Hammerhead twister 90psi compression

tko248 · **Joined:** Thu May 14, 2020 3:37 pm **Posts:** 16

Hello all, thanks for any help I may receive.

I have a hammerhead twister 150cc that wouldnt start, I checked the compression and found it to be at about 80, dropped some oil in the plug hole and it went up to 120, which pointed to the piston rings. I then order a whole new set of rings, piston, gasket and housing. Replaced everything, adjusted the valves to 004 intake and 005 exhaust. now My compression reads at 90psi at WOT. any help would be greatly appreciated.

Once again Thanks

PGH · **Posted:** Thu May 14, 2020 5:28 pm

Did you set cam timing correctly?
Did you adjust the cam chain tension?
Did you gap the rings to the piston?
Did you offset the gaps when installing the rings?

tko248 · **Joined:** Thu May 14, 2020 3:37 pm **Posts:** 16

cam is good
adjusted the tension
rings are gapped and offset

tko248 · **Joined:** Thu May 14, 2020 3:37 pm **Posts:** 16

redid the whole thing with second piston and ring set and now up to about 95psi. it tries to start and i notice smoke coming out in between the cylinder and valve housing. new gasket there so i am still pretty lost. another thing i noticed is that I added about an ounce of oil in the spark plug socket and compression went up to 130psi again.

Funnyman · **Posted:** Fri May 15, 2020 10:16 am

Did you hone the cylinder so the rings could seat?

Funnyman · **Posted:** Fri May 15, 2020 10:20 am

Also ,I dont use synthetic oil for the break in.

tko248 · **Joined:** Thu May 14, 2020 3:37 pm **Posts:** 16

No I didnt, The cylinder is new and came with the piston, didnt think i needed to on a new cylinder/piston kit.

Funnyman · **Posted:** Fri May 15, 2020 11:36 am

No you shouldn't. Torqued to spec? Do have acorn style head nuts? Sometimes they bottom out. Cracked head

Funnyman · **Posted:** Fri May 15, 2020 11:37 am

Upside down rings

tko248 · **Joined:** Thu May 14, 2020 3:37 pm **Posts:** 16

what do you mean upside down rings? i have the dark one in the middle and the lighter one on top.

tko248 · **Joined:** Thu May 14, 2020 3:37 pm **Posts:** 16

No acorn style head nuts, tried 2 different heads same problem.

Funnyman · **Posted:** Fri May 15, 2020 12:09 pm

On the rings they dots or numbers , they are facing up?

tko248 · **Joined:** Thu May 14, 2020 3:37 pm **Posts:** 16

damn didnt check that, guess its time to reopen her up

tko248 · **Joined:** Thu May 14, 2020 3:37 pm **Posts:** 16

should they be facing up?

tko248 · **Joined:** Thu May 14, 2020 3:37 pm **Posts:** 16

update: fixed one ring (the top one) which was facing down and now im up to about 110psi, but still wont start. it tries and backfires like crazy but wont completely turn over.

Funnyman · **Posted:** Fri May 15, 2020 3:19 pm

Does the slide in carb move freely up and down?

tko248 · **Joined:** Thu May 14, 2020 3:37 pm **Posts:** 16

yes, brand new carb, i got 3 of them here

Funnyman · **Posted:** Fri May 15, 2020 4:10 pm

You might be a tooth off on your cam. Or maybe a sheared key on your fly wheel

tko248 · **Joined:** Thu May 14, 2020 3:37 pm **Posts:** 16

update: replaced the new cdi and spark with old one and it turned right on. thanks for your help funnyman and PGH, much appreciated.

Funnyman · **Posted:** Sat May 16, 2020 10:58 am

Glad you got it started but you should still have higher compression

Hammerhead twister 90psi compression

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