GS750EX 81 to 83 GS750ES Engine

[koolaid_kid]

Has anyone took a 1981 GS750EX engine and installed it in a 83 GS750ES Frame? Thanks Tom Would it fit with modifications? Thanks Tom

922toms, are you aware that the 83 750s were a new, updated design? This is why going backwards would not be an ideal answer. Most likely they also changed the frame, mounting points, etc.

not even close to a bolt in.
a GSXR engine would be better suited.

922toms, this is a real, unbiased answer. The new design carried on for several years, at least 86 & perhaps even 87. An air/oil cooled GSXR engine would be even better if it is an easy bolt-in.

 

[Larry D]

As you can see in my signature, I too, have this engine. And, I too, absolutely love it !!! My bike screams and is a blast to ride !!!

However, the '80-'82 750's have top-end oiling problems. Not only does the oil pump need shimmed, the internal oiling passages themselves are designed differently from the previous and latter 750's

I changed the oil regularly and kept in running in tip-top shape, as several members here can attest to, however, this still happened. I have no doubt that you have years of experience with motorcycles, but, there are several members here that know EXACTLY what they are talking about. Here's some photographic evidence for you.

 

[xjandgs]

"And now, for something completely different..."

I like you already

 

[xjandgs]

As you can see in my signature, I too, have this engine. And, I too, absolutely love it !!! My bike screams and is a blast to ride !!!

However, the '80-'82 750's have top-end oiling problems. Not only does the oil pump need shimmed, the internal oiling passages themselves are designed differently from the previous and latter 750's

I changed the oil regularly and kept in running in tip-top shape, as several members here can attest to, however, this still happened. I have no doubt that you have years of experience with motorcycles, but, there are several members here that know EXACTLY what they are talking about. Here's some photographic evidence for you.

Thank you for a nice email with a nice offering of friendly information. That I appreciate,

It's amazing how a tone and offering of friendly advice feels so different than somebody trying to force feed you... Much appreciated.

 

[Larry D]

No problem. I don't think it was any more or less friendly than the anyone else's posts.......but, keep in mind, the typed word is often not how it would come across in person, all the inflection and emphasis sometimes seems misplaced when sentences are typed.

There are alot of very, very helpful and knowledgable folks here who are willing to share their experiences.

 

[Nessism]

It's a FACT that air cooled GS engines can run HOT. They can run VERY hot in fact when stuck in traffic where there is very little air flowing over the engine. My bike, which has an oil temperature gauge, routinely runs over 300F, and I've seen as hot as 330F. We have had a number of posts here where members have commented about getting stuck in traffic on a hot day and their engines started to spew out lots of white/blue exhaust smoke. I believe in these instances their oil was flashing off into vapor which is a very undesirable condition.

It's a FACT that synthetic oil has a higher flash point and is more viscosity stable at high temperatures. This means that it will protect your engine better than mineral oil in those EXTREME instances - such as getting stuck in bumper to bumper traffic with the air temp over 90F. Does this mean that you need synthetic oil? Of course not. My belief though is that synthetic oil is a reasonable risk mitigation method just in case, which is why I use it and recommend it.

It's a FACT that the 2nd generation GS750 engine has oiling system problems. Suzuki promoted a dealership fix to shim the oil pressure relief spring to help mitigate this risk. Does this mean that all 2nd gen GS750 engines are going to fail? Of course not, but dismissing this history is just plain dumb.

I don't think there is a significant connection between synthetic oil and CAFE (fuel economy), although that may be where the thought began. If CAFE were a prime driver for use of synthetic oil, then more OEM auto companies would spec the stuff, but they don't. The OEM's are using THINNER oil these days, presumably to save gas, but there isn't a whole lot of synthetic oil being used as far as I know. In the automotive world the primary driver behind using synthetic oil is extended drain intervals. BMW has a free maintenance program, and they spec synthetic oil because it extends the drain interval to 10,000 miles, thus they save money. For car owners that maintain their vehicles decently and don't care about extending their change interval, then synthetic oil provides no real benefits. But don't confuse this with no benefit on an air cooled motorcycle.

Oh, and I worked in the engineering department of a major OEM automotive company for 21 years, so I have a little background that helped form my views on these matters. I've seen a LOT of oil related engine failures in my day, which helped form my views on oil.

Some may think my personal style is abrasive at times, and they would be right, but the fact remains that what I say (most of the time) is technically correct. I'm not here to hold everyone's hand and pat them on the back, but I do try to dispense with useful information from time to time.

 

[xjandgs]

Let's all FORGET about the oil debate being raised by Mr. Narcissism --- I mean Nessim (sorry Ness - I could not resist that play with words)...​

The entire string was started when somebody asked if a 81 GS 750 engine would fit into an 83 frame (presumbably b/c he has his eye on that engine). He did not ask if the engine was good or bad. Somebody offered it was "AN AWFUL ENGINE." Then Nessim got involved. I chimed in a counter view (as I have the 82 version of this 16 valve engine) that it was a great engine - and from that I have Nessim telling me about all of its problems which are good and well, but telling me I am essentially negligble for not using synthetic oil and on and on.​

And I quote - from this very own webiste in pertinent part as follows (when this site describes in its section - the History of the GS Engine:​

"...The 2-valve-per-cylinder-powered bikes are recognized by experts as the most reliable, bulletproof engines the world has ever seen, closely followed by the air-cooled 4-valve-per-cylinder-GS's.​

These classic engines have True Grit: no matter what happens, they will take you home."


Why is the GS engine so utterly bullet-proof?


Basically, there are three aspects that set the GS engine apart from its contemporaries:

​

• The first is the fact that the crankshaft runs in roller bearings, which is quite complex (and expensive) to build, and which caters for a long engine life and for high resistance to uneven or higher load on the crankshaft. (Note: this goes for most models, but the GS450 engines are a noted exception, they aren't blessed with roller bearings)
• The second is that the lubrication is basically designed as a low-pressure job, which does not suffer as much from poor​

• pressure, cold engine oil and clogged channels.​

• 
  
  [*]The third is that, contrary to contemporary habits, there is a lot of reserve built into the design. The market demand for space and weight saving was not as large as it is in these FireBlade and GSXR750W days, and so the engineers of these bikes didn't have to drill iron out of the design to make the bikes marketable...
  

So did I pass misinformation on to this intial person defending this engine. If I did as is implied by Ness... then so isn't this entire website by that existing article/page.

Which is it - I ask. Is this not the "followed very closely by the 16 valve engine" to the 8 valve as being bullet proof or is it a disaster waiting to happen as Ness would have us believe?​

 

[Nessism]

So did I pass misinformation on to this intial person defending this engine.

The 2nd gen 750 has a PLAIN bearing crank. NOT roller bearing
The 2nd gen 750 engine has a HIGH pressure oiling system, NOT low pressure like the roller bearing engines
The 2nd gen 750 engine is the worst of all GS engines when it comes to durability.

Your engine was one of the first Suzuki designed with plain bearings, and frankly they screwed up the design of the oiling system.

I don't care if you want to ignore this fact, but my suggestion to people that do care about reducing the risk of engine failure is 1) shim the pressure relief spring, 2) use either diesel or motorcycle grade synthetic oil

 

[xjandgs]

Geez:

Maybe you should have the website's engine history updated b/c it sounds like per your investigative research and experience there should be one big old asterisk with it.

Any engine is capable of failure - plain and simple - my initial response had little to do with you but more in response to the first person who said it is a "bad engine." I said it is not and stand by that. The 1980-82 engine is a solid engine. Let's stay on point and not get side tracked with you and your synthetic oil... I could care less that you think I should use synthetic... Tell somebody that cares.

This website claims it is a solid engine as you can see from what I quoted below in my earlier post ...

So if you want to dispute my claim on this engine being good, you may also want to talk to the author of that article or the person responsible for this webpage and let him or her know there is a blatant error in his article so you can save the vast majority of us rather than a few here reading this post....:lol:

 

[koolaid_kid]

Would it be possible to stop all the bickering and get back on topic? Please?
The OP wanted to know if the engine would fit.
Blowerbike said it would take a lot, lot of work, and that a later model engine would be a much better choice. Rapidray said with enough money anything could be made to fit.
I really think that answers the question.
922toms, do you have any other questions?

 

[rustybronco]

So my ramblings and insults were to you, for one specific reason and one reason only, because they were warranted.

No they were not and as such were reported.