TX750 Info

[xs650newb]

Hey guys,

Friend picked up a TX750. Read a lot about these bikes, some on this site.

I know its the readheaded step-child of the Yamah family. Made only for 2 years. My friend has the 73, which I know has plenty of technical problems.

We're trying to get it running. Carbs are cleaning and its getting a spark. Haven't checked the timing or compression yet but it def. wont start.

My question though is about the kick/electric start.

The electric starter doesn't do anything, even when I bypass the solenoid.
The kick start is VERY VERY had to kick. It makes a weird noise on the down stroke. I cannot stress enough how hard this thing is to kick.

Any idea what is going on? Something out of adjustment?

Also, anyone know what the deal with the points ignition are on this bike. I think its behind the left side cover. Is there oil behind that cover?

Best,
Adam

 

[650Skull]

Can't answer your question but here is a thread from a member who restored one.

Thought i would get in before the flame throwers arrive

A couple of links for you.

1

2

3

 

[5twins]

Sounds like the motor's shot. The '73 models had an oiling problem that could lunch the crank in as little as a few thousand miles. I'd find out if that's what you've got going on here before spending any money on the thing. On the bright side, they make a nice parts donor for the 650, lol.

 

[xs650newb]

Thanks for the replies.

5twins,

I am aware of the oiling problem. Any good way to confirm the crank is shot without opening up the bottom end.

Like I said, the bike is very hard to kick and makes a very weird noise when doing so.


Adam

 

[XSLeo]

Do you have a repair manual? If it was mine I would read up on just how the kick start and e-start should work.
Then pull that engine out and set it aside. install an XS650 engine with a 750 kit installed.
But that's just me.
Leo

 

[xs650newb]

I don't. Bike isn't even mine. Asking on behalf of a friend. He got the bike, couldnt start it, and asked me to come over and have a look.

Do 650 engines bolt right up?

Best,
Adam

 

[XSLeo]

I'm not sure, but modding mounts shouldn't be any harder than rebuilding the TX750 engine. Probably cheaper too.
Leo

 

[CalsXS2]

WOW. How did I miss this!!.........LOL.

Sounds like you got the trashed motor blues. Maybe it's just tight from setting.

I'd start soaking it with PB Blaster and see if it gets any easier to kick.

As far as the starter goes, read this complete thread I'm going to link to below. It's a little tutorial I wrote about a starter clutch mod I installed that a guy named Argo from Estonia came up with. Besides the dreaded engine failure, if you got one to survive,, the starter clutch's were junk. Mine now starts with just a touch of the button. There's some before and after video's too.

There is an inner and outer cover on the left side. I would pull both of those to get to the starter chain. Then you can see if it's even trying to engage. You may have a bad starter motor if you aren't even hearing a noise.

Post some pic's too.

BTW.

5twins. I'm disappointed. You didn't even give him the swing arm and rims line.

http://advrider.com/forums/showthread.php?t=908967

 

[xs650newb]

Thanks for the reply.

I will go through that thread.

Kicking it is super hard and it kicks back almost every time. It hurts very very bad. I'm thinking the timing is off.

Anyways, you mentioned to let it soak in PB Blaster because it might be tight from sitting. What are you referring to?

Best,
Adam

 

[CalsXS2]

I was referring to rusty ring's.

Have you tried kicking it with the spark plugs out? Any easier?

 

[xs650newb]

Ok. As far as I know the rings are fine. My concern is that kicking the bike is exceedingly difficult. When going through the downstroke on the kick the engine also makes a weird noise. You never really feel the compression stroke come on. It is a constant, smooth resistance when kicking.

How can one tell if the crank is bad?

 

[CalsXS2]

Ok. As far as I know the rings are fine. My concern is that kicking the bike is exceedingly difficult. When going through the downstroke on the kick the engine also makes a weird noise. You never really feel the compression stroke come on. It is a constant, smooth resistance when kicking.

How can one tell if the crank is bad?

I'm not going to lie to ya..... I don't know that one myself,,,,lol.

I think these thing's just locked up from oil starvation. Or they stated hammering.

Here's a couple of good source's for the TX750. You can go to advrider.com,, scroll down to "old's cool" and start a thread there. There's quite a few TX750 guy's on that site. There's also a facebook page called "yamaha tx750. A lot of guy's there too.

I'm sure between them,,, someone would know the symptom's of a bad crank.

 

[5twins]

I never should have mentioned the swingarm and rims to anybody. Now I can't buy them cheap anymore, lol.