Speedfight 3 2T AC reduced power even with new cilinder

[Joshua137]

Hello,
i did not change a lot of the scooter everything is original. Recently i changed the following things: cylinder and piston, air filter mat, vario weights (9g) and shoes, v-belt, start plug, electric starter and ignition coil.
Unforutnalty the scooter still doesnt have a lot of power... of course i am not going full speed because of the new cilinder but its clear that the power is not as it was originally. I am not sure that i set the screws in the carbunator right because there is not a big effect by turning them. Also when i give some gas and release the rotatitions of the engine only decrease slowly. Lastly, i recognied that there is not much air coming out of the exhaust...

Do you think i have to get a new exhaust or what do you think is the problem?

Thanks a lot in advance!

Post automatically merged: 21 May 2021

If there is anyone living in Leiden who is willing to have a look on the scooter or knows someone please refer me! I am happy to pay for the effort

 

[eurokit]

What cylinder and piston kit did you bought..

The cheapest kits are mostly not worth it. That because of low quality piston rings and poor finish of the cylinder

I would only recommend to go with the original stock peugeot cylinder. Its the best quality you get for the money.
Only it will costs higher.

 

[Sparky]

Can be that your exhaust is clogged and must be cleaned, especially with 2T.
Maybe this was the problem, with your decreasing power, in the first place!

I am not sure that i set the screws in the carbunator right because there is not a big effect by turning them. Also when i give some gas and release the rotatitions of the engine only decrease slowly.

Could be a case of "valse lucht", i don't know the right words for this in English or a case of very lean mixture.

With "valse lucht" i mean that somewhere, in a parasitic way, air is entering the combustion system.
Like leaking gaskets at your reedvalve or manifold or leaking carter oilseals or leaking vacuumhose of your petcock or open nippels of your carburator or a leaking connection between your carburator en your manifold or a leaking connection between jour airfilterhose and your carburettor inlet....

 

[eurokit]

Could be a case of "valse lucht"

Maybe bypassed air?

 

[Joshua137]

What cylinder and piston kit did you bought..

The cheapest kits are mostly not worth it. That because of low quality piston rings and poor finish of the cylinder

I would only recommend to go with the original stock peugeot cylinder. Its the best quality you get for the money.
Only it will costs higher.

I bought a kit (without head) from DMP which i got recommended from the previous owner. Do you think its possible to just change the piston rings?

Post automatically merged: 23 May 2021

Can be that your exhaust is clogged and must be cleaned, especially with 2T.
Maybe this was the problem, with your decreasing power, in the first place!


Could be a case of "valse lucht", i don't know the right words for this in English or a case of very lean mixture.

With "valse lucht" i mean that somewhere, in a parasitic way, air is entering the combustion system.
Like leaking gaskets at your reedvalve or manifold or leaking carter oilseals or leaking vacuumhose of your petcock or open nippels of your carburator or a leaking connection between your carburator en your manifold or a leaking connection between jour airfilterhose and your carburettor inlet....

It might be that the exhaust is clogged. Are there easy ways to test that? I've actually also been thinking about it because I read it in some forum but everyone I asked and seemed to have some kind of expertise said that they would not really think that that's the problem. I'm not sure why though.

Thanks also for the detailed description of the wrong air. I also checked that previously but I believe that might not have been inclusive enough. The reed valve (new) and manifold look fine (no damage and new seals). I also suspected that the connections from and to the carbonator might not be closing well so I bought some new clamps.



How do I test for those: leaking carter oilseals or leaking vacuumhose of your petcock or open nippels of your carburator?

Post automatically merged: 23 May 2021

I think there might indeed be something wrong within the carbonator. The other day I noticed that there was a bit of petrol in the air filter. Do you think thats because of the nipples?

 

[eurokit]

Thats what i already though. DMP is cheap shit. And its the best to avoid those cilinders. Sell it or throw it away..
Buy just the original Peugeot cilinder kit, and you will be good. Dont know where you are comming from.

But if you live in the netherlands i can provide you an URL where you could be the new cilinder.

Peugeot horizontal Air cooled you can find it here (as an example)

EasyParts.nl - Cilinderkit Ø40 PEUGEOT horizontaal 50 AIR 2T E2 (C-Tech) (Zonder pakkingen - Cilinders

Originele cilinder & zuiger voor Peugeot horizontaal (C-Tech) 50cc AIR 2-takt, Euro2 scooters type B1E40QMB-C, B1E40QMB. Wordt zonder pakkingen geleverd. Cilinderkit Ø40 PEUGEOT horizontaal 50 AIR 2T E2 (C-Tech) (Zonder pakkingen - Cilinders - Originele scooter onderdelen | Piaggio, Vespa...

www.easyparts.nl

Yes the difference on price is higher, but iam certain it would solve your engine problem.


The timing in the DMP cilinders are very poor, use a lot of gas and lacks power.

 

[Joshua137]

I'm not even 100% anymore that the cylinder was the problem. I noticed some scratches in the old cylinder but they might be normal. The performance did not really change by building in the new cylinder. I will post some foto's of the old cylinder. However, also with the original one the power decreased so either the old cylinder was broken or there must be another problem. Btw the compression was also quite low with the previous cylinder (4-5 bar) if the mechanic measured it right...

 

[eurokit]

Did you also checked for worn crankshaft seals?? If they going to sweat, then certainly there is something wrong there.

Did you also checked for blown gaskets?

Vertical scretches are not good on the piston and cylinder wall. Looks like you mixture was lean or just use limited on oil.

Of mixture was good, it wont end on scretches in the cylinder.

I would also check the Oil line filter between the oil tank and the oil pump.. Maybe its clogged up with residu.

Why the cylinder is damaged is due poor maintanance. If you did all changed it out for new it might even happend.

 

[Joshua137]

I checked the seals. They looked fine to me, what do you think?
I changed the gaskets when I changed the cylinder and I also changed the gaskets of the manifold.

I will have a look at the oil filter!

Yes, I can imagine. I did not drive the scooter really long, it was a little bit of a bad buy.

Post automatically merged: 23 May 2021

Thats only the seal on the vario side*