Back working on the 71

[curt698]

Back working on the 71 **HELP NEEDED**

Well kids and going back to school side tracked me from the 71 but I finally got it started and road yesterday for the first time this year. Last year was the first time the bike ran since 74 and first time ever since the bore to 750. Last year the bike ran alright at low speeds but never got going on the top end. This year I took the main jet from a 135 to a 142.5 (i think). Now I still think the idol is a little off but it pulls stronger up high.

OK so things that still need sorting out:

1. At low speeds it is very twitchy, almost like a two stroke. I have not ridden a 650 so I don't know how they act. The twitchy-ness may just be all the torque from the bore???
2. Lots of top end rattle or tapping. I bought a set of feller gauges and attempted to adjust the valves but having never done it before don't really know if it is right. My guess is that the cam chain is lose. I'm not sure how to fix that yet, help would be great.
3. All the wiring from the left controls broke right were they enter the head lamp so that needs to be re-wired.
4. I need to fix the three things that are going to break riding today.

Thanks for any help,

Dave

edit: Any advice on the tapping or twichy-ness????

 

[curt698]

bumped for help, PLEASE!!!

 

[jamesgs4]

I think the lack of responses is due to your odd questions.
first off, get a free manual at www.biker.net
1. Do you mean the throttle response is touchy? Also, what is torch from the bore?
2. The valve adjustment is to be done on a cold engine at exactly top dead center. Also note that yamaha factory manuals list the measurements in mm, not inches. These older air cooled engines are louder and more mechanical sounding than modern engines, so it is hard to know how much tapping is too much without hearing it in person.
The factory manual goes over the cam chain adjustment.
3. Yes, fix the broken wires.
4. Yes

 

[curt698]

Sorry I suck and spelling and think faster than I can type. Torque from the bore was my intent. I was also hoping for a hint or two on the cam chain thing being an extreme novice. Thanks for the reply btw.

Dave

 

[retiredgentleman]

This is how I do my camchain adjustment. I take the bike for a 15 minute ride, so the engine is hot. I remove the nut from the camchain adjuster (yes, its easy to burn your hand/fingers).

Start and with the engine idling, using a 10 mm wrench, adjust until the in/out motion stops (which is too tight), then back out 3 flats of the adjuster nut (in/out motion starts again). That gives sufficient in/out motion.

Your 71 has a different camchain adjuster than my 78SE I believe, so there may be some variation in how you do yours, but the principle is the same.

 

[curt698]

Thanks kind sir, that helps a lot. Got a bad feeling that adjustment may not be enough