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DanGPR
07-04-2008, 05:52 PM
:bangwall:

Hey, basically, i have replaced the top end on my bike. And put the standard carb back on it.

But it won't run right, it will rev fine from idle, but when riding it, it is VERY reluctant to gain speed and rev out, also after about 1 mile of riding the engine will cut out and the bike will die

Cannot for the life of me figure it out, it is pissing me off so much as i am in the process of selling the bike!

Any ideas boys? I am desperate!

I am checking the compression tomorrow.

RS01
07-04-2008, 06:56 PM
What size carb did you have on it? did you change the reed block at all?
I know it wont be a biggy but you did rejet the std carb?

DanGPR
07-05-2008, 02:32 AM
I didn't change the reed block, but it does have carbon reeds in it, compared to the stock ones it had before.

It has the standard 14mm carb on it. It had a 21mm on it before.

And i have tried playing with the jetting, with no improvement.

bourney2007
07-05-2008, 09:15 AM
lack of 2-stroke getting into the cylinder?
Try running a tank of pre-mix.

When the engine cuts out is it hot?

Could even be that there is coolant getting into the cylinder. Check your head gasket.

williamr
07-05-2008, 11:01 AM
Carbon reeds are too stiff for this setup, but I don't think they're the main cause of your problem.

Have you done a proper chop to check the mixture. 'Playing with the jettings' isn't a phrase to inspire confidence.

Cutting out after a mile sounds like fuel starvation. Check the float, float valve, petrol tap, fuel pipe, tank vent.....

Could be a restricted air intake path - filter, choke not lifting off, rag left in the intake....

Rob

rs50 '03 steve
07-05-2008, 11:07 AM
do you mean by replaced the top end putting a nother 50cc on or was it a bigger bore.

DanGPR
07-05-2008, 11:40 PM
I went back to a 50 from a 70

I have an air leak from somewhere a long the intake tract, i think, could this cause it?

I will change the carbon reeds back out for the stock ones.

I don't think it is fuelling, due to it not spluttering or anything when it does cut out, it just dies like the compression has gone.

Which i tested yesterday, and is 90psi.

mx50boy
07-07-2008, 11:38 AM
try another spark plug

i had the same problem with my YZ85, it kept cutting out so i tryed a new plug and its going as right as rain now

dont think it will be the float sticking as they only run for 30 seconds or so on a carb full

bourney2007
07-07-2008, 02:51 PM
I went back to a 50 from a 70

I have an air leak from somewhere a long the intake tract, i think, could this cause it?

I will change the carbon reeds back out for the stock ones.

I don't think it is fuelling, due to it not spluttering or anything when it does cut out, it just dies like the compression has gone.

Which i tested yesterday, and is 90psi.


i suppose an air leak is possible.

Get a little bit of petrol on a paint brush and brush the petrol along the intake tract. If the revs change then you've found your air leak.

DanGPR
07-07-2008, 04:19 PM
Have changed the reeds back.
Have chnaged the spark plug.
Have checked the choke is not sticking.
Have checked for a leak.
It's got compression.
The jetting is PERFECT.

Apparently, a dirty carb or air filter could cause it, so going to clean them both through THOROUGHLY and try it again.

If that doesn't work, a blowjob to anyone who can give me a solution! :rolleyes:

bourney2007
07-07-2008, 04:24 PM
Have changed the reeds back.
Have chnaged the spark plug.
Have checked the choke is not sticking.
Have checked for a leak.
It's got compression.
The jetting is PERFECT.

Apparently, a dirty carb or air filter could cause it, so going to clean them both through THOROUGHLY and try it again.

If that doesn't work, a blowjob to anyone who can give me a solution! :rolleyes:


Im getting stuck for suggestions now lol. If all that dosnt work then maybe check your exhaust isnt choked up, a bit of a long shot i know but thought id suggest it anyway lol

mx50boy
07-07-2008, 04:27 PM
Im getting stuck for suggestions now lol. If all that dosnt work then maybe check your exhaust isnt choked up, a bit of a long shot i know but thought id suggest it anyway lol

hes defo after a blowjob now lol

:kidding:

bourney2007
07-07-2008, 04:34 PM
hes defo after a blowjob now lol

:kidding:


Yeah, obviously.
Im off to research everything there is to know about gpr50's to find the answer to dans problem, before anyone else beats me to it. Dnt pretend you arnt racking your brains aswel mx50boy, trying to steal my blowjob are ya? Lol

mx50boy
07-07-2008, 04:42 PM
Yeah, obviously.
Im off to research everything there is to know about gpr50's to find the answer to dans problem, before anyone else beats me to it. Dnt pretend you arnt racking your brains aswel mx50boy, trying to steal my blowjob are ya? Lol

ssshhh


hahaha
your hell of a fella


lol

DanGPR
07-07-2008, 04:46 PM
haha, i'm sure i can manage both. at the same time.

don't pretend you've never seen the movies boys.

bourney2007
07-07-2008, 04:51 PM
haha, i'm sure i can manage both. at the same time.

don't pretend you've never seen the movies boys.

Oh ive seen the movies alright,been there got the t-shirt etc lol.
Im not sure you'd be able to handle my beast alone, let alone with mx50boys thrown in aswell lol :kidding:

Cheers mx50boy, you a sound guy yourself mate.

luigi1991
07-07-2008, 04:54 PM
seems weve found the sausage fest here!

bourney2007
07-07-2008, 04:58 PM
seems weve found the sausage fest here!

You forgot to put a big smiley face at the end of that message didnt you mate. Lol :kidding:

luigi1991
07-07-2008, 05:25 PM
nah dont need a man my life thanks mate,
the girlfriend likes sausage like u wouldnt believe!

DanGPR
07-08-2008, 05:23 AM
Back on topic...

I have taken the air filter and all 3 jets out of the carb to give it all a good clean.

I was told this is pretty much all it could be...

bourney2007
07-08-2008, 04:38 PM
Back on topic...

I have taken the air filter and all 3 jets out of the carb to give it all a good clean.

I was told this is pretty much all it could be...



Fingers crossed then mate. Let us know how it goes.

DanGPR
07-10-2008, 05:12 AM
Cleaned the carb out with compressed air
Cleaned the air filter

I slight improvement, i think, but it is still not right.

I'm thinking that the ports on my cheap ebay top end have not been designed correctly and so the exhaust gasses are not flowing out of them consistently :confused:

rs50 '03 steve
07-10-2008, 05:14 AM
ok just read all the posts so ignore me

rs50 '03 steve
07-10-2008, 05:19 AM
check all your fuel lines starting from your tank to see if there blocked up or leaking, try and find some proper carb cleaner.
what make is the top end you got from the internet

DanGPR
07-10-2008, 05:36 AM
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&rd=1&item=160134444964&ssPageName=STRK:MEWN:IT&ih=006

If the fuel wasnt flowing properly, that would make the plug read lean , no?

rs50 '03 steve
07-10-2008, 06:02 AM
im not sure but worth a check anyway

bourney2007
07-10-2008, 04:50 PM
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&rd=1&item=160134444964&ssPageName=STRK:MEWN:IT&ih=006

If the fuel wasnt flowing properly, that would make the plug read lean , no?


Correct.

Just wondering as no one, including you, has mentioned it yet.
I noticed you had a bbk before this new 50cc top end. Well have you geared it down for the 50cc cylinder?

rs50 '03 steve
07-11-2008, 03:27 PM
that wont make it cut out though, did you turn the oil pump up on your big bore kit or did you leave it as it was, because if you turned it up it could be reading different to what it needs to be, make sure that you turned everything back to the standard set up.

bourney2007
07-11-2008, 03:29 PM
that wont make it cut out though, did you turn the oil pump up on your big bore kit or did you leave it as it was, because if you turned it up it could be reading different to what it needs to be, make sure that you turned everything back to the standard set up.


no but it could explain the not picking up the revs and taking forever to get up to speed.

I wonder if it is soft seizing?

rs50 '03 steve
07-11-2008, 03:34 PM
what does the temperature guages do when it cuts out?
is there enough coolant in it
have you tried fresh fuel
air/petrol/oil mixtures ok
correct jets and needle settings
what 2 stroke you using


get back to me:bump:

Rs50_2007kris
07-11-2008, 03:36 PM
New bikes don't have a temp guage

rs50 '03 steve
07-11-2008, 04:36 PM
what a rubbish idea, no wonder so many are seizing, not to mension the problem of people not running them in. (say that in a stan smith voice :D (i like american dad:spam:)

DanGPR
07-11-2008, 05:25 PM
what does the temperature guages do when it cuts out?
is there enough coolant in it
have you tried fresh fuel
air/petrol/oil mixtures ok
correct jets and needle settings
what 2 stroke you using


get back to me:bump:

1. No temp gauge. Just a light, but that doesn't come on.
2.There is plenty of coolant.
3. No i havent tried new fuel
4. Mixture is sweet as.
Its just cheap [fully synth] 2 stroke from my local garage.


It doesn't cut out anymore, and i have put the standard exhaust back on it, which seems to have relieved the problem of the revving slightly, but it is nt perfect.