Help please

[Greavesy]

Ok guys and girls heres my problem, a friend of mine has a Peugeot speedfighter 2, the problem is that when he accelerates off the line he picks up speed as normal all the way to around 35-40mph, once reaching this top speed his engine seems to just give up it slowly slows down, and we have seen it drop down to about 20mph.
We have changed the belt and the clutch, and no difference. Any ideas on what could be the problem? Thanks Tom

[Mikey CB500]

have you checked the variator and rollers?

had the same problem when the big spring in the variator gave up in my malaguti phantom

due to it being weak and stretched it played up and would cause all sorts of belt related problems

[Greavesy]

Hey thanks for your reply, yes had it apart 6+times, gone through 3 belts as it keeps over heating and they just fall to pieces. Rollers were changed awhile back, so that he could gain more top end so put in some 9g rollers instead of the 7.5's. The big spring? are you on about the one in the clutch??

[Mikey CB500]

No its the large spring between the two variator plates, https://www.wemoto.com/bikes/Peugeot/Speedfight_AC-Rear_drum_50cc/98-00/picture/Variator_spring_-_kg._35_MAUVE

Cause it sounds like variator slipage at high rpm to me, would explain the heat and wear of the belt

[Greavesy]

The veriator is fine, clutch is fine, gear box checked and all is fine, new oil in gear box and engine. rollers and belt are all ok, new irridum spark plug and carb is clean and set up correctly, this is what makes it so confusing, things i can say are that, it smells very rich in petrol but has done since he had a 100cc carb put in over a year ago, after riding 200meters once stopped you have to open it up full throttle and wait a second of two before it actually moves. It also ticks over fine.

[Greavesy]

sorry, i said variator was fine, everything we have checked on it was fine, but ive just sent him the link with the spring to see if he has checked it. Cheers for your reply again

[Greavesy]

The spring, is in the clutch assembly as far as i am aware as well as my friend. We put a new whole clutch assembly in today. and it worked well for half hour. but then went back to normal.

[Greavesy]

The spring, is in the clutch assembly as far as i am aware as well as my friend. i dont know of another spring being in the variator other than under the kick start. We put a new whole clutch assembly in today. and it worked well for half hour. but then went back to normal.

[Mikey CB500]

Now you say it smells rich and takes a couple of seconds to pull of the line possibly hes overfueled it dramaticaly putting the 100cc carb on it and its bogging

Could cause the vairiator to slip if the revs cut down too quickly due to bogging.

Think you could get a video of what it does? May help if we can see/here whats happening

[Greavesy]

yeah that sounds a really good idea i shall get a video after work tomorrow. and post it. How do you go about over fueling may i ask? and the carb has been on for a year. would this not matter as it can happen at any point?

[Mikey CB500]

It seems wierd to be honest. Other that that only thing i could think of is possibly due a rebuild.

Whats the milage?

Has he recently fitted any performance mods which may be causing problems? Ie it was fine before but hes changed someting and now its not working right

[Greavesy]

hey, thanks again for your reply, and nope nothing new has been fitted thats why its so confusing, its got 27k miles. the gear box hadnt been re oiled for the past 3 years. but we put new oil in, cleaned it up and checked it funnily enough everything look ok. Barings were still round and solid. but no performance parts have been put on recently. yet to check the carb for what you said about it bogging down.

[Greavesy]

but yeh i also think the thing is just about ready to die. and needs a rebuild.

[Mikey CB500]

Sounds like possibly the rings either gone or on there way out, is it low on compression? Struggles to start?

[Greavesy]

Ummm no its fine to startwith, as soon as it gets to 35 it bogs down again. Its really weird. what ring are we talking about?

[Mikey CB500]

Piston rings buddy

[Greavesy]

ill let him know to check them out, thanks bud. I've got a post on here about my CBR 125 RS5. Took it apart looks like front sprocket.

[st3v3]

The fact it get's to a certain speed ok says it's not rings.

How tight is the spark plug?
____________________
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[Mikey CB500]

But also he mentioned sometimes it struggles to pull off and will only go 200 yards and die

Sounds like rings or head/base gasket leaking really, or a damaged piston possibly?

[cb1rocket]

has it actually got 2 stroke oil in the tank and is it blue smoking? Also checked that the pump is working?

[Greavesy]

hi guys, spark plug was tight yes, replaced anyway just to be on safe side. No blue smoke, however with a 100cc carb the bike runs very rich, No oil is put into petrol tank. I don't know if he has checked the pump, i shall suggest it. The engine hasn't been looked over as far as i am aware as we didn't think it could be an engin problem. Sorry if reply is abit dodgey long day at work very tired shall get back to you guys first thing in morning after getting my new sprocket set for my own bike as its royaly shagged and got issues hopefully the sprockets will fix the problems however this matter is listed in another one of my posts. Thanks