weld..

Tig weld is dangerous for aluminum because too hot. Hot can cause bending on aluminum.

2A7D003F-D95E-4482-B332-BE62BDA6CE12.jpeg

Member
PX200
Joined: 14 Aug 2019
Posts: 17
Location: ISTANBUL
Thu Aug 15, 2019 11:15 am quote
2 mm skimmed and polished head...

988E0910-D2A1-42B1-AC0C-356F18A96031.jpeg

Member
PX200
Joined: 14 Aug 2019
Posts: 17
Location: ISTANBUL
Thu Aug 15, 2019 11:35 am quote
Port and polished engine case..
I am port polish and match carb, carb case and air inlet but l forget take a picture.

These are old pics. I will upload new pics on monday from specialist.

Today when engine work in short time my speedo show 65 km/h in 2. Gear. Is this good or normal l dont know ?

Have a nice riding...

DD75792E-8995-4926-9D41-D7A8A82F6102.jpeg

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GL, PK, PE200
Joined: 24 Apr 2012
Posts: 640
Location: Deep in the heart of Texas
Thu Aug 15, 2019 11:44 am quote
With the o tune was the carb box open to match the carb? Was the inlet open to match the carb box? A 26/26 carb is not really needed for your set up and can take a while to tune. Definitely not plug and play. I would imagine this was done but just going down known issues with 26/26 carbs.
Member
PX200
Joined: 14 Aug 2019
Posts: 17
Location: ISTANBUL
Thu Aug 15, 2019 12:13 pm quote
rowdyc wrote:
With the o tune was the carb box open to match the carb? Was the inlet open to match the carb box? A 26/26 carb is not really needed for your set up and can take a while to tune. Definitely not plug and play. I would imagine this was done but just going down known issues with 26/26 carbs.
http://modernvespa.com/forum/topic87680.2
Member
PX200
Joined: 14 Aug 2019
Posts: 17
Location: ISTANBUL
Thu Aug 15, 2019 12:32 pm quote
rowdyc wrote:
With the o tune was the carb box open to match the carb? Was the inlet open to match the carb box? A 26/26 carb is not really needed for your set up and can take a while to tune. Definitely not plug and play. I would imagine this was done but just going down known issues with 26/26 carbs.
I want to learn my ability and skill.
These mods only trying and learn.
I am 28 years old. I love PX and this bike is not my first PX.
I want to malossi 221 mhr on last summer and I will go to the professionel specialist. Generally I am tune my cars. Thank you for your suggestions.
Molto Verboso
Joined: 26 Oct 2015
Posts: 1570

Thu Aug 15, 2019 4:53 pm quote
rowdyc wrote:
With the o tune was the carb box open to match the carb? Was the inlet open to match the carb box? A 26/26 carb is not really needed for your set up and can take a while to tune. Definitely not plug and play. I would imagine this was done but just going down known issues with 26/26 carbs.
Oh, I missed that it was a 26/26. I donít know which main jet for that carb. I bought one new years ago, tried to get it tuned in, then realized it wasnít going to happen. Itís sitting in my shelf gathering dust along with the other failed performance adding bits that failed to deliver.
Member
PX200
Joined: 14 Aug 2019
Posts: 17
Location: ISTANBUL
Thu Aug 15, 2019 10:26 pm quote
whodatschrome wrote:
rowdyc wrote:
With the o tune was the carb box open to match the carb? Was the inlet open to match the carb box? A 26/26 carb is not really needed for your set up and can take a while to tune. Definitely not plug and play. I would imagine this was done but just going down known issues with 26/26 carbs.
Oh, I missed that it was a 26/26. I donít know which main jet for that carb. I bought one new years ago, tried to get it tuned in, then realized it wasnít going to happen. Itís sitting in my shelf gathering dust along with the other failed performance adding bits that failed to deliver.
My real reason of choose 26/26 for autolube system. Because l am drive daily in summer. And I dont want to extra effort every refueling.

Yes it dont any different 24/24 but pinosco si 30/30 is utopia...
Molto Verboso
1979 P150X, 1983 P200E, 1987 T5, 1996 PX200E, 2011 Yamaha Fazer 600 S2
Joined: 02 Aug 2015
Posts: 1526
Location: Veria, Greece
Thu Aug 15, 2019 10:45 pm quote
Anything bigger than the SI24 is a waste of money. A dialed in 24 is equal to a PHBH30. The 26 is just a rebored 24 and impossible to dial in. The 28/30 from Pinasco are just a joke. Go back to the 24 and it will probably work better if your problem is not related to seals. I have a longstroked O-Tuned PX and the 24 works great. I tried a 26 I also had on the self and it was crap...
Hooked
Honda elite
Joined: 19 Jun 2007
Posts: 499
Location: California
Fri Aug 16, 2019 2:54 am quote
Looks good ezel the welding is interesting do you have a photo after machining?
Member
PX200
Joined: 14 Aug 2019
Posts: 17
Location: ISTANBUL
Fri Aug 16, 2019 1:07 pm quote
hibbert wrote:
Looks good ezel the welding is interesting do you have a photo after machining?
My friend really I dont have any pictures after machining because when we want start to machining we cant put in cnc because is too big , so we put in classic big old lathe machine , adjust to true clerances and true radius is painfull and stressfull , we cant use any technology for machining. Maybe work on 3 hours.. 1 micron skim and try 1 , micron skim and try. I forget take a picture. I was very stressed l am really sorry..
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