GS750ES 32k/mi ...how far would you take it down?

[Guest]

I'm gearing up to dig into my '83 GS750ES in January and I need some opinions on the engine.

The bike has 32k/mi and has been mostly sitting for at least 10 years. Last summer I cleaned the carbs and got it running fairly well, I'd turned the engine by hand first with extra oil in the case to try and lube things up. It seemed pretty free....no stuck rings or anything like that. Compression after warm up was 165/158/160/162 so that seems pretty good to me. It could have been warmer too...

The case has lots of corrosion on the outside and I'd really like to take it down, get it blasted and repaint/polish it. I plan to take the rest of the bike apart (LOTS of digital "before" photos!) to clean/polish/lube/repair/replace all the stuck hardware and stiff parts.

So... If I take the engine apart and bearings/bores ect look and mic out OK will I be OK putting it back together with the same parts? I want to have a look at the internals and clean up the look of the engine but I don't want to lay out the $ for rings/bearings ect if I don't have to.

I'd do this on a "low mileage" car engine but I don't know how 32k/mi compares on a bike engine or how GS engines like being taken apart and put back together.


And has anyone bought one of those stainless steel nut and bolt kits off eBay? I can already see that hardware is going to be a b**ch on this thing and stainless seems to be the way to go.

Thanks for your help, let me know what other info I can provide.
Mac

[Mario Padilla]

Dear Mac,

I have the same bike. Mines sat for over 14 years; when my first daughter was born in 1990. Have recently got it back on the road. Had to replace battery, oil, filters, tires, chain and one caliper. Had to rebuild carbs, calipers and both master cyclinders. Bike is now running and looking great but now has developed a fork seal leak (project for christmas vacation).

To polish case covers, you will only need new gaskets and oil change, change oil filter while you're at it. While you're in there, you can inspect the clutch. Otherwise, if it's running well, and doesn't make any unusal noises, I wouldn't tear it down.

MP

[oldschoolGS]

Unless you absolutely want to split the cases, I would not touch the bottom end. Clean it up as much as possible without pulling it all the way apart, Pull the head and get it refreshed with cleaning and valve stem seals, and if cylinders are that good, you could leave them alone. At 35k and with a stock top end your cam chain should be OK. Have your cam sprockets slotted so you can degree the cams and reassemble with a manual cam chain tensioner. You are also looking at a drive chain, tires, brake and fuel line replacements if it has been sitting that long.

These were great bikes, I have had a blast on mine thru 45,000 miles since new. It has taken everything I have thrown at it thru various motor configurations and always hauled a$$.

A cheap and easy mod is to use 700cc pistons off the tariff bike- they were domed to make up for the compression loss of the de-stroked motor and will give 10.25-1 in the 750cc motor. Also, early air/oil GSXR carbs work really well- I have used 1986 GSXR1100 34mm flatslide CV carbs for many years- they are plentiful and easy to tune.
.325 - .350 lift cams work well along with a 4-1 pipe and aftermarket ignition. These bikes, when tweaked right, will really perform.

I bought one of the ebay SS bolt kit for my winter rebuild- it appears to be a quality replacement.

Good Luck, Ed
1983 GS750ED

[Macmatic]

Thanks for the info guys.

I think I'll do pretty much as Mario said and just remove and clean the various covers without going too far into the engine. I'll likely pull the head to clean the chambers and do the valve seals. Any reason NOT to lightly recut the seats and lap the valves while I'm in there? Anything special to look out for or check for?

I REALLY want to take every nut and bolt of it apart but since I've got another 16v GS750 engine that I picked up for $50 I guess that one can be the test subject.

At this point my plan it to get the bike road ready over the winter and ride it for a season before making any mods....even the 4-2 exhaust will stay for now. Then again by mid summer I'll be living in Atlanta so I don't know if the season will ever really end. 8)

"factory Manual on the way"
Mac

[SqDancerLynn1]

If the $50 motor is good I would put it in the bike and redo the original motor during the next year

[kevan]

My 84 GS750 has 177,000 kms on it and still runs good. The clutch is tired and needs replacing but other than that, it keeps going.

Kevan
GS750

[Macmatic]

The $50 is unknown other than that it turns over with a wrench and is complete. I'm not even sure what it came out of other than that its an all silver (not painted) TSCC 16v 750.

I think the engine in the '83 should prolly be fine, given the compression and how well it seemed to run after I went over the carbs making only base settings. I don't have a factory manual or carb synch as yet. I just want to dig into it because its new to me...and I want to make it all purrty. heh

Good holidays y'all! (I'm practicing for Atlanta)
Happy New Year,

Mac