Hi guys! My name is Chip, I'm from Birmingham UK. I've inherited this beauty from my late father and decided to restore it . I filmed everything and will be posting every wednesday evening on youtube here: playlist I finished the restoring process appart from finding new piston rings, uppon assembly i found out that the old rings were pretty worn out...2.5 bar on a compression test a,d found out that the pressure is lost past the piston rings in the oil sump, the loss is 80%, the engine starts and runs but i'd like to find new rings and replace them. heeelp! i can't find new rings anywhere. the engine name is GJ71A some pictures before and after restoring it: I loved this bike ever since i was a kid, I'd like to restore it and ride it as it is with minimal modifications.
Welcome Chip. Lovely little bike you have there. One of the best Motorcycle Museum's in the World is in your town. I could only spend a day there, so always wanted to go back one day. How are you guys holding up with the virus restrictions? Mad World.
Chip. You've done a cracker of a job bringing the bike back to life , it's like new . Any pictures of how it was before.
Great work. If you can get some accurate dimensions on the rings then might be able to use some from another model/make.
I was hoping someone would sugest that. here they are from the service manual: the first photo is me measuring the rings out of the piston decompressed on my work bench.
Cheers guys! as for the pandemic situation , for me this was it, i pretty much locked myself in the garage and fixed it.
that’s how the bike was when i decided to bring it over and fix it: and the last image is how it’s going to look finally once i build the body extension. my plan is to use my 3d printer to print a mould instead of clay so then i can apply the fibreglass to make the final panels.
but please please pretty please, if someone knows a place that makes custom piston rings, or another engine using the same sizes please let me know here. PS replacing the engine is a nono as i’d want to keep it original. PS 2 selling it and buying another one is not an option as this bike has huge sentimental value to me. PS 3 I do have the frame , wheels and bodywork from the donor bike and those will be an electric conversion in the next youtube serries
I posted a list of piston rings in your first post which has now gone missing. I wont do all that again but here are some 44mm rings that might suit. https://www.aliexpress.com/item/328..._expid=48a73986-935b-4493-a668-dc5eba77cb7d-3
that’s pretty much my whole lockdown with some days of going to work but I was on it for the past 2 months. I’ve soo enjoyed it, and learned so much in the process. This was my first ever engine rebuild, restoring a motorcycle really, first time painting with a compressor, spray paint sucks, i know that now , once you go compressor you never go back)
I am guessing you have tried all the usual English Suzuki suppliers eg Crooks Suzuki, Robinson's Foundry, Suzuki Classic spares, etc. Are there any ring makers still left in UK? You may be able to get a set made. These rings from China are made for a certain size piston and if you can measure the ring width and depth then compare to these you will only need to buy four sets of them. If they are close then a slight machining maybe necessary. https://www.aliexpress.com/item/328..._expid=48a73986-935b-4493-a668-dc5eba77cb7d-3 Have you looked for other engines that use the same 44mm bore eg Honda stationary/lawnmower engines (I think the four stroke brushcutter would be close to 44mm bore) or some of the mini bikes with small capacity engines. Every engine uses rings so there must be some available to suit your bore size.
the thing i can't find with that 139qmb engine is the thicknesses of the piston rings. I'll just order a set and see if they fit on one of my lose piston that i have left from my previous blown engine.
Well if you are not prepared to get on the net/phone and do the research then getting some Chinese ones and if necessary modifing your pistons to suit will work ok.
More than happy to share my knowledge, can you give me the bore x stroke and perhaps the thickness of the rings, top ring, 2nd ring and the ring pack I won't guarantee that there will be something out there suitable, but there's so many scooters and smaller capacity bikes all through Asia there's a good chance, and they will be OEM with any luck, so good quality OK, found the specs here https://www.motorcyclespecs.co.za/model/suzu/suzuki_gs250fw 83.htm bore 44mm I'll check www.hispeedpiston.com first the right bore size then we'll take it from there
I thought I'd hit paydirt with this video, but then realised it's yours loving the cute assistant, everyone needs a Doggo as supervisor
44mm bore is non-existent on hispeedpiston Not tot say there won't be a small capacity bike with that bore from the current era Honda CB125T is equivalent bore, ring thickness will be discovered by locating service manuals https://www.motorcyclespecs.co.za/model/Honda/honda_cb125t_81.html Rings for the CB125T available separately here https://www.aliexpress.com/item/4000908051604.html Several models of Honda into a more current era look to use those 44mm pistons https://www.ebay.com.au/itm/Piston-...125-CM125-CD125T-CBT125-82-99-T5/184271541074 I'd also be looking for a 44mm big bore kit for the CRF50 as it's 39mm and folks always want to be hopping them up from MOAR POWA One other avenue worth perhaps pursuing, it seems there is a GY6 50-60cc engine which may have an equivalent bore lastly @my67xr loves MOAR POWA from the little engines and may be able to provide guidance