SPARTAN Zylinderkopfmontage

i haven't seen anyone compare this head to the stock OEM XR100/CRF100 head, the first thing you notices about the Shift Up head is the bigger valves about 25% bigger and smaller valve stem's along with the smaller/lighter valve springs which allows it to rev faster/higher, the intake and ex ports are also a big upgrade, the intake port seems to be the same size as the stock head but it doesn't taper like the stock head which seems to allow more air flow with less restriction, as for the exhaust port the Shift Up head actually has a much smaller port i would say 15% smaller, it does have more of a straight/ more open port, it doesn't taper like the stock head exhaust port does but like i said the Shift Up is a smaller exhaust port, but with that being said there is a lot of material that you could easily open up that port and port match it with your exhaust. PLEASE SEE PICTURES BLOW

Machine work seems good with the exception of the oil check/cooler port that wasn't tapped for threads. This hemi head will drop compression if not paired with a domed piston but the bigger, light weight valves sure help it rev much quicker.

This cylinder head will give you bike a boost of power with larger ports and larger valves. It also has heavy duty valves springs and comes fully assembled and ready to install.

This cylinder head will add horse power to your motorcycle. This can be used with pistons that have a higher dome than the stock piston.

Hello, I am interested in this cylinder head BUT there are no specifications at all that would convince me to buy this head over the stock replacement. I read the claims this head FLOWS MORE than stock but no numbers. How much more airflow than stock and where in the valve lift was the flow improvement? Hopefully not outside the usable RPM range.I read this head has huge valves over stock but what are the sizes? Huge valves on a small 80cc or 100cc engine won't guarantee a big power gain. Example, your stock head is worn out, both valves are leaking so major loss of power. Install this head ( or any head that is fresh ) and now big power gain. Was it really the head or just a fresh valve job? This is the big mystery here.I would like to know if it was this head itself that made the major improvement. I think anyone looking for this head already NEEDS IT because their head is worn out otherwise they won't be here they will be out riding their bike. It would seem most likely what the person felt was the recovery of power your engine lost over time as it was wearing out. Now you install a new fresh part ( this head ) and now everything seals properly so what a power increase this new part made when in fact the engine could now be making less power than when it was new but more than it had prior to the head swap. Since an 80cc or 100cc stock bike makes about 5.5HP ~ 6HP. If your engine was down to 3.3HP because of a worn out head and now it jumps back up to 5.5 or 6HP that feels like a big power gain. So with that said a fresh valve job and cleaning the carbon out of the ports may have given very similar results. We do not know for sure. What people need to know : 1.) What are the intake and exhaust valve sizes on this head?2.) What is the ACTUAL CFM FLOW improvement and at what camshaft lift? Or at least give the port volume in CC's compared to a stock head.3.) What is the compression ratio on this head or at least CC's of combustion chamber compared to the stock head? Is it the same or higher? ( Hopefully not lower )4.) What are the major improvements to this head over the stock OEM Honda head that will convince me to buy this one?Until these very basic AND ESSENTIAL questions are answered I would have a hard time convincing myself to buy this head over the stock honda part. The stock head is about the same cost bare here in the USA direct from Honda.