BananaSplit

appreciate everyone chipping in to help out. when we get started I will share some images on a dedicated thread. thanks again.

yes potentially, but the Wiseco 816 kit seems to be a tried and tested option at 70mm. and the kit covers pins clips gasket and rings. it's not the cheapest choice but will probably be the best option in the long run. less thing to worry about in the engine overall.

well yes that would be an easier approach in some sense. What I am aiming for though, is to rebuild the 750 ES engine to its potential, while still keeping reliability in mind. Not so much just having a bigger engine. The boring is really out of necessity given there are 90k kms on this bike so far, and it has already been bored once to +1mm. Most other parts will be stock OEM where possible. Though I will be running some 34mm Mikuni RS carbs with stacks. If I throw this engine out at this stage I doubt anyone else will pick it up, and it will be the end of it's life, 30 years on. And that would be sad.

tracking down some NOS camshafts as well atm

ye stripping the whole thing. I will see if I can track down the chain guides as well. They might be harder to find. I think the D.I.D chain is endless. Though is doesn't specifically say so, they do quote the original OEM number, and the OEM would be endless. It also says you can purchase a master link separately if you need to separate the chain. Safe to assume it is endless I would think. Shame, I was hyped for a HY-VO chain ha! its a D.I.D 219FHT Bush Chain - for reference

thanks for that! on the same note, anyone here know of any worthwhile cam chain swaps? I don't want to go through the trouble of finding new new gears as such unless there is a tried and true alternative. I initially read that the bike had a HY-VO chain, but the writer must have made a mistake, it doesn't. DID make a OEM chain, but was curious what was involved in using either a silent or HY-VO. Any advice? Should I just stick with the OEM?

thanks so much, this is the kind of advice I was hoping for from here, this good that bad etc, since this is the first time I'm doing this. Clutch plates are on the list. So are valve springs and basically all the bearings on the whole bike ha! I always try to track down OEM, I just hope they are still in supply in some corner of the interweb. I'm really hoping the crank is in good state, Still haven't pulled anything apart yet, trying to get it registered before we break it down to avoid the hassle of explaining why the bike doesn't look stock. Looking for a crank will be a real bitch...

Thanks for the heads up, it might be easier to go with the Wiseco for now, give it works with the 750ES. Just hoping it still incorporates the TSCC system the stock pistons have.

As stated by other members, first thing I recommend you should do is get the manual printed out, the entire stack. It will tell you how to diagnose most common issues. I just got a 83 750es as well a couple of weeks ago, which I am working on with a friend who is much more experiences than I am with bikes, and trying to learn something in the process. If you send more images I can compare the wiring to what we have here, but given it's a project bike you have taken on, there is a chance the wiring has been messed with previously. Happy to help whichever way possible, did you check your kill switch? I will have a look tomorrow when I'm at the garage if it hasn't worked out by then. Manual will tell you which wires do what as well.

thanks for the advice, I didn't really know what you meant about the cams but did a bit of reading and all makes sense now. That is a good idea, I might get some OEM cams and get them worked on to get a bit more lift to the larger capacity. appreciate the help. Yes, will be running a custom stainless exhaust. will be building this at a much later stage though, still sourcing parts for the engine. The donor bike has 90K km on it. Don't want to take a chance.

yeah found an 816 piston kit, was just wondering if I could optimize the higher capacity with some top end upgrades. No luck finding anything specifically for the ES. Yeah that might be possible. I will cross check if it would fit. Thanks for the insight.

Anyone here have experience upgrading their 750es engine? specifically cams, rockers, valve springs? mostly looking at the top end.....

so after spending two days searching the interweb, I think I have it picked out. This seems to be the biggest cause of confusion. The Wiseco kit that I have settled on is the k816 70mm (+3mm OS) 10.25:1 cr. I actually came across a video of a guy rebuilding a 750 ES and caught the Wiseco piston part ID off the packaging in the background. No luck here either unfortunately, all US distributors seem to quote the gs. The couple of UK distributors mentioned the gsx. Thanks for the help. Hopefully might help someone else looking for the same info. If anyone else knows something I don't please let me know.

yep, but the gs750 listings have both a 4 valve and 2 valve option as two separate kits. And yes its a 810cc kit. I am just a bit confused but I think there was a 80-83 gs750 4 valve model that might be interchangeable with the gsx 83-86?

Hi All, Curious to know if anyone had experience upgrading to oversized forged pistons? Was looking for something that would work with stock rods and gaskets. 70mm Wiseco pistons are available for GS 750 models (4188M07000), but I know the valve sizes were updated for the GSX in 83. Are the pistons interchangeable? Was hoping someone would have suggestions on what would be ideal.