How do i get my motor to rev right out??????

[matesrates]

Hi there
I have a 66 slant head skyhawk.. with a ("speed carby") (Red air filter cover)
With a bpr6hix (gaped 0.25) and thick copper core spark plug wire
Long street exhaust...
My problem is i can't get the engine to rev right out...
It runs good but ,,,it's not peking right out?????
I have tried to ajust the c clip settings ....
Engine is only around 100 km old
So does it just need to be broken in????


Please any comments more than welcome

Thanks in advance

 

[Bikeguy Joe]

Break in will help, and those long pipes take a bit off the top end.

 

[matesrates]

Break in will help, and those long pipes take a bit off the top end.

Hey joe
Thanks for your reply
When i 1st fitted this engine it did rev right out.....But stock plug made it miss fire and run like crap..

Do you suggest modifing the exhaust???
Also when i turn the engine off it does a backfire???
Where the big nut connects to muffler.....It seems to be loose but i can't tighten it up anymore???
Have you heard of this problem????
How do i enclose this nice and tight???
These have no baffle right??? As whole exhaust is welded shut...except for the big nut that connects the muffler....
What could i do??
Thanks for your help

 

[matesrates]

Break in will help, and those long pipes take a bit off the top end.

Hey there
when stopping my engine it does a backfire
Is this caused by the muffler being loose????????????
How do i modify it so i can tighten it up???
At the big nut i can not tighten it up anymore..
Thanks for your help

 

[Bikeguy Joe]

Without the pipe in front of me, I can't answer those questions, but yes, I would suspect that the loose fitting is letting air in and that can cause a lean condition.

 

[killercanuck]

Is this caused by the muffler being loose????????????
How do i modify it so i can tighten it up???
At the big nut i can not tighten it up anymore..

Hiya, yea its hard to tell without pics... Is the pipe held on by acorn nuts? if so, try going to normal nut or double nuts(to lock'em), or file down the end of the stud to get an extra turn out of the acorn.

Or, maybe add another gasket?


edit- oh yea, check your carb-to-intake manifold is sealed properly and isn't leaking air too. my bike wouldn't rev past 3/4 until I fixed a bad seal from the carb to the intake manifold. (is currently plumber tape till i can use dad's vice)

 

[jauguston]

Needle clip in the top groove. See if you can find a couple of leaner main jets to try. The Scootershop.com has jets. Stock is a 70. Try a 68-66-64. They were out of 66 the other day. I put a 68 in mine and it is better and will try a 66 when he gets some more. They are 5mm Delorto jets.

Find a 1/16" stock diameter o-ring that will fit into your carb where it goes onto the manifold and goes back against the shoulder that is there. Push the carb into the o-ring while tightening the clamp. That will seal any air leaks there.

Is your plug black? Most likely it is----too rich.

Jim

 

[matesrates]

Hiya, yea its hard to tell without pics... Is the pipe held on by acorn nuts? if so, try going to normal nut or double nuts(to lock'em), or file down the end of the stud to get an extra turn out of the acorn.

Or, maybe add another gasket?


edit- oh yea, check your carb-to-intake manifold is sealed properly and isn't leaking air too. my bike wouldn't rev past 3/4 until I fixed a bad seal from the carb to the intake manifold. (is currently plumber tape till i can use dad's vice)

Thanks for the reply
Thanks i will try to seal the carby up to manifold...
Sorry but i don't know how to post pics up but
The Big nut that is loose..It is not on the engine...It is a long street exhaust..Or other name is poo poo pipe..
Where the end muffler connects to the pipe there is one big nut to connect it...This is loose and i can't tighten it up
Can you think of anything to seal this????

Thanks for your help

 

[killercanuck]

ohh, maybe take the nut off and add a couple of washers? That'll give you another few mm for it to bite down on.

np, gl.

 

[jauguston]

If you take the nut off and separate the two parts look at how the connection works you should be able to figure out a solution. Its not rocket science.

Jim