Hello everyone hope everything is going good staying warm at least. I have a 1973TX 650 that needs a third gear so I have to split the case When I have the case apart. I thought I’d freshen things up. I don’t see a big bore kit. Or any rebuild kits. On any of the usual sites selling XS parts I talked to pandemonium and I would love to have him rebuild my motor.. in which it sounds like he does an awesome job but the funds for this project just aren’t there. however, I thought I could purchase a new, set of heads And make it a big bore kit and kind of do a rebuild. I haven’t tore it apart so I don’t know what the crank would be like. It has a little bit of smoke from the left side but nothing to complain about so I don’t think the motor is in bad shape. It has a good compression And starts on the first kick so I probably should just leave it alone but we know how that goes. And just change 3rd gear I am unable to find anybody around my house. That’ll do a valve job or bore the cylinder for me. so on the machining side I’m kind of stuck that’s why I thought I could buy a new set of heads. How hard would it be to put a later model set of heads on it? Plus they would look awesome , nice and new I’m sure somebody’s been in the same boat. Any advice would be appreciated. Merry Christmas and hope everybody gets a bunch of bike parts. Thanks again.
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1973 TX650 big bore kit? Or just freshing up things
- Thread starter jjohn3845
- Start date
You don't have to disturb the top-end to get to the transmission. You access that by removing the bottom case and the top-end can stay intact. However, there is something to be said for rebuilding the top-end while the motor is out of the frame....
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If you want to big bore, find a 447 motor then: https://yamahaxs650.com/product/447-big-bore-kit-80mm-750cc/
Being a 73 tx650 I think they had 22mm pins so this kit won't fit,
I looked through the site, they have some interesting stuff on there, mostly out of stock, the only thing that would worry me is there is absolutely no contact details or any form of address on there, I almost got caught out before and several international buyers did on a website years ago, luckily he had a phone number on there so I was ringing him constantly until he sent the items, but still took around 3 months to get them.
Why i said find a 447 motor..........
That site is the original Mike and or his wife, I've gotten 4 or 5 of the big bore kits from him and got other parts recently that shipped quickly.
For background; https://www.xs650.com/threads/big-bore-big-block-kit-i-just-found-on-a-new-source.59061/
Short version; The site is selling off a large inventory of XS parts, is/was not designed to be an ongoing business.
Some, much? of that inventory was sold off to other XS parts vendors.
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Appreciate the link, just ordered one myself. Bought a complete bottom end from Gary Hoos earlier in the year, this should go a long way to finishing it off.
I too have an older 256 series '73 engine that needs refreshing but have despaired being able to properly do it because of part unavailability. Hoos told me that any electric start engine will fit the frame mounts so have been putting together parts for a newer replacement.
I too have an older 256 series '73 engine that needs refreshing but have despaired being able to properly do it because of part unavailability. Hoos told me that any electric start engine will fit the frame mounts so have been putting together parts for a newer replacement.
Thanks for the response. Quess I need to find a newer engine then have fun with it!! As much as it pains me to just fix the gearbox. That’s what I have to do. Then start finding parts for new engine. I do have a bunch of take off parts for this moto. Like alternator starter compression release bunch of electrical stuff if anybody needs it.
Here’s a photo of my proje. I’m pretty happy with the way it rides other than kicking out of 3 gear. I didn’t know any history why the bike was parked along time. So I gambled and spent the money on everything els. I know now why it was parked.
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The usual reason why they spit back out of gear is because of rounded-off gear dogs. That in turn is caused by ham-footed, cloth-headed owners who change gears without using the clutch, for thousands of miles. That might be why the PO laid it up.
The PO of one of mine was a rider like that, and when the bike started spitting itself out of second gear I asked him if he was a clutchless changer. He asserted he'd been doing it for years and never had any trouble. Yeah, until I bought the bike - and about two or three thousand miles into using it, the trouble started.
Funny a friend of mine was making fun of me for clutching my Indian. It just seems wrong not to clutch it. Race cars are built with straight cut gears for that reason. And in turn they won’t shift with out lifting the throttle. I’m not sure but I don’t think most motorcycles have that kind of technology in place. I’ll just keep trying to respect the equipment I ride. Shits to expensive to hurt anything and I don’t want to work on it because it’s my fault.
3 to 4 and 4 to 5 upshifts are pretty easy with no clutch 2-3 is just a bit trickier 1-2 and 2-3 can be done but "not worth the risk", same with down shifts.
But I grew up driving transmissions with non synchro first gear. And lived with more than a couple with a weak synchro on 2nd.
But I grew up driving transmissions with non synchro first gear. And lived with more than a couple with a weak synchro on 2nd.
