I finally got my bike going so in my infinite wisdom I thought I would make it go a bit faster so I rejetted it and drilled some holes in the air filter, set the oil pump and powervalves
I then went to ride it and it chugged to a halt felt like it ran out of fuel

now when I start it the power valve motor sets then resets everytime
and when it does occasionally start it runs on one cylinder
coils are fine so are plugs it sparks when not in the cylinder and occasionally when I give it a slight rev
any Ideas?

Welcome to the site.

How fast were you going at the time?

How have you rejetted it, and what jets are you now using?

What other mods have you done?
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MC21SP Plaything
BMW F800GS Bumblebee
Triumph 9551 Daytona Big boys toy
FJ1100 Sporting relic
GTS1000 oddball

my mate had the same thing happen and it was a bad battery and charging system

well I put 132 main jets in but since it died I put everything back to standard I was flying along at around 30kph when it died it didn't sieze if thats what youre thinking just sort of chugged to a halt
it never accelerated properly up to this point either
When I put new plugs in it runs but spits out fuel then they foul
Im getting some new carbs and a pgm next week so Ill see if that does anything


battery is new

I was thinking of what wiring mods may have been done, and 132 sounds pretty small to me. What jets was it running before you changed them?

Did you drill holes in the filter, or in the airbox lid?
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MC21SP Plaything
BMW F800GS Bumblebee
Triumph 9551 Daytona Big boys toy
FJ1100 Sporting relic
GTS1000 oddball

Ive done the wire splice but it was running properly after I did this
128's are standard so 132's are a few sizes up
yeh I drilled a few holes at the back of the lid

the bike is actually a mc21 which had siezed so I put all the internals out of an mc18 into it Ive had it running properly before I decided to modify it
so im pretty sure its something I did to it

Sounds to me like you may have stuck float needles. spilling petrol out the overflow tubes ??????. sto be spiting fuel out the exhaust meens abucket load of fuel going in.


Tom
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"No Fear" Just Means You Aint Going Quick Enough Yet.
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that was my original thought but there is no petrol coming out the over flows
when needles are worn is it visibly noticeable and how much effect do the air screws have?

I doubt it's float needles then if it's not coming out the overflows.

Have you done a compression check?

Maybe you should return the bike to how it was by taping up the holes and dropping the jets to see if the fault is still there, that way you will at least have a starting point.
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MC21SP Plaything
BMW F800GS Bumblebee
Triumph 9551 Daytona Big boys toy
FJ1100 Sporting relic
GTS1000 oddball

compression is fine around 110psi pistons and rings are new

I was actually running open carb when I was testing but airbox seems to have no effect

I just got an MC18...

I have a similar problem...

I have a stock MC18
standard jets.
tyga pipes.
open airbox.
no-battery.
running 93 octane super unleaded...
and just some regular two-stroke oil...
standard plugs NGK BRE8 or what ever...forgot...

I kickstart it it starts fine...

I ride around town, it rides fine..

Accelerate with POWER holding the throtle cracked at 1/2 to
3/4 it hits the power band around 9k-10k.

cool...

but I get on the highway...
accelerate up to about 100kph-120kph
and hold it in 6th gear...for about a mile...
and one piston seems to go dead...

get off at the exit...and whil idling the piston starts firing again...
I think that it is the top piston....

is it fuel starvation?

I checked the carbs...took them out...check the floats, jets....
emaculately clean...

the bike was aquired by a collector before I had it...
sopposedly...the whole bike looks in really good shape...
I think he restored it.....

I held the tank up...turned the fuel cock and fuel just flowed out...
so I don't think it is the tank...

but tomorrow I will dain the tank an remove the petcock..

I will also install a battery...

someone said up there, that some guy had that same problem
and it was that he had no battery....

-cheers..

You definitely need a battery, as you're likely to killth eignition unit (PGM) without. The battery has a tendancy to take the rough edges off the generator output, as well as provding power to the circuits when starting. I'm impressed you started it at all!

It could be fuel starvation, have you checked that the feed hose from tank to carbs is in good condition? I have heard of them swelling and reducing fuel flow when old.

Otherwise, it may be something electric getting hot and breaking down, like the spark plug, cap or lead. Have a good look at the cap and the connection to the lead, as well as the coil and it's electrical connections to the loom.
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MC21SP Plaything
BMW F800GS Bumblebee
Triumph 9551 Daytona Big boys toy
FJ1100 Sporting relic
GTS1000 oddball

Hello, welcome and;

mister_robato wrote:I just got an MC18...

I have a similar problem...

no-battery
running 93 octane super unleaded...
and just some regular two-stroke oil...
standard plugs NGK BRE8 or what ever...forgot...

a battery may help, nomal fuel is fine, the best oil money can buy is essential and the correct plugs would be good, quote Honda "use of plugs other than BR9ECM/BR10ECM or equivalent may damage the engine."
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yes I have the correct sprakplugs...the br8ecm...
i wonder if I should get the cooler plug 9...
as it has been said that the rear piston gets hotter...


but after running the engine the plug looks great...
nice brown color...

I will get the battery today and check the fuel line again today...

i mean I have the 9's in both imean I could try the 10's

plus it is here in michgan...
and it is getting colder already...
so I was thinking that 8's and 9's would be ok...