5hp head on 6hp intek block

[pj_elia]

I got used replacement head for a 190cc 6hp intek. The head is from a 5hp intek. I see that it calsl for shorter head bolts and the intake diameter is smaller. Would this head work with the 6hp's push rods? Also what impact will this have on performance? The carb would be off the 6hp.

 

[minidragbike]

Not sure, haven't ran this setup myself.
But you can always grind the push rods shorter if needed. Or you can put a washer under the rocker studs.

 

[pj_elia]

well the head fit and runs well but It seems like it might not rev up as quick but might have some more low end power. I'll try to get a gps reading on the top speed that's my only baseline. The 6hp head (rom a 190cc) on the intake side was fully round and open. The 5hp head (from a 206cc) has a ramp that reduces the volume considerably. It seems logical that the 190 6hp head on the 206 block would be the best combo with stock parts. Anyway, I'll let you know if the top speed is different.

 

[pj_elia]

The bike is 2 mph slower. The motor is governed the same as before. The replacement head has the ramp inside the intake port while the original head for the the 6hp 190 was round all the way through. It looks like this is what made the 190 block a 6hp and the larger 206 block a 5.5hp. I ground down the ramp as best I could. Its much more open now. We'll see.

 

[pj_elia]

Its 2 MPH faster with the ramp ground down. Everything else the same. Its .4 MPH faster with a homemade header versus the stock muffler.