Hi all,
I'm having some problems with my 1993 cbr250r/rr a the moment. Appreciate any help that can be given.

So, my motor sounds like a tractor!!
I've been building this bike for a while and the only thing stopping me from putting it on the road is this problem.
What I've done so far-
-Cleaned the carbs out - even tried another set i knew worked
-Replaced plugs (have checked plug clearance) and leads
-Tested with coils which I knew were fine (from another bike)
-Changed the bridge rectifier
-Checked the connections on new headup display
-Compared the leads to a working bike (1990 model) to confirm they're on the right plugs

I'm definately getting spark from all plugs as I have checked.
I know it's running on three cylinders as one of the exhaust pipes aren't heating up. ( I'm pretty sure it's cylinder 3 - 3rd from the left) I've used some easy start sprayed directly into the carbs but still no joy.

I'm thinking that I may have a ceased valve in that cylinder or a blown head gasket.

Not sure what to do now apart from taking to a mechanic which I am trying to avoid at all cost.

Thanks for any help

Bit of history on the fun I've had so far.....
https://cbrforum.com/forum/new-membe...9/#post1047127

 

i say pull that plug out and take a gander at it see if its wet or anything . .and whilst you have it out might as well check the compression . . .if you have a bore scope or can get a hold of one stick it down in the spark plug hole and take a gander in tyhere and see if you see the valve if you see the valve more than likely it is bent . . .if the valve has stuck before while running the piston has come up and smacked it causing it to bend and now the cam rockers have fallen out and are sitting in the head. that will casue no compression and obviously a misfire, and weith a bent valve i know exactly what yuou are talking sabout it sounding like a tractor . .its a hooooooooooooorible sound . .sounds like a loud diesel truck . . .let us know

 

Hi Turbo,
Thanks for the reply. This was my worry. But all signs are pointing that way. I'll see if I can get a hold of a borescope and see whats happens. In your experience what's the fix if this is the case?Eg, parts etc.

Might have to put on hold for a month to save some more $$

We'll see what happens
Cheers
Mitchonda

 

Hey Mitch, don't take this the wrong way mate, but you are chasing the wrong mob here. The MC19 and MC22 were never imported to the US. You want to be asking these questions to experts on those bikes. It just so happens I used to live in Melbourne and owned an MC19 so I will help you out here.

Go to this forum:

Honda JDM CBRs Forum

Ask them your questions... someone will be more than glad to help you. If you are in a capitol city I am certain you'll even get an offer from someone to come give you a hand working it out. Just feed him a few cans and he'll be right...

Good luck! They can be touchy bikes, but they are bloody good fun! I miss mine very much!

 

id say pull the head off yourself and get a whole new valve kit for it springs valves seals the whole nine yards . .take it to a local machine shop and have them mill it and put the new valves in . . i work on cars and i took my honda ATC head to my guy and he laughed and did that for free im sure it would cost pennies doing it that way compared to having someone do all the work only if thats the case though

 

It's just possible that the carb feeding the defective cylinder isn't getting enough fuel. Could be the float height is wrong or maybe a blocked pilot jet. Turn the fuel on for about 10-15 seconds and then off again and then drop the float chamber on the defective carb to see if there is enough fuel in the float bowl. Double check the idle mixture screw to make sure the initial setting is correct. Slowly screw the screw in and then out around 1 and 1/2 to 2 turns and see if that helps.