1976 GS750 Clean and Rebuild

[shryke300]

Help!!!!! Valves and cylinders

Ok... So I have two separate issues: valves and cylinders. First things first.... I contacted a guy about hot tanking and reseating myh valves. He wanted $150. Good price? The real problem though, is if my valves are still good. Can anyone tell from the pictures below if the valves are pitted? any other issues? Or is there too much carbon buildup to tell?






Now.. My second issue are the '79 850 jugs i got off of ebay. It does not fit. I am going to assume this means the posting was not entirely true. It looks like the 1 and 4 cylinder sleeves are contacting a ridge on the inside of the case. Is this what everyone refers to when they talk about grinding the case to clearance the '80 850 jugs?





If anyone can help, please respond...

[shryke300]

Been slowly working on cleaning the cases and acquiring parts. .. I should have some pics to upload later this week. I do have a quick question about the 850 swap. I think I have a 1980? The ad on eBay said it was a79, nut I had to grind the inside of the case to get it to fit. Do I need new carbs? Will my vm26's work? Or will I have to get some cv's? Also, any way to tell what year I have?

[shryke300]

So I've done a little work since the last time (not much though). So far I Cleaned all the carbs again (boring) and have painted everything with por-15. The first time I just did the covers and they looked amazing until the last coat. I was doing it with a brush and did not get good enough coverage. so.. I sanded it down and shot everything with a spray gun today. Some of the stuff looks really good, some does not. I think with por15 if you know what you are doing, it looks AMAZING. However, I have painted anything with a pray gun before and evidently did not get the settings right or put enough solvent in it. I had a lot of issues with the spraying and will have to do some of the parts over again. I think I will do touch ups with eastwood. Don't get me wrong, por15 on a couple of parts looks like liquid molten gloss black lava (sorry, don't have pics). It was BEAUTIFUL, and their tech support was great. I just don't think my skills were there. Until I get more practice with a spray gun, I think I would use the eastwood products. It is now time to start putting things together.




With respect to the 850, here is what needs to be ground on the crankcase:


This is it ground:

[Sandman900ss]

I like how you're working on this one. Sorry I can't help out about the 850 cylinder issues. One thing- what was your prep before painting the cylinders and covers with por15? Just thorough cleaning? I would have prepped by either bead blasting, vapor blasting, or soda blasting- this is too big a job not to have super clean surfaces to paint. The cylinders and heads look fantastic, but the clutch cover has too much orange peel in my opinion.

By the way, for cleaning around the countershaft sprocket area, I always go with a gallon of K1 kerosene in a bin, and an automotive parts cleaning brush. Cheaper and more effective than WD40, which is 85% kerosene anyway.

[shryke300]

Thanks for the help! the kerosine treatment is a good idea. I had a soda blaster and was going to shoot it, but got scared off by all the risk google said it had. To prep, I wire brushed as much as i could with a wire wheel on my drill, scrubbed several times with Dawn and scotchbrite and brushes, then clean with simple green then clean with por15 degreaser with rubber gloves on. I don't think the prep work was the issues, I know I was not spraying it well and now don't have enough to fix everything. I will definately do something with the side covers, though. I think they look terrible, as well.Stay tuned! BTW, i'm open to all help!

[shryke300]

Does this look OK?

I thought about making a tail that was little shorter than my last one. One kind of like this:

http://houseonfireindustries.com/2012/05/20/gimme-the-loop-yamaha-xs650-cafe-racer-seat-build/

However, I put my old tail on and it looks like this:


This tail would need a little work on it still, but could do the duty. Opinions? I think the longer tank helps the tail be a little more proportional. I think it may work well, but ..... I would like opinions. Which way should I go? will the old tail look good (not just OK)?

[shryke300]

More Options

Option 2:


Option 3:


Option 4:


Final Option:


So what do you think?

[shryke300]

Shocks

So... I like the stance of the bike and to keep it, it looks like the rear shocks would have to be about an inch longer. Would this cause any issues with the chain? Anything else I might not have thought of...?

[shryke300]

Does anyone know what these parts are?

[cowboyup3371]

They are the brackets for inside your stator; they'll cover and protect the wiring.

[Chuck78]

Wow cowboy, I would have not guessed that one, good eye!

If you raise your rear shocks, it will increase your rake and decrease your trail on the forks, so the steering will be affected and will respond differently. It will turn in much faster, but due to not correcting the changed trail measurement with a different offset set of triple clamps, you will lose a slight bit of high speed steering stability. I gathered that this is why a lot of modern sport bike forks have much greater offset to the triples, because they have much steeper rakes (head tube steering angle). trail is something you will have to look up for a visual description, centerline of the the fork legs at the rake angle to an imaginary line on the ground vs the imaginary line on the ground directly below the axle perpendicular to the ground as opposed to the line that the fork legs point at that is ahead of the axle at ground level. Basically the difference between the center of the tire contact patch measured to the center of the axle's perpendicular axis to the ground. adding a steering damper (dampener?) or stabilizer is a bandaid to cure woes of altered trail and steep rake. Modern sport bikes come with them even when they have the factory engineered rake and trail, as they are set up more aggressively for fast turn-in (especially to make up for the monstrous and slow turning characteristics of a gargantuan 180 rear tire...
Basically a proper amount of rake and trail is needed to balance out the high speed stability vs low and medium speed turn in characteristics. the offset in the triples (and the axle position on leading axle forks) is what dictates the trail. Less rake and more trail makes for more straight line stability but slower or harder turn in characteristics. More rake and less trail does the opposite. Therefore a good balance of both is what is ideal.

Please correct me if I am off base, anyone.

[Guest]

A little help

Photos supplied by Eric. (your stator wire brackets and routing)


The answer to your black bolt question. It keeps the shift mechanism in position.
It holds the return spring, which returns the shifter back into position for the next shift.

Diagram from Bikebandit's website.(item #27)

[shryke300]

You guys are awesome. I thought I had labeled everything well when I took it apart, but left those out! I have done a couple of things and hope to have more pictures coming soon!

[shryke300]

Tried to get the jugs on today. Going pretty well:


Until this happened:


This happened on both the outside pistons, both the bottom oil ring. I have old ones that worked, but I don't think I should use them, so I guess its now another $35 a set.

[Fjbj40]

Those look like Athena gaskets!?