Hello, Im new here I have Gilera RCR 50(same as derbi senda) and i've got problem with it... 2 months a go i changed piston and rings becous i had no oil and you know what happend with it cylinder was ok and it look very nice, like new one The problem is that my Senda go only 65 Km/h its like 32 mp/h ? and it should go 80 Anyone have any idea ? I dont have any blocking things now(tell me how its called,thing that blocks moto to 45 km/h cuz my english is poor ) I have 75 Main jet and needle jet is on high or low position? i know that its for more fuel And 1 more question, mby any of you have picture of a block on Exhaust in derbi senda? old owner sad that its not blocked but i dont know how blocks on exhaust looks and where it is.. I asked a lot of people why my gilera going only 65 km/h but no one know it also lose some power when i ride more but i think its normal ? or not? I beg you for help and thank you!
double check the exhaust by removing the flange bolts and the bolt through the bracket which secures the front pipe to the frame and look inside the exhaust it should be nice and smooth down the pipe and wide so you can get a finger inside the pipe easily, a restricto will be a little cone shaped piece of metal or a simple washer tack / spot welded to the insides of the pipe whats your gear ratio? count the teeth on both sprockets and compare them to a bike info guide on the internet, to gain a bit more speed start by increasing a tooth on the front sprocket however you will loose a bit of acceleration due to a bigger gear ratio, also check to see the inlet manifold or the airbox isnt retricted by any steel plates (however ive only seen these common on chinese bikes not many euro ones) check also the throttle slide opens to clear the airway inside the carb (the venturi i think its called, by removing the airbox and giving the bike full throttle (when switched off) and see if the throttle slide disappears showing just the needle try the above and check these also whats the pull off like and accelaration, does the bike splutter at all or fail to rev properly sumtimes? also - what was the bike like before you changed the piston, before it seized?
Ok,thanks a lot for help i talked with some people and they also said that it gona be exhaust fault.. i forgoten to say that like 2 months i was riding with a lot more oil then i should have in fuel.. like 200 ml of oil to 5 L to fuel.. I give u short history of my gilera I wasnt fliping oil to the thing that mix it with fuel and it crashed(sorry for my english) but before i knew it i filled it with oil and i also was filing oil to the fuel so i had something like 200 ML of oil to 5 L of fuel and i was riding like it 4 months, piston in my moto crashed 3 days after i unblocked my moto and when i gived in 75 jet... It was riding 3 days and it was like flying i was very happy, i didnt knew v-max but it has great acceleration and 3 days after it friends said that i havent got to fill oil to the fuel cuz its enough in the machine that mix it and i have done it and in 1 day something like shooted, exhaust was very silence and moto have lost power.. then 1month about riding on the slow moto piston crashed and the thing that piston is on (not cylindeR) i changed all and my moto is like i sad at begining ;P its slow So you are sure that its exhaust fault? and thanks for every answer :emb:
if that is all the bike did before it's beacuse it's gearing is still restricted if its just started doing this it sounds like your cylinder may be damaged, derbi ones are nicasiled so any pickup from the piston will score it and leavew you with a lack of power. do a compression test, you should get over 80PSI if compression is ok, it could be a problem with the mains/big-end, possibly due to lack of oil.
Hey,again compression is good and cylinder isnt damaged and im 100% sure i seen cylinder like 2 weeks a go and it was like new compression is also very good we count it in other thing and it was OK
daft as it sounds, you did put the piston in the right way? the little arrow points towards the exhaust side of the cylinder. done that before :emb: it could be one of many things. does the engine sound right? sometimes they sound off when they arent producing the power they should do.
Damn, they history i said was like 2 months a go and i fixed scooter, piston has arrow to the exhaust, everything is good.. engine sounds like it was when i bought it and everything was ok. I only got problem with low v-max and acceleration when engine heat.. but its not problem with piston.. i got orginal derbi one and i allways heat moto before i ride sometiems he lose much power but sometimes its like as on cold engine but still v-max and acceleration isnt very good.. Btw: i would like J-nitro to reply rly as i said its ok with engine i seen everything when we was fixing it and i knew about arrow at piston
lol if wobbly cant solve this problem for you i doubt i can mate , chris (wobbly) has been in this game longer than me buddy but anyway, first off i thought it may be something to do with the piston but i didnt ask because i knew it wouldnt fit in the barrel properly and would last a few minutes like i did to my old aerox (we've all done it LOL) right sounds so me like its been fitted ok though if its working fine etc... but im sure ive read somewhere its sluggish right? could be because of two reasons mate oil/lubrication - the ideal perfect 2 stroke in my book would be an engine with out oil as it affects the burn inside the engine, i.e more oil you use the less responsive as the burn isnt so pure if you get me, but obvously a joker knows that in the real world every engine today needs oil, thing is it needs to be added in the right amount otherwise itll seize like whats happend before to you or on the other side of the coin the engine misfires and becomes really sluggish and accelerates like a slug (too much oil) as the petrol/air mix is too contaminated you need to mix your oil and petrol/gas in the right amount which is usually about 50:1 , 50 parts of fuel, 1 part oil or in laymans terms 1 L (1 litre of petrol to 20mls of oil - (4 teaspoons) ) thats a nice mixture for a scooter and it will run nice an responsive - only other problem you may have if some ones been dicking around with it is your carb, check all the brass jets inside the float bowl , hold them all up to the light you should be able to see daylight through EVERY single one check the float operates properly moves easily, the pin is in it and the fuel valve which lets fresh fuel in the carb moves properly when the float is moved around. once youve done this reset the carb to its factory built settings and play about with it whilst the engine is running the air/mixture screw should be set at roughly all the way in (screwed all the way in) and wound out about 2 and a 1/2 turns if the pull of is shit and spluttery give it some more air and wind the air screw out half a turn till it feels nice and quite responsive obv play about with the idle screw until it idles in neutral ok WHEN WARM - not cold as this is not a true indication of the engines performance when cold look at the guides section and read about MiNoR CoNfUsIoN's guide on here about carb's (carburettors for a better understanding of how to tweak with them a carb that is not set properly will play hell and downgrade the engines performance so check that the two issues above are ok and report back and tell us whats happening j-nitro
Hello, thanks for your posts and help I have riden without a silencer and motor is like new! acceleration is great and v-max atm is 70.. but i think when i clean exhaust it will be more only damn silencer gived me a lot on acceleration ;d
