If you wish to avoid sourcing a machine shop for porting and for the installation of new valve seats and oversized valves, ProCycle provides big valve heads that come with the oversized valves and seats pre-installed. To maintain this program, we require the return of your existing cylinder head as a 'core', which will enable us to install oversized valves in future cylinder heads. The installations are performed in batches, and all valves and seats are fitted into cylinder heads that have undergone professional cleaning, refurbishment, and porting to restore them to a condition that is comparable to new.
The installation of valves and seats in one of our cylinder heads, including the necessary porting machine work, incurs a labor installation fee of $520, which is factored into the kit price.
The core exchange process may be conducted in one of two ways:
1. You may send your existing stock/current cylinder head to us before we dispatch the big valve head kit. Upon receiving your stock/current cylinder head core in satisfactory* condition, we will promptly ship the big valve head kit directly to you.
2. Alternatively, we can ship the big valve head kit to you prior to receiving your core; however, this option requires a core charge of $1200, which is also included in the kit price. This core charge will be refunded to your purchasing card once we receive your stock/current cylinder head core in satisfactory* condition. You may also opt to receive the core charge refund as ProCycle Store Credit. Should you choose the store credit option, a $1,250 digital gift certificate will be issued, providing an additional $50 for purchases from ProCycle.
*Requirements for a good condition cylinder head core:
The head you send to us must not have any physical damage. It must have the original cam cover (Cam covers and heads are precision-machined at the factory as matched pairs and must remain together during installation to ensure optimal sealing).
Cam bearing surfaces must not have excessive wear or scoring. No stripped threads, no bent, cracked, or broken fins, no damage to gasket surfaces, etc.
Remove all components from your cylinder head leaving only the valves, springs, spring seats and cotters installed.
Keep all of your removed components. This includes: intake boot, cylinder studs, dowel pins, rockers, rocker shafts, rocker shaft retainer bolts, valve inspection covers, cam cover bolts, cam bore plug, camshaft, cam ‘C’ ring. (#3 and #6 thru #28 head diagram and #1 thru #15 valve diagram below) You will reuse all of these pieces to install your new big valve head properly.
What you send to us for exchange will be the head with valves still installed and the cam cover.
The big valve head we send to you will be ‘bare’ with only the valves installed and will include a matching cam cover. Use your original parts to assemble the head. If any items show significant wear now is time to replace them. We can supply any OEM parts you need upon request.
**Note:** If your cylinder head core features a notch cut into the top fin for the purpose of accommodating the installation of a stock petcock onto an IMS fuel tank, this modification qualifies as an acceptable core exchange. Please be aware that you may receive a cylinder head with a similar notch, which remains fully operational despite this alteration and will not impact the performance of the big valve head.
Upon processing your order, we will promptly email you a Return Merchandise Authorization (RMA) number for the return of your existing cylinder. If you do not receive this email within one business day, please contact us via phone/text at 541-688-9543 or email returns@procycle.us to request it. Please write the RMA number on the outside of the box. Pack it well to avoid any possibility of damage in shipping.
Please refrain from sending us your cylinder core without an RMA number, as we cannot guarantee a prompt and complete exchange or refund if this procedure is not followed correctly.
