Author Topic: castrol gtx vs gn4  (Read 10467 times)

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Offline bikerbart

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castrol gtx vs gn4
« on: June 22, 2009, 10:36:56 AM »
So,I am taking a 2500 mile ride on my old cb750 with original motor and seals.Question is,should I give it an oil change using good ol castrol gtx or Honda gn4?If I have to top off along the trip its probably easier to go with the gtx,but reputable mechanics have told me to use honda gn4.I could get Castrol anywhere but not the Gn4.any opinions?Oh and she runs great but has the usual head weepage.
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Offline Inigo Montoya

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Re: castrol gtx vs gn4
« Reply #1 on: June 22, 2009, 10:38:59 AM »
Stick with what you use now. Worst thing to do is change oil brands right before a road trip.

Offline Jerry Rxman Griffin aka MuthaF'er

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Re: castrol gtx vs gn4
« Reply #2 on: June 22, 2009, 01:49:29 PM »
+1  Don't ask for surprises.
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline tlbranth

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Re: castrol gtx vs gn4
« Reply #3 on: June 22, 2009, 02:12:41 PM »
I'm using regular car motor oil in mine just like I did in the 70's. No clutch slippage and apparently no adverse effects. I think you should stick with what you're using too. Leave the designer motor oil for the yuppies
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Offline mkramer1121

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Re: castrol gtx vs gn4
« Reply #4 on: June 22, 2009, 02:29:57 PM »
I'm using regular car motor oil in mine just like I did in the 70's. No clutch slippage and apparently no adverse effects. I think you should stick with what you're using too. Leave the designer motor oil for the yuppies

Car motor oil changed in the early '90's where they removed the additives that are required for our wet clutches.  Castrol makes a decent motorcycle oil that you should be able to find at most car places (Castrol 4T), and I'm sue a Honda dealer really wouldn't be too far out of your way for some GN4...Just carry a quart w/ you just in case at all times...

Offline MCRider

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Re: castrol gtx vs gn4
« Reply #5 on: June 22, 2009, 02:46:29 PM »
I'm using regular car motor oil in mine just like I did in the 70's. No clutch slippage and apparently no adverse effects. I think you should stick with what you're using too. Leave the designer motor oil for the yuppies

Car motor oil changed in the early '90's where they removed the additives that are required for our wet clutches.  Castrol makes a decent motorcycle oil that you should be able to find at most car places (Castrol 4T), and I'm sue a Honda dealer really wouldn't be too far out of your way for some GN4...Just carry a quart w/ you just in case at all times...
Yes the "designer" oil would have to be the late model car oil. Honda GN4 is the old fashioned dino sludge.

That's not to say the new car oil won't work. Just keeping it real.
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Offline kpier883

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Re: castrol gtx vs gn4
« Reply #6 on: June 22, 2009, 04:38:14 PM »
My 750 uses a pretty good bit of oil.  On a long trip, as you pointed out, being able to get the kind of oil you are using is important.  I switched from GN4 for that very reason.  In my case I am using Chevron Delo 400.  It is available at most any auto parts store, but it is not available at very many gas stations.  I have had some luck at truck stops, but it is often found in gallon cans rather than quarts in those kinds of places. 

On a trip when I was running GN4, I had to mix what I could find on the road with what was in the motor as needed.  I am using about one quart every 500 miles.

I plan to change my output shaft seal before taking another long trip to see if that will cut down on consumption.  The motor doesn't smoke or foul plugs, so I don't think it is burning the oil.  Funny thing is, at rest it doesn't leave over a couple of drops on the floor between rides.  It must be pouring out when in motion though.  I need to find the discussion on changing the seal without breaking the case apart first...
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Re: castrol gtx vs gn4
« Reply #7 on: June 22, 2009, 08:38:28 PM »
Use Shell Rotella 15W40.  Or any good name brand diesel engine oil is the best thing other than motorcycle specific oil because of the shear involved with the transmission gears. Diesel engine oil has lots of soot dispersents and detergents to keep your clutch plates clean and generally is way tougher oil than any regular car oil. Plus it can be had at any truck stop along the way and is cheap to boot. I have used it for 30+ years and have yet to have any engine trouble with it at all...

Offline WFO

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Re: castrol gtx vs gn4
« Reply #8 on: June 22, 2009, 08:45:00 PM »
castrol gtx is just fine.
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Offline andy750

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Re: castrol gtx vs gn4
« Reply #9 on: June 22, 2009, 09:09:27 PM »
Any car oil (mineral) will do. On my long trips I picked any oil that was at the gas station...Shell, Chevron, Penzoil. Castrol...etc etc...no problems (ha engine open since then. When at home I use Valvoline motorcycle oil (since its there) or GTX or Rotella....in other words dont worry about it.

Kpier: Using 500 miles/quart means you have problems!!! I had the same issue on an ex-bike- CB750F2. Used a quart/500 miles - was ok as long as kept topping the oil up. When i sold it, I told the new owner to do the same.....well he forgot and the engine siezed....never found out the EXACT problem but something valve related.

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« Last Edit: June 22, 2009, 09:12:14 PM by andy750 »
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Offline bender01

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Re: castrol gtx vs gn4
« Reply #10 on: June 22, 2009, 09:35:35 PM »
Honda motorcycle= Honda gn4. Thats what I use and I would think Honda would be looking out for our bikes too. Ive used others but it just seems right to use gn4. Topping off with another correct oil should be fine. If you dont forget. But at your rate of loss day 4 would have different new oil in it.
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Offline Inigo Montoya

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Re: castrol gtx vs gn4
« Reply #11 on: June 23, 2009, 06:16:14 AM »
guys, he was asking about switching to a different oil before a trip, not what brand he should be using. Common practice would be to stay with what he is using to avoid and oil related issues. Once he gets back, he can always see about changing to something else.

Offline Gordon

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Re: castrol gtx vs gn4
« Reply #12 on: June 23, 2009, 06:29:12 AM »
guys, he was asking about switching to a different oil before a trip, not what brand he should be using.

Doesn't matter.  Any mention of a question concerning motor oil for motorcycles ALWAYS spawns a new "oil thread", because there's never any shortage of people who are just waiting to give their unsupported opinion on what oil is best.   

Offline BobbyR

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Re: castrol gtx vs gn4
« Reply #13 on: June 23, 2009, 06:45:12 AM »
I think Andy our long distance traveler has give some sage advice.Top off with what you can get. Any decent sized town has an Autozone or other auto parts chain, so chances are you can be consistant with whatever oil you use. Speaking of chans, you may want to give that spritz from time to tiime.
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Offline medic09

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Re: castrol gtx vs gn4
« Reply #14 on: June 23, 2009, 07:46:46 AM »
guys, he was asking about switching to a different oil before a trip, not what brand he should be using.

Doesn't matter.  Any mention of a question concerning motor oil for motorcycles ALWAYS spawns a new "oil thread", because there's never any shortage of people who are just waiting to give their unsupported opinion on what oil is best.   

+1.  I think we need to start adding some dispute over filters, while we're at it.  I use the Honda OEM.

Greetings from Estes Park, btw.  Used most of Jerry's directions for the extended ride up.  The ride through Wolf Creek Pass was just about the prettiest ride I've been on so far.  The hairpins kept me from gawking too much, though.  The ride north from I-70 up 119-72-7 was great, too.  Chronic neck injury means I may be stuck recovering with some fishing today.  Trail Ridge Road tomorrow, maybe.  Lots of great looking granite here, for you climbers.  My wife doesn't climb anymore, so didn't bring any gear.

Anyway, like I was sayin, I use GN4 and an OEM filter.  Wanna fight about it?   ;D
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Offline Gordon

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Re: castrol gtx vs gn4
« Reply #15 on: June 23, 2009, 08:04:58 AM »
Greetings from Estes Park, btw.  Used most of Jerry's directions for the extended ride up.  The ride through Wolf Creek Pass was just about the prettiest ride I've been on so far.  The hairpins kept me from gawking too much, though.  The ride north from I-70 up 119-72-7 was great, too.  Chronic neck injury means I may be stuck recovering with some fishing today.  Trail Ridge Road tomorrow, maybe.  Lots of great looking granite here, for you climbers.  My wife doesn't climb anymore, so didn't bring any gear.

Nice! :)  I just did the peak-to-peak ride up to Estes on Sunday for my Father's day ride.  Trail ridge road can be a really nice ride if you catch it on one of the rare days that it doesn't rain.  Hopefully that will be the case for you tomorrow.  Last time I went we got caught in a huge thunderstorm and just made it inside the visitor's center before the hail started.

Offline JBMorse

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Re: castrol gtx vs gn4
« Reply #16 on: June 23, 2009, 08:15:19 AM »
I'm surprised nobody knew this, but Hondas run vegetable oil!  




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Offline Inigo Montoya

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Re: castrol gtx vs gn4
« Reply #17 on: June 23, 2009, 08:50:09 AM »
being able to pick oil on the trip is one thing. I say to stick with the same oil to minimize potential problems. Different oils have different additive packages. Think about how fast a trip would end if you switched oil and then you got clutch issues or something else not fixable on the road. At least keeping the same oil if possible can help lower those chances.

Offline bikerbart

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Re: castrol gtx vs gn4
« Reply #18 on: June 23, 2009, 08:58:50 AM »
thanks guys(and gals?)I have done everything I can think of,valve adjust,carb sync,oil,plugs,new dyna s and coils,Fresh airbox rubber and filter,tires,chain,I will stick with the GTX,last time I switched to a fancy oil I got clutch slip,Maybe after I put new gaskets and rings I will try Honda GN4,I am riding from Bellingham Wa(think Canada)to Laguna-Seca moto Gp,going to do the coast the whole way as long as the weather holds out,camping the whole time.My buddy is riding his ducati 848(pain)I will be a LOT more comfortable.
its better to regret something you have done,than something you havent.Except playing with explosives.

Offline WFO

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Re: castrol gtx vs gn4
« Reply #19 on: June 23, 2009, 12:02:43 PM »
I'm surprised nobody knew this, but Hondas run vegetable oil!  






I saw that episode and that cub is one tough SOB.
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Offline andy750

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Re: castrol gtx vs gn4
« Reply #20 on: June 23, 2009, 04:11:16 PM »
being able to pick oil on the trip is one thing. I say to stick with the same oil to minimize potential problems. Different oils have different additive packages. Think about how fast a trip would end if you switched oil and then you got clutch issues or something else not fixable on the road. At least keeping the same oil if possible can help lower those chances.

Sorry but this is BS....read my earlier posts...I have used all kinds of standard car oil - whatever cheap crappy oil I could get- on all my long distance trips (~35,000 miles worth of riding). Regular oil dosent cause you problems. If you change to synthetic then yes it might but not regular oil.

Have you ever had this experience and could say it was the oil for sure? A trip is not going to end because you cant find your expensive Honda GN4 oil  ;D Your trip will end if you dont have a well maintained bike or you get a puncture (and this is easily fixed). ..I have never had a bike trip end...only delayed till I could fix the problem...and with these older bikes it is easier to fix by the side of the road.....

cheers
Andy

Current bikes
1. CB750K4: Long distance bike, 17 countries and counting...2001 - Trans-USA-Mexico, 2003 - European Tour, 2004 - SOHC Easy Rider Trip , 2008 - Adirondack Tour 2-up , 2013 - Tail of the Dragon Tour , 2017: 836 kit install and bottom end rebuild. And rebirth: http://forums.sohc4.net/index.php/topic,173213.msg2029836.html#msg2029836
2. CB750/810cc K2  - road racer with JMR worked head 71 hp
3. Yamaha Tenere T700 2022

Where did you go on your bike today? - http://forums.sohc4.net/index.php?topic=45183.2350

Decapitated Toy

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Re: castrol gtx vs gn4
« Reply #21 on: June 24, 2009, 05:17:43 AM »
greetings from burlington, wa.....im in bellingham once a week or so. i take it you will be taking the 1??  i agree that sticking with what you use already is the best course.

Offline Inigo Montoya

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Re: castrol gtx vs gn4
« Reply #22 on: June 24, 2009, 07:51:13 AM »
Actually andy, yes, yes I have experienced this. Not my vehicle but I was with when it happened. If you use the same oil a long time, your engine can get conditioned to that additive package. A couple hundred miles later, after using a different oil, his oil return lines had plugged up and then oil pressure built up and blew out the lines. What happened? The old oil left some sludge behind(it was conventional after all) then new oil cleaned it off and this sludge clogged up the filter and then the return lines. This truck had a remote mounted oil filter. Of course it MAY have still been coincidence but the truck was taken to a reputable shop, NOT a dealer shop, but one that had been around for over 30 years and is still around. So there was a VERY good chance the different oil caused this.

Now if you are constantly using different oils like you, this is probably not an issue. What do you think though if you were on a road trip and sludge broke loose and clogged an oil line in the head? Not exactly a roadside repair now is it. I am not telling him to never change to a different oil, just to wait till after his trip to help minimize POTENTIAL issues. You do not have to agree but you also do not have to be a dik about it.

Offline Duke McDukiedook

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Re: castrol gtx vs gn4
« Reply #23 on: June 24, 2009, 08:00:29 AM »
I always thought Wolf Creek pass on the west side would be interesting on my bike.
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Offline Inigo Montoya

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Re: castrol gtx vs gn4
« Reply #24 on: June 24, 2009, 08:25:51 AM »
I want to hit glacier national and Yosemite sometime.