1977 GS750e project

[jibledso]

Just had a consultation with John and it looks as though I’m to have to Mill the head because there is an imperfection on the bottom of the head, John spotted it, it’s like a scratch but not a crack. So, if I do that I’ll have to Mill the top of the jugs and at least hone the cylinders.

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[jibledso]

John also questioned the color of the top of the pistons and combustion chambers. To him they shouldn’t be as dark and more light.

he also thought the cross hatch was not prominent enough

8FD8C477-5167-4DF4-9179-CD1825520A4B.jpg

[Chuck78]

Just had a consultation with John and it looks as though I’m to have to Mill the head because there is an imperfection on the bottom of the head, John spotted it, it’s like a scratch but not a crack. So, if I do that I’ll have to Mill the top of the jugs and at least hone the cylinders.

[ATTACH=CONFIG]57512[/ATTACH]

you don't have to mill the top of the cylinder is just because you mill the head.
it is perfectly acceptable to do one and not the other, but if you do both, you know you will have a really good sealing surface. And higher compression ratio by a slight bit. That will more than make up for cutting the valves in deeper which would increase the combustion chamber volume slightly.

Also, where is this defect in the cylinder head? If it is not around the four outside corner cylinder studs, not around the cylinder bores outside of the combustion chamber where the sleeves seal to the head, and not around the cam chain tunnel, then there is no need to really worry about it at all. The only thing you need to worry about is warpage. You need a machinist straight edge and feeler gauges to check the warpage diagonally across the head.

[Chuck78]

Does anyone at your shared garage have a milling machine and a very large heavy fly cutter attachment? resurfacing the head and cylinders is not difficult at all with the right tools, but the difficult part is getting everything fixtured up in place and clamped down properly, and perfectly parallel to the work deck...that is all the labor there, and that takes quite a while.

John also questioned the color of the top of the pistons and combustion chambers. To him they shouldn’t be as dark and more light.

he also thought the cross hatch was not prominent enough

[ATTACH=CONFIG]57513[/ATTACH]

Did you tell him that you have low compression, and that you are burning oil, before he commented on the color of the carbon? Those two things alone would definitely make it black and sootey. so would neglected air filter maintenance or riding at higher altitudes than what the bike was jetted for.

Having a noticeable bit of cross-hatching would be nice. it helps to hold oil up on the cylinder wall, and is important to have a cross hatching done at opposing 45 degree angles. But if you do that, you will definitely want to put in some new piston rings.

At that, you might just start shopping on eBay for useable 850 cylinder block and pistons for cheap! You will have to grind a little on your crank case fit them, however. this can be done without tearing the bottom end down if you really don't want to, just turn the engine upside down and stuff the holes full of rags, not letting any metal shavings get into the crank bearings at all.

[jibledso]

you don't have to mill the top of the cylinder is just because you mill the head.
it is perfectly acceptable to do one and not the other, but if you do both, you know you will have a really good sealing surface. And higher compression ratio by a slight bit. That will more than make up for cutting the valves in deeper which would increase the combustion chamber volume slightly.

Also, where is this defect in the cylinder head? If it is not around the four outside corner cylinder studs, not around the cylinder bores outside of the combustion chamber where the sleeves seal to the head, and not around the cam chain tunnel, then there is no need to really worry about it at all. The only thing you need to worry about is warpage. You need a machinist straight edge and feeler gauges to check the warpage diagonally across the head.

It’s in between #3 cylinder and a stud not seeable with my camera, John spotted it, he’s machined a lot of heads and was kind enough to show me how to recut the seats with his nice set but he didn’t have a rod small enough to fit into the valve hole to attach the cutter.

We were discussing machinist in the area and we narrowed down two who are quality. I’m going to call and discuss what could be done and how much. John thanks for my needs I could do it for 4000-5000 kroner, so the most would be $500 to Mill the head and jugs, cut the seats etc. if the cylinders meet the standard I’d probably try and get by with a hone and new rings.

One good thing, I’m standing in a lobby right now for an interview about a tire changing job, money flow looks emanate in the near future to get this bike I love back on the road.

[jibledso]

Does anyone at your shared garage have a milling machine and a very large heavy fly cutter attachment? resurfacing the head and cylinders is not difficult at all with the right tools, but the difficult part is getting everything fixtured up in place and clamped down properly, and perfectly parallel to the work deck...that is all the labor there, and that takes quite a while.

Nope, no milling machine in the garage. I was hoping for a simple seal replacement and valve lap before I took off the head since it ran well except for the smoke, which I never noticed the first month I had it, no smoke, ran strong, so seeing with the head off was a surprise. That carbon/black build up was all before I took owner ship. I didn’t really get to ride the bike enough to determine if it was using oil, but I definitely would of noticed the amount of smoke coming out now.



Did you tell him that you have low compression, and that you are burning oil, before he commented on the color of the carbon? Those two things alone would definitely make it black and sootey. so would neglected air filter maintenance or riding at higher altitudes than what the bike was jetted for.

Yeah, actually John was there when I started it the first time since adjusting the valves and putting on the pods. He helped getting the bike to idle without dying, we also hooked up a glass spark plug to see the color of the flame, and they turned out well, then I took it outside and rode around the block (still not operating temperature) came back let it warm up then LOTS of smoke, idle, and more on exceleration. After that we did the compression test, dry and wet and we both felt it must be the valve seals since the compression wasn’t horrible. Also, the case pressure checked out while it was running, no oil was being pushed up by the rings.

Having a noticeable bit of cross-hatching would be nice. it helps to hold oil up on the cylinder wall, and is important to have a cross hatching done at opposing 45 degree angles. But if you do that, you will definitely want to put in some new piston rings.

At that, you might just start shopping on eBay for useable 850 cylinder block and pistons for cheap! You will have to grind a little on your crank case fit them, however. this can be done without tearing the bottom end down if you really don't want to, just turn the engine upside down and stuff the holes full of rags, not letting any metal shavings get into the crank bearings at all.

Yeah, if I was still living in the States I’d be all over some 850 jugs but it’s more expensive to get and ship unless I find some here in Sweden. I was quite happy with the 750’s performance when I rode it, actuality I was surprised after riding a GSF1200 for five years in the States.

Will see what happens in the near future with work and money. I have a definite job in the middle of April doing landscaping till October. I had two different car tire businesses call Friday, both just want one month of employment which fits nicely with the other job. In Sweden you have to have studed tires from November to March legally after that it’s summer tires so it’s a busy time of year for these businesses. Maybe within a month my budget can keep up with my hobby.

[adalah]

Subscribed to this one

[jibledso]

Well, Jesus, where do I start?

It’s been almost a year when I started my GS750 and it smoked like a freight train and I felt like throwing it in the water. Through some discussion with other people here my best guess is that I used synthetic oil which by passed the valves etc. entered the combustion chamber and poof, smoke. More than likely if I’d just put in mineral non-synthetic like it had before I’d be riding my bike now.

I called basically the only guy who has old GS parts in Sweden and tried to figure how I should start overhauling the top-end. Took the heads and pistons to a machine shop to await the parts to come in from said Suzuki parts guy. Over the phone we determined; 1. He had an all new GS750 head for me for $300 2. I would have to get new pistons and hard ware etc. 3. After buying the parts and paying the machine shop it would cost close to $1,000. I said verbally over the phone yes and send me the parts. That was back in April or May. I thought after summer the parts would arrive. Haven’t heard anything yet. Last month the machine shop called and said come get your heads, we measured everything, that’ll be $200.

The first thing I need to do is call parts guy if he ever answers the phone and see what’s up. Then I’m leaning to just buying parts off eBay from the United States because frankly I’m beyond tired of not having a functioning GS750 for three years now.

Good news is I’ve been working steadily as a landscaper all summer and fall. However, I’m going to be a father in December so like most of us know your priorities change and it’s not as easy to drop a cold $1,000 on a fun bike. Other good news I gotta great deal on a 99’ ZR7 that I bought in May and I’ve been very happy with. Actually took a nice trip to Norway which was amazing.

still plan on doing the GS, only time will tell

[jibledso]

So real quick,

I’m considering buying a 81’ GSX 750 for the motor and putting it in my 77’ GS750.

Is this easy to do? Eventually I want to rebuild the top-end on the 77’ 8v but it’s going to cost $1,000 here in Sweden. There’s a whole bike running motor for $500. I prefer the 8v but throwing in a 16v sounds appealing after four years of not having a running GS. I know it’s not a huge difference in price but having a 6 month old son and being the bread winner cutting grass the margins are small.

[jibledso]

https://www.blocket.se/vi/91793825.htm

[Rich82GS750TZ]

May be possible, but certainly not an easy task. Engine mounting completely different. Sprocket offset may be different, not sure. the 16v engine may also be taller and may not actually fit in the '77 frame. Take careful measurement or wait to see if someone who's actually done this chimes in. If the GSX750 is a runner, why not fix it up?

Edit:
Sorry just figured out how to read the ad you posted in English. I understand now the the 81 GSX750 frame is a mess and beyond fixing with any reasonable effort.

[rphillips]

Knowing the 16V GS1100 eng. & the GS750 16V both bolt right in to a GS1000 8V frame, I'd think the GS750 8V frame would also be the same. Beware, that's only an opinion. but "I DO NOT KNOW FOR SURE.

[jibledso]

Thanks guys, it looks like it’s just too far out of the way to go get the motor. I’m on the west coast and it’s on the East. I’ll probably end up waiting till after the new year, buy some weisco pistons, bore the cylinders, and have the head redone. I’ve had the cylinders inspected and the cylinders are too far different to hone and only get new rings.