Derbi Gpr sick [Archive] - Bay Area Two Stroke

PDA

View Full Version : Derbi Gpr sick


hudson084
09-04-2009, 03:43 AM
Hello im hudson this is my first post so bare with me



I have a 01 Derbi GPR 50 R when i got the bike the big ran fine but as soon as i started really useing her oil light came on and when it did the bike rev would slowly rise so i pulled the choke out a little and her rev went back down but now i cant rev past 8,000 Rpm when i use to rev to 13,000 her oil light constintly is on i did run out of oil so i replace the oil with some VAlvoline multi-purpose 2 cycle engine oil the oil light never went away and when i ride for like 10min the engine is VERY hot i really want my babe back so plz tell me whats going on i took the carb out yester day and cleaned it no diffrence PLZ HELP ME

Gunther1000
09-04-2009, 07:04 AM
Hummm, Is the pump primed? Is it actually putting out oil?

Does it smoke?

Ever thought of trying a little premix?

What main jet ya running?

Change anything like the pipe or air filter before or as this started?

Four_Ari
09-04-2009, 10:44 AM
Has anyone used that oil before? I always use Motul and never have any problems. Also do you think that your choke could be stuck on?

The reason your oil light is coming on when you gas it is because when you take off the oil moves away from the sensor. That just means its time to top off the 2 stroke oil.

keep us posted
-4ari

hudson084
09-05-2009, 09:38 PM
hey Guys im back okay the bike is still acting dumb i havent got new oil yet The pump actually does put out oil but the bike wont rev past 8,000 rpm Some one told me 2 go get the gap in my spark plug Check im gona dot that 2 day i use 50/anti/50 colant is that good in the radiator Also my dad a mechanic and he thinks the mixture is off cuzz oil comes out the pipe but i think thats from the choke being out when the chokes in the bike will just rev really high by it self and it does not go back down this shyt is crazy i was thinking of going pre mix but i know im not gona do it cuz im dumb but im gona go get new oil and get the spark plug conditioned if that dont work plz sugest otha options

Gunther1000
09-08-2009, 01:53 PM
It sounds to me like you my son, Have an air leak.

The boot around the carb is prone to not hold a tight seal.

Take it and the reed cage off and make 100% sure they are sealed up tight. I use a little RTV Hightemp silicone around both of mine to kill any air leak possibility.

Also check the top of the carb where the throttle cable goes into the carb. There is a rubber gasket up there that can also leak if not in right. They are very thin and could tear also.

If all this fails try spraying some wd-40 or carb cleaner around the carb and intake while it idles (assuming it will even with the choke on) and you should find a spot that makes it rev up once sprayed.

Air leak equals really lean. Don't ride it!

Gunther1000
09-08-2009, 01:56 PM
And are ya sure that light wasn't the temp light? Lean would mean HOT and = Melted piston...

Chances are (dare I say) that if you ran it like this trying to hit top speed or high rpm you fugged up the soft piston with a glowing ball of fire.

The rings are probably stuck in the piston grooves and the plug would more than likely look like it had a sparkler held to it.

It's pretty easy to get a look at the piston top by taking the pipe off or shit even the plug may allow a peek inside with a flashlight.

You will know right away if your lack of oil did any damage.

Cross your fingers!

And give us an update when your done!

hudson084
09-11-2009, 08:42 AM
I HAVE AN AIRLEAK MY FIREND DAD Took a look and said it's definitly an air leak to day im gona take the carb out and seal it up and im gona check the read cuz i bet thats were the air leak is THanks and is their any more places were i need to look for that air leak i so bet it's the carb or reed cuz i thought i saw it suck air as i was washing the bike when it was in idle ima take a look another thing if i take the card apart the gasket is only good for one seal so can i just use a platic sealer is this okay THANK PLZ REPLY back where to look for more air leaks

hudson084
09-12-2009, 10:09 AM
where do i look for theis air leak im bewildered every thing down by the reeds and carb looked fine with already good seals can u post pictures where to look im a newbie

Gunther1000
09-14-2009, 09:35 AM
It sounds to me like you my son, Have an air leak.

The boot around the carb is prone to not hold a tight seal.

Take it and the reed cage off and make 100% sure they are sealed up tight. I use a little RTV Hightemp silicone around both of mine to kill any air leak possibility.

Also check the top of the carb where the throttle cable goes into the carb. There is a rubber gasket up there that can also leak if not in right. They are very thin and could tear also.

If all this fails try spraying some wd-40 or carb cleaner around the carb and intake while it idles (assuming it will even with the choke on) and you should find a spot that makes it rev up once sprayed.

Air leak equals really lean. Don't ride it!



Other than what I have already told you, I'm as lost as you.

teenadvisory-
03-31-2010, 03:09 PM
unlike most seem to on here, i know what im talking about. i got a 2000, so same model, same engine. if u ran out of two stroke, its not the oil your uning thats causing you a problem. friction is causing your overheating due to lack of two stroke. u need to bleed your oil pump mate. simple as. there is a v v tiny screw above the throtte valve. open it alot until oil comes out. and thats it. u wil then get oil, and get lubrication and get less friction meaning less heat. although, by this stage you might have done some damage to pistons, rings, or worse... your cylinder.
as for your carb, leave!!!!!!! overly complicated unless you know precisely what every part is and its service capabilities.
apart from that, do urself a favour and leave malossi tuning kits well alone of you need new cylinders etc... there not worth the extra 150 ull pay. just get some half decent parts, run her in gently and then tune via the carb + reed valves. although if you get aftermarket reeds you may need to port polish your exhaust with a dremmel tool to get the best performance out of it. this keeps reliability as wel , just smoother gas flow out of the cylinder head.
need anymore info just email me :)

teenadvisory-
03-31-2010, 03:16 PM
where do i look for theis air leak im bewildered every thing down by the reeds and carb looked fine with already good seals can u post pictures where to look im a newbie
If an air leak occurs on a two stroke it'll most likely not run. simple as. trust me, as a motorcycle technician myself, its not your carb. if your carb has leaks itll create no back pressure to air pulling the next lot of fuel in and the main thing you'll find is the fuel will piss out all over the place. haha. and if your reeds are damaged, then itll not run either. reeds are a valve that stops the fuel mix being pushed back out into the carb when the piston moves down. because its the movemnt of the piston that forces fuel into the chamber in a two stroke. no valves what so ever. im rambling on tbh, read my post further sown or email me it u ever want to know anything else.

dankerson
04-01-2010, 10:30 AM
you need a leak tester. I had to make the ont for my bike. You can buy one for like 190 bucks.

ToraTora
04-19-2010, 03:05 AM
Has anyone used that oil before? I always use Motul and never have any problems.

I've used it, it meets all the specs for the bike, and you can find it at the auto parts store when the bike shops are closed. :P

I have seen the light come on when the tank has too much oil in it, though that doesn't sound like the issue here.

-Rob-