Hi guys, I'm in the process of rebuilding my GSX250S COBRA. Sadly, I ****** up the cylinder head after it was fresh out of the machinist's shop, and now I need a set of (actually 4 sets) of intake valves. Here are the part numbers: Bandit GJ74: Intake: 12911-06c01 Exhaust: 12912-06c00 GSXR250 / COBRA GJ73: Intake: 129911-06c00 Exhaust: 12912-06c00 So the question is: are the intake valves actually similar / interchangeable? Has anybody actually ever tried this? Measurements below for the GJ73 intake valve: Face diameter: 19mm Length: 80,3mm Stem thickness: 3,70mm Thanks!
I don't know but often just a "1" on the end is often an update of some sort. Can you just buy one and compare them?
Additional number on the end denotes updated part. Generally the new part will replace the old without a problem, but not sure that the old can be exchanged with new. Usually the part that is superceded will not be made or sold after the updated part is available.
I'm currently after second-hand valves. I have a source, I gave him the measurements, he already found two, and promised to dig for more. We'll see. You're right. I checked CMSNL for 12911-06c00 and it shows it being superseded by 12911-06c01. So I guess this is sorted Btw, the chinese valves mention both GJ73 and GJ74: Aliexpress link
FWIW - different valves for a different machine, but may help you in purchasing valves with the proper specifications. I bought a set of CBR250R MC22 valves from Aliexpress - they look to be good quality, well made, concentric and consistent in the stem length and head diameters. HOWEVER their stems are enough below the proper diameter (new) that you couldn't put then into used guides as the clearance would be too large. They're so close to wear limit as they are. There are other issues with them as the collet retainer grooves aren't in the same location as OEM valves - that doesn't affect my intended purpose, but the spring set length would be wrong (too short) on a proper MC22 install. AHL parts on Aliexpress seem to enjoy a good reputation for quality AND correct specifications of their parts. From that I searched for them on the Official AHL Aliexpress page, and MC22 valves weren't available at that time from AHL. So if they're available on the Official AHL Aliexpress shop, and perhaps a little more expensive, they may be worth the extra cost. https://www.aliexpress.com/item/2006551641.html Both stores are using the same pictures for the valves. I hope I haven't created confusion...
Okay, so it seems that AHL doesn't make a valve kit for the 250 inline4 suzukis (Bandit, Cobra, GSXR, Across, etc.) - edit: oh gosh I didn't open the link you posted before writing this. So after all there _is_ an AHL valve kit for these bikes: AHL (Aliexpress' search engine sucks, and also it doesn't help that sellers don't use consistent naming, e.g. GJ73, GJ 73, GJ73A etc. There are other sellers who have them: Road Passion Motorcycle Quality Parts Store OLUMT ZZYS High Quality Motorcycle Parts Store BLMT ASDL Zesu Motorcycle Part Store Based on the ratings, reviews, Road Passion seems to be the most reputable seller. They've been on the site for the longest time, and they have the highest rating.- edit: might be the next best thing to AHL. Btw, cylinders have been overbored, and I installed AHL oversize pistons and rings. I already heard it run with good enough compression (9-10bar across all cylinders) before I screwed up the timing. So I guess I might be among the first ones who bought chinese pistons, used them and lived to tell the tale. Nevertheless, I already designed a warning label that I'll put on the bike that says "This vehicle is built with pistons made in China, beware of flying engine parts" )))
I have been using the AHL valves, gaskets, pistons and rings in CBR's and ZXR's with no problems for about six years now. The reborer even commented on how he was surprised at the consistancy of the sizes across the four pistons. Road Passion also has supplied quite usable parts.
Looks like Road Passion have equal attention to product quality as AHL - I've got a set of 48.25mm O/S FZR250 pistons that measure 0.016 spread between them smallest and largest which is well within OEM spec, each piston is within 0.008 or lower of 48.25mm BTW I use google to search aliexpress - the aliexpress search just throws up hundreds of random results, literally hundreds and hundreds... I just type "whatever I'm looking for" and aliexpress for decent hits - life is too short to wade through all of aliexpress otherwise
