66cc won't fire?

GoldenMotor.com

Apollo 66

New Member
Aug 26, 2012
18
0
0
Australia
Hi

Had my 66cc for a couple of months now. Have since replaced the the standard pipe with SBP tuned pipe and the standard carburetor with an RT Dellorto knock off.

I have also replaced the spark plug with NGK bh6s and the lead and boot.

The bike has been getting progressively more difficult to peddle start and doesn't even fire with 'quick start' sprayed down the cylinder anymore. Last time I had it running, two days ago, I sprayed 'quick start' around the inlet manifold to look for vacuum leaks. I also sprayed on the joint of the crank case directly below the carburetor and engine revs went down with each spray. Waiting for the gear removal tool to be delivered so I can tear it down for a look.

Has anyone else come across a leak in this location? And, would this issue prevent the engine from firing? I have good spark.

Any feedback would be greatly appreciated.
 

Joel G.

New Member
May 2, 2012
16
0
0
Guam
First, you might want to just go ahead and put the old carb on.. which you probably have by now? Is it acting the same? Secondly after getting it started and running down the road, what is the performance like? On my 66cc I checked the bottom gasket for cylinder head and well on mine it was somewhat cock-eyed and not allowing proper air flow.. maybe with the upgrades you have purchased the minor issues (gasket leaks?) might inherently becoming more noticeable? Anyway, let me know what you did. Later -Joel
 

Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
11,837
252
63
up north now
A case gasket leak while not as common as the intake leak, will cause that problem.

You can try a temporary fix by smearing some RTV (silicone) in the are where you found the leak. It helps if you work it into the joint like you would grease a wheel bearing.
 

Apollo 66

New Member
Aug 26, 2012
18
0
0
Australia
Thanks guys

Will install the original carby. I had applied rtv along the joint but didn't smear it in. Will give it a go. I'm worried that the crank case bolts may be vibrating lose internally.
 

Huffydavidson

STREETRACER/MANUFACTURER
Jan 29, 2012
1,076
4
38
st.louis,mo.
Go to norms repair and take a class. You're in the right school just find your class . The answer to your problem grasshopper is here but you must find it yourself .use this forum to its full potential . you are the students you have the power within your grasshopper .
 

Al.Fisherman

New Member
Sep 9, 2009
1,966
5
0
Calera, Alabama
I have seen the case gasket leak. The crankcase leaks between the crankcase and clutch section. This is not a common problem. If this is the case, you can't find the leak without splitting the case.
 

darkhawk22

New Member
Aug 17, 2010
733
8
0
Acworth, GA
A bad CDI can cause your problem, they burn out fairly easily. Remove the plug and with it connected to the spark plug wire hold the plug close to the motor and pedal and see if you have a spark. If there is a spark then it's good to go and there is an issue somewhere else. The other issue could be a restriction in air flow in the exhaust.

I literally just had this same problem and did the following:
Replaced plug with a new one. No luck
Replaced CDI. No luck
Cleaned air filter and checked carb. No luck
Took off banana pipe exhaust and flushed with straight gasoline and reattached. The bike started on the second pedal.
 

Apollo 66

New Member
Aug 26, 2012
18
0
0
Australia
Hi again all

Resealed the the cylinder assembly to the the crankcase and sealed the crankcase from the outside. I also removed all the fuel from the crankcase (lots there). Fired up first go and has been running very well since.

Thanks for all your wonderful comments.

Does any one know if i can purchase the high performance 'Jaguar' CDI in Australia? Shipping from JNMotors (the US) is very expensive.
 

Huffydavidson

STREETRACER/MANUFACTURER
Jan 29, 2012
1,076
4
38
st.louis,mo.
No it can not be purchased from anyone any where else yet. Yesterday he had 15 in stock. If you want one you better move fast he seems to only stock every 5or6 weeks. But there is away make your own.
 

Apollo 66

New Member
Aug 26, 2012
18
0
0
Australia
Ok guys. I'm at a complete loss. Lots of healthy spark. Sprayed plenty of quick start down the head via spark plug chamber. Does not fire at all.

Any help would be greatly appreciated.

Still running the SBP exhaust chamber and the delorto type carb.

Many thanks
 

Al.Fisherman

New Member
Sep 9, 2009
1,966
5
0
Calera, Alabama
Ok guys. I'm at a complete loss. Lots of healthy spark. Sprayed plenty of quick start down the head via spark plug chamber. Does not fire at all.

Any help would be greatly appreciated.

Still running the SBP exhaust chamber and the delorto type carb.

Many thanks
Check out the links in my signature. I wrote up a paper that will cover your problem. I have never run across a problem that wasn't covered there.
 

Apollo 66

New Member
Aug 26, 2012
18
0
0
Australia
Hi

It seems that the SBP Expansion Chamber somehow causes my engine to flood quite easily.

Does this make sense to anyone?

Many thanks
 

Al.Fisherman

New Member
Sep 9, 2009
1,966
5
0
Calera, Alabama
Last edited:

Apollo 66

New Member
Aug 26, 2012
18
0
0
Australia
Thanks guys

Al, I have performed all the electrical meter tests including re soldering all connections. It then fired up and I rode it for about ten minutes. Let it sit for half an hour and it wouldn't start again. Even with starting fluid sprayed down the spark plug chamber. I will install the stock exhaust and report back.

Johnny, I have half a dozen jets and tried a couple of them. Performed spark plug chop and all seems good. I reinstalled the stock carby and it still didn't fire. Rode it around for a while with the plug off , choke off and throttle open to clear any gas. Still nothing.

Will persevere.
 

Al.Fisherman

New Member
Sep 9, 2009
1,966
5
0
Calera, Alabama
Thanks guys

Al, I have performed all the electrical meter tests including re soldering all connections. It then fired up and I rode it for about ten minutes. Let it sit for half an hour and it wouldn't start again. Even with starting fluid sprayed down the spark plug chamber. I will install the stock exhaust and report back.

Johnny, I have half a dozen jets and tried a couple of them. Performed spark plug chop and all seems good. I reinstalled the stock carby and it still didn't fire. Rode it around for a while with the plug off , choke off and throttle open to clear any gas. Still nothing.

Will persevere.
If it won't fire, I suspect a electrical problem, low compression will also cause the engine not to start. But if the plug wire won't fire, then it is electrical. I have seen coils act that way.
 

Apollo 66

New Member
Aug 26, 2012
18
0
0
Australia
Thanks JohnnyR, yep, carburetor issue. Installed the stock carb and fired without effort. Will try smaller jets in due course.

Greatly appreciate your assistance.

Regards