'79 XS project by a mechanical newbie. (But hey, it was free)

[skids]

You can build one for about 20-30 bucks. 4 chunks of PVC 8 caps silicone 4 vac gauges and some vac line. It looks like bomb parts when your done....lol

Build what?

[motoman]

Build what?

Vacuum synchronizer Sid. He also needs to insert pilot jets into each of the four lines(synchronizer side) in order to remove cyl. pulses so the gauge needles don't flutter like crazy. For future use, just make sure hose ends with restictors in them are ALWAYS attached to vacuum gauge side and not to intake vacuum port. Switched the other way WILL greatly change vacuum reading on whichever one is hooked up wrong.

[stoneairsoft]

I feel I’m not at the point of synchronization yet.

Is the consensus that the valve stem seals are bad? And, if they must be replaced, is the rope-in-the-cylinder method a possibility for this bike, or not? I’ve seen a lot of videos showing it.

[DiverRay]

Did you try the flour to see if there was a trail of oil? A bad seal will usually show up as oil smoke on de-acceleration. The oil dripping from the bolt is probably something else.
Sync the carbs BEFORE you try too much, as they WILL cause problems if not. You could end up chasing something for weeks, and find it goes away once the carbs are done properly.

[stoneairsoft]

I've not tried the flour method as the bike has not been running and I thought I'd be able to see just by looking.



I think I've had a revelation. I think I've majorly messed up. After everything I've done...it seems like the timing is off. I've been reading through the butt loads of valve adjustment tutorials and found images not matching up with mine.


Here's the front/exhaust dot *barely past




Here's the rear/intake dot *barely past




Here's the view from the right side of the bike.




Here's the timing plate where the cams are currently located.



I'm ashamed!

[bikerphil]

Yep, with the cam dots lined up, the timing pointer should line up with the 'T' mark but you already knew that. Get it back in line and hopefully no damage has occurred.

[skids]

I hope you have no bent valves! Set it correctly and then check compression.

[stoneairsoft]

Are there any steps I can take to “realign” everything? I.e. how can I make sure intake matches up with exhaust? If I turn the shaft, won’t it keep spinning both unsynched?
And is there any way to check for bent valves with he head still on?
Grrr.

[skids]

Are there any steps I can take to “realign” everything? I.e. how can I make sure intake matches up with exhaust? If I turn the shaft, won’t it keep spinning both unsynched?
And is there any way to check for bent valves with he head still on?
Grrr.

You cant check for bent valves without either running a compression test, or without having the head off and checking for solvent leaking past the valves in the closed position. You can’t do a compression test with the valve timing on the C-mark (big trouble). As I think I understand it (and I may not), what causes bent valves is when the cams are misaligned causing the valves to clash against each other. Someone on this site said that it is not caused by valves contacting piston crowns. That said, and given you said the dots line up when at the c mark, you might be able to release the chain tensioner while holding the cams in position, and move the crank sprocket towards the T mark, slipping the chain on the sprocket. You would have to ensure that the cams do not move. It would take three arms, three wrenches, and a lot of luck.

Actually, I think I did something like that long ago. I remeber holding a cam in position (the exhaust?) and letting the chain hold the other cam (intake?) while manipulating the crank back and forth. It would slip a link one at at time. I think the crank sprocket had to go almost all the way around to get to the T mark.

Please don’t tank this as gospel, because it was long ago when I did it, and I don’t think it was the “proper way” and safe way to do it. Maybe someone else could chime in???

[DiverRay]

Easy way:
1. Turn the crank COUNTER CLOCKWISE(I know, the arrow points the other way) until the pointer is on the 20.
2. Turn BACK until the pointer is on the "T"
3. Loosen the cam chain tensioner so you have a little slack in the chain.
4. Walk the cam chain one link at a time over the intake and then the exhaust sprocket until the dots line up.
5. S L O W L Y turn the crank clockwise until the "C" is lined up and tighten the tensioner bolt.
You should only be one tooth off, but you may be two. Because of this only move each cam sprocket one tooth at a time.

[stoneairsoft]

Well boys....

I had a knowledgeable local small engine/bike repair guy who's done work for my neighbors stop by last night. We pulled the plugs, did a simple finger suction test for compression and he couldn't find TDC. Based on the cam positions, the fact that only 3 pipes got hot last summer when I had it "running" and listening to the video I had taken then, he suggested I cut my costs and part it out / sell it. I have to agree with him. By the time I took it down to the head, found the bent valve or other issues, not only would I be way over my head, I would be putting in a lot more money than it's worth. right now, I've probably put in a good $250+, (with gaskets being the most expensive buying the set) tons of time, and can say I truly learned a lot. I'd hate to go to all the work of stripping it down, just to find other issues I can't solve.

I'm wondering about advice for parting it out. Since I had it running and all the electronics looked good, he thought I should get a fair price for the TCI, tach, lights, forks, etc.

Is there a big enough market for these parts, or would I be better off "scrapping" it as a parts bike for somebody?

[skids]

Well boys...

Is there a big enough market for these parts, or would I be better off "scrapping" it as a parts bike for somebody?[/B]

You might want to take a look at ebay for the summation of the parts you want to sell. See what the final bid was (if you can) for parts. As a parts bike, you might only get $500 for your bike.

A bent valve is really not such an expensive thing to fix... You might even be able to use your head gasket.

[MaximPhil]

Hi stoneairsoft,
You have over 100 posts on this thread. What did you expect from a 40 year old machine? that it would take care of it's self?
You say it was free , well nothing is free.
You have had it running so it will work so why not spend a few $$ and get it running properly. It will be an awesome machine. A running bike is worth about $1500 so until you have spent that much you are not out of pocket.

Please do not 'part it out" that is for machines beyond repair. If you don't want it give it to someone who does. Remember it was Free to you.

Phil

[DiverRay]

I can't stick a finger in the plug hole and find TDC either! I use a pencil and turn the crank S-L-O-W-L-Y to see if I'm at TDC or 180 out.
Did the local mech want to buy it from you? or is he also about 30 something and used to "modern" engines?
This engine is one of the most reliable built. It really does NOT take much to pull the head and fix a bent valve. Probably eight hours and about $150 if you put in all new gaskets. If it's an older engine, '78 or '79, I can send you a good used valve. I just need to pull it out of the head in the garage.

[stoneairsoft]

Thank you for all the feedback. I’m interested in pulling the head eitherway to poke around a bit, so I may yet do that. However, I won’t even know what to look for for a “bent valve”. The local mech was feeling for suction/push, not trying to actually touch the valve.
Like I said, it’s more the fact that I’ve put in tons of hours, a few hundred bucks, & feel like I’ve hit a wall of knowledge/cost. The body isn’t in immaculate shape anyway, so I doubt it’d get $1,500 running well. Anywho, I’d prefer a bit smaller bike like a 750, as I’m not a large dude.

I do SUPER appreciate all the help this forum has given.