Will Synthetic Oil kill my Clutch?

[Anonymous]

I just purchased(my first bike) a 1978 GS750E. It only has 32,000 miles. I need to change the oil. Cycle Gear Has recomended synthtic oil from Castrol. Although, this guy from work who has been riding older bikes, says that it will kill my clutch. Apparently it has something to do with it having an older clutch. I want to put synthetic in or a blend because of it's ablity to cool the engine and transmission. I would like to know some facts if at all possible.

Sincerely,
Chris
Portland, OR

[Anonymous]

Re: Will Synthetic Oil kill my Clutch?

I just purchased(my first bike) a 1978 GS750E. It only has 32,000 miles. I need to change the oil. Cycle Gear Has recomended synthtic oil from Castrol. Although, this guy from work who has been riding older bikes, says that it will kill my clutch. Apparently it has something to do with it having an older clutch. I want to put synthetic in or a blend because of it's ablity to cool the engine and transmission. I would like to know some facts if at all possible.

Sincerely,
Chris
Portland, OR

It wont kill anything but you will have to try it and see if your clutch slips--if it slips then the clutch will wer--i have just started using (5-50) syntec and it works fine for me--i also used mobile 1 (15-50) when i first rebuilt the top end and again no problems--the only problems that i had were when i switched to 10-40 dynasour oil after which my well worn valve guides saw fit to pass some of the lower viscosity oil when heated up--if your clutch slips, it will be my guess that it is worn to the point of needing disks and/or springs and possibly both--old bike doesnt usually mean anything its the mileage and abuse

YOU PICKED A GOOD SUBJECT AND WILL GET TONS OF OTHER OPINIONS ON THIS ONE

[brs127s]

When I got my 77 GS550, it only had 3850 miles on it. I ran it for 2 oil changes using Castrol GTX 10W-40. It seemed like it wanted to use some.
After alot of research, I switched to a synthetic oil. The bike seemed to run a bit cooler, and it stopped using oil(I think the Castrol was boiling off. Automotive oils work okay, but motorcycle oils are formulated to be used by the engine and transmission). The bike ran better, and the clutch never slipped(It was the original clutch). I had already replaced most of the seals, because they had aged(the bike sat for 15 years without running, with the exceptions of once or twice in that time frame). The seals that I had not replaced did not leak. I went with Amsoil 10W-40, even got my neighbor with a 98 1200 Bandit to use it. He liked the Amsoil, and never had a problem with it either.

[Hap Call]

I used Castrol 20W-50 for years and had no problems. When I rebuilt my bike the last time I broke it in on 20W-50 for 600 miles (it is recommended that you break in on dino oil so that the rings seat well) then switched over to Mobil 20W-50 Synthetic motorcycle oil. It was okay for about 1000 miles then the clutch started to slip. I replaced the clutch friction plates (but not the metal plates) and continued to use the Synthetic. I have not had a bit of problem with them since. It appears to me that what ever oil you start with on the clutch plates, it is best to stay with it.

Hap

[Anonymous]

Synthetic oil is a total waste of money unless your oil heats to over 310 degrees F. That's the temperature mineral oil starts to break down. If these engines had conventional main and rod bearings i'd say 270-280 degrees F, as the temp in the bearings is about 30 degrees higher than in the pan. I use Castrol GTX, I've used it in every bike i've owned since 1987. I have never had an oil related breakdown, and doubt I ever will.

Tim

[Anonymous]

Synthetic oil is a total waste of money unless your oil heats to over 310 degrees F. That's the temperature mineral oil starts to break down. If these engines had conventional main and rod bearings i'd say 270-280 degrees F, as the temp in the bearings is about 30 degrees higher than in the pan. I use Castrol GTX, I've used it in every bike i've owned since 1987. I have never had an oil related breakdown, and doubt I ever will.

Tim

most of us do not use synthetic for economy and usually change our oil way too frequently any way--a waste of mony is a point of view only--i oil my chain every 200 miles and slop the stuff on --this is also a waste of money. i dont wait till i need brakes or tires to change them. sometimes i just change oil --brakes --tires to see if i can tell the diference-i also do it with countershaft sprockets and will soon be swapping carbs and wires--- but some of us are just die hard motorcycle hobbyists and an over kill is quit common for die hard hobby types
I keep about 4 sets of spark plugs of diferent heat ranges so i can see the effect of the change on my plug colorings also

[Anonymous]

Wow, I love this place

Thanks for all the responses. The interesting thing is this. This guy that I talked to said that I would kill my clutch. It was the same tone as, "don't drink oven cleaner" type of a tone. I looked at clutches on JC Whitney, andd they are less then $100. So, if I kill it, well I guess I get a clutch. I believe, not having years of automotive experiance, that synthetic is by and far better for most motors. Although, I know that it is not the savior of anything. But, I know that my bike can get pretty hot in stop and go traffic. So bottom line. Maybe I should take it to the local bike shop and talk to them. By the way, I totally appreciate all these responses.

[jpaul]

When looking at the synthetic oils, the thing to look for the the energy saving logo on the label. The oils that have this logo contain additives which will plate out on the clutch surfaces. Normal synthetic oils work just fine. If you are in the habit of changing your oil at regular 3000 mile intervals, any good quality oil will be sufficient. If you are the type of person who procrastinates and end up changing at less frequent intervals, it may be worth the extra cost to go with a synthetic.

[Anonymous]

Re: Wow, I love this place

Thanks for all the responses. The interesting thing is this. This guy that I talked to said that I would kill my clutch. It was the same tone as, "don't drink oven cleaner" type of a tone. I looked at clutches on JC Whitney, andd they are less then $100. So, if I kill it, well I guess I get a clutch. I believe, not having years of automotive experiance, that synthetic is by and far better for most motors. Although, I know that it is not the savior of anything. But, I know that my bike can get pretty hot in stop and go traffic. So bottom line. Maybe I should take it to the local bike shop and talk to them. By the way, I totally appreciate all these responses.

i used a JC whitney clutch in my Kawa eliminator (castroll 20 -50))oil and beat the bike to death in 1/4 mile street races--it seemed as good as any other clutch

[Anonymous]

Re: Wow, I love this place

Thanks for all the responses. The interesting thing is this. This guy that I talked to said that I would kill my clutch. It was the same tone as, "don't drink oven cleaner" type of a tone. I looked at clutches on JC Whitney, andd they are less then $100. So, if I kill it, well I guess I get a clutch. I believe, not having years of automotive experiance, that synthetic is by and far better for most motors. Although, I know that it is not the savior of anything. But, I know that my bike can get pretty hot in stop and go traffic. So bottom line. Maybe I should take it to the local bike shop and talk to them. By the way, I totally appreciate all these responses.

i used a JC whitney clutch in my Kawa eliminator (castroll 20 -50))oil and beat the bike to death in 1/4 mile street races--it seemed as good as any other clutch

[Anonymous]

oil

i use nothing but amsoil synthetic designed specifically for motorcycles.
any amsoil delaer would have. no clutch slippage whatsoever!

[Anonymous]

What kind of clutch plates came original with the 78 Suzuki GS750E. Possibly, this could be the issue with the synthetic oil.

[dpep]

90,000 miles on synthetic

I ran my 80 850g from 10,000 to 100,000 miles using Mobil 1 automobile synthetic. No clutch problems, and motor was still running well on the original set of rings when I had everything rebuilt in prep for next 100,000.

The best reason to use synthetic is that it sticks better to the metal. Most engine wear occurs in the first couple of seconds after starting. Also, it does hold up better if you can't get your oil changed right when you should--a little extra insurance.

There have been changes to oil grading in the last few years that make the use of current automobile oil more in question.

DonP
80 GS850G

[Anonymous]

Which oil

It is not that the oil is synthetic or mineral it is the additives in the oil. Oil made to SG standard should be used in bikes, any higher a spec and the anti friction ingridents will make the clutch slip. Mineral, semi-synthetic or full synthetic, it's up to your wallet, just look for SG standard.
MartyC :roll:

[redliner1973]

As for the SG rating, it is perfectly safe to use any 'SL' rated oil in your bike AS LONG as it DOES NOT have 'Energy Conserving' or a 'starburst' emblem on it. you can see this on the bottle Usually the starburst is on the front and Energy Conserving, or Energy Conserving ll is on the back. these oils contain friction modifiers that may lead to clutch slippage on motorcycles. Here is the good news.....Almost all 10W-40, 20W-50, and heavier oils, including synthetics, do NOT contain these modifiers ( due to the cost, as most auto manufacturers do not reccomend these heavier oils ) and will not have these symbols on the bottle to identify with them. After alot of my own research on this subject, most 'experts' say that cluch slippage after using synthetic oils is caused from the base synthetics ingredients attacks 'varnish and sludge' on the plates, and doesn't wash it off evenly, causing less plate material to actually engage, therefore slipping occurs until all of the 'varnish' is removed. I use Synthetic on my '83 GK, after dino oil was used. I haven't had any problems with it at all. It really boils down to choice, some swear by dino's, some by synthetics. while I personally recommend synthetics, I also believe that changed regularly, any QUALITY motoer oil that you are familiar with and trust in your auto will meet your need. Hope that helps...