Compression in question

GoldenMotor.com

langolier

Member
Jul 6, 2015
57
0
6
Wisconsin
Bike is running good (as far as break in goes) have a 2cyc 66cc with RT carb #65 jet, A 24:1 mixture (for break in) and a banana pipe @750 asl. With That being said I put a DAX high compression head on and it fires once then nothing. Put back on the stock head and runs fine..... My theory.... Running a 24:1 mix with a high compression head does not have a high enough octane to run correctly ?
 

Davezilla

New Member
Mar 15, 2014
2,705
10
0
San Antonio Texas
Check your spark plug gap... more compression makes it a little harder for those electrons to jump from point A to point B... try closing the gap to .024" and see how that does...

Another thing to consider is gasket sealing... make sure the gasket surface on the head and cylinder deck are both flat and true... sometimes a little lapping is needed to match everything up, and a tiny leak at the head gasket area is a big problem.
 

langolier

Member
Jul 6, 2015
57
0
6
Wisconsin
Good points Dave. I'm using a Iridium 3prong plug now but have a B7HS NGK I can try. I did lap the head but not the jug, wouldn't hurt to do that. Will try tomorrow. I was debating if I should wait to put the head on till I had more break in time on the motor but I guess I'm a little anxious to try. Thanks.
 

langolier

Member
Jul 6, 2015
57
0
6
Wisconsin
Problemo found, When working with China Murphy's law will be prevalent. Actually it was my oversight, Cap nuts (blind taped) are used to bolt the Dax head because of bolt/socket clearances in the head. Found out head studs were bottoming out just enough to not getting proper torque. Added some washers and engine fired right up. soooo.... All in all I updated:

1) From CNS to the RT carb w/#65 Jet: Big improvement on starting/idling and some amount of performance.

2) "Bannana pipe" which added a bit improvement and a bit louder.

3) A Dax high compression head which gave a big improvement on lower end torque.








dance1

(Do I need to downsize these pics ? or is this acceptable ?)
 

langolier

Member
Jul 6, 2015
57
0
6
Wisconsin
Well I figured out what the problem was, When working with China Murphys law is always prevalent. Actually it was an oversight on my part. The Dax Head has a deep socket for the bolts so I purchased some deep socket cap nuts (with blind taps) for mounting. They tightened the head down but were bottoming out the studs before I could get the need torque. So just adding some extra washers worked, Fired right up. Soooo Here is my take on my add-ons :

RT Carb (replaced CNS) : starts and idles much better. Also enhanced performance some. Ill give it a score of 8.

Banana exhaust pipe: Enhanced performance a little and is a little louder. Give it a 6

Dax High Compression Head: Noticeable torque increase in low and mid RPM’s and head runs much cooler. Give it a 10 (very good bang for the buck)

I’m sure there are other mods out there that work as well or better (or worse) but I just wanted to give my impression on what I have added.

some pics







dance1


(Re these pics ok or do I deed to downsize ?)
 

Davezilla

New Member
Mar 15, 2014
2,705
10
0
San Antonio Texas
Glad you got it fixed... Yeah, those acorn nuts don't do anybody any favors and many of us just get new regular nuts from a hardware store because of just that problem.

BTW... Very nice Bike!!