Honda Motorcycles - FireBlades.org banner

1 - 16 of 16 Posts

·
Registered
Joined
·
14 Posts
Discussion Starter #1
so heres the story, got the bike a few months ago...was pritty rough looking as it was exposed to the elements for a few years...first thing i did was clean it up and strip and clean the carbs...no luck starting so i sprayed carb cleaner directly into it while it was turning over and fired up stright away and then just dies...has new plugs and its all been cheaked with timing light. im starting to get really desperite because its turning into a dead end project. i have no clue where to go to next. any help would be much appriciated!!!!
 

·
Registered
Joined
·
5 Posts
hi mrwho69able

hi i have never owned a cbr250r before but i can give some troubleshoot ideas

firstly check the screw on the side of the float bowl undo it and see if fuel comes out.If no fuel comes out check tha fuel supply, start with fuel tap, then the pipes, then the fuel pump.

many thanks caspa1990
 

·
Premium Member
Joined
·
32,034 Posts
so heres the story, got the bike a few months ago...was pritty rough looking as it was exposed to the elements for a few years...first thing i did was clean it up and strip and clean the carbs...no luck starting so i sprayed carb cleaner directly into it while it was turning over and fired up stright away and then just dies...has new plugs and its all been cheaked with timing light. im starting to get really desperite because its turning into a dead end project. i have no clue where to go to next. any help would be much appriciated!!!!

My guess is you need to clean the carbs and fuel system.
Does it have a fuel pump and is it working?
 

·
Registered
Joined
·
14 Posts
Discussion Starter #4
yeah ive cheaked everything over....including air fuel mixture screws and such all cleaned properly....the only thing is the fuel pump, wasnt working when i got the bike but apparently works on gravity feed?? also all the bowls are filled with plenty of fuel and this is good seal on the vacume lines
 

·
Registered
Joined
·
14 Posts
Discussion Starter #6
yeah you can delete the fuel pump and let it run on gravity... my friend did it on his CBR 600 F3. But you have to bypass the pump to do it
yeah thats how it was orignal set up...someone before me hacked the wireng to the fuel pump so i got the fuel pump working agin but stright off the battery...did not make much difference. still just kept winding over.
 

·
Registered
Joined
·
14 Posts
Discussion Starter #7
hey heres the latest update ....new something wasnt right internally....striped it down and found 2 bent valves...anyone know where i can get 2 exaust valves and a head gastket for a mc19 honda
 

·
Premium Member
Joined
·
32,034 Posts

·
Registered
Joined
·
14 Posts
Discussion Starter #9
im pritty sure the head and pistons are different...the mc22 was the restricted port version therefor im assuming the valves are different
 

·
Premium Member
Joined
·
32,034 Posts
im pritty sure the head and pistons are different...the mc22 was the restricted port version therefor im assuming the valves are different

I would think most wreckers would have CBR250RR engine bits as they do tend to implode eventually.
Had a bit of search but I can't find online fiches for the MC19.
Have you tried a local dealer already?
 

·
Premium Member
Joined
·
32,034 Posts
yeah they said they dont have a parts list and cannot supply them cose its a japanese import

According to Wiki the engine was the only thing that didn't change between the MC14 and MC22.
Honda CBR250 - Wikipedia, the free encyclopedia

"The only feature that was adopted from the previous model CBR250s was the MC14E engine. This was slightly modified with a crankshaft that had 27.5 mm small-end journals, up 0.5 mm from the previous 27 mm journals. The engine also used a completely new set of VP carburetors that had smaller throats, reduced from 32 mm to 30.5 mm. These carburetors were fed by a vacuum operated pump for fuel delivery."

I don't know enough about the 250 engine to be able to say if they're the same or not.
You have the head off already?
Have you determined why the valves are bent on just one cylinder?
 

·
Premium Member
Joined
·
32,034 Posts
yes the head is off.......im assuming blown head gasket and water compressed or something in that nature

The head gasket was blown?
Water compression won't bend valves.
If the cam timing alters then you'll bend valves on all cylinders.
If you spin a rod bearing you can bend valves on just the one cylinder as the piston comes up higher due to the extra bearing clearance.
Hyraulically locking on coolant though is more likely to bend the rod, I can't think of any way for it to bend the valves.
The other option is debris entering the chamber, usually a piece of the carburetor or spark plug.
If you wind the engine past TDC so the crank is starting to pull the piston down the bore, stop and press on the piston. If the piston has any downward play then the rod bearing has failed.
 

·
Registered
Joined
·
14 Posts
Discussion Starter #15
ohhh yeah its probebly debris because there was mud wasps making there home near the intake ports...i might also add the pistons have sideways play but my brothers a mechanic and said it shouldnt lose compression if the rings are still good
 

·
Premium Member
Joined
·
32,034 Posts
ohhh yeah its probebly debris because there was mud wasps making there home near the intake ports...i might also add the pistons have sideways play but my brothers a mechanic and said it shouldnt lose compression if the rings are still good

While the carbs were off?
Be sure to check for play in the crank though as it's usually the rod bearings that fail.
Very high rpm requires very religious oil changes which is the downside to these as learner's bikes.
It's probably also worth confirming it does still have the original MC19 engine in it.
 
1 - 16 of 16 Posts
Top