Need to do an oil change shortly and would welcome any suggestions as to the best type to use i.e. synthetic/semi etc, viscosity and brand. UK based and currently road use only; apart from last night when I became a little agitated with the traffic in Norwich and decided to ride home cross country totally illegally - but was great fun all the same. Apologies to any farmers who may be viewing. Cheers Bob

anything you like, mate. I've been all over africa, australia, russia and the middle east on them. I've had to use oil for diesel engines, SAE 40, 20W50, 0W50 synthetic. I also used 80 octane rubbish and the worst effect has been a bit of smoke. no pinking, just black smoke and a bit of glaze in the carb.

together with two mates, we've done 120-150,000km on BRPs and they're tougher than all of us ... one of them got water in his enigne, changed the oil and set off across australia.

let me know if you manage to blow yours up or wear it out cos honda built 'em to outlast all of us

I have had some problems with clutch slippage when using synthetics. As in, the bike would lurch forward with the clutch lever pulled in and switching into first gear.

The clutch system is lubricated by the same oil the engine uses and seems to not care for the synthetics. I would recommend sticking with standard 4 stroke oil.

I have heard from tons of other people who have had no problem using synthetics, but from my experience, its a bad idea.

The source of the problem you described must be something else, like clutch cable maladjustment or warped clutch plates, which can all be a source of a clutch dragging when you switch into first gear and engage the clutch. The increased slipperiness due to the friction modifiers used in synthetic oil could indeed be a possible source of clutch slippage but only under load and thus with the clutch engaged, not with the clutch disengaged as you mention.

If the bike starts moving forward when the clutch is disengaged and is in gear, that means there is excessive friction between the friction and pressure plates in the clutch. The clutch plates are not completely disengaged, and thus 'drag' each other along. Your argument doesn't hold, as the friction modifiers contained in synthetic oil reduce friction compared to mineral oils with similar viscosity. So if the bike lurches forward when kicked into gear, the 'clutch drag' problem should be even worse when using mineral oil. The 'clutch drag' problem that your bike suffered from is in fact the opposite of the problem you referred to with respect to the use of synthetic oils. The problem of clutch slippage when using synthetic oil usually occurs when the engine is working under full load, so at high revs and/or under full acceleration.

This said, forget about semi-synthetic oils, it's the biggest marketing scam in the lubrication business. Either spend more on fully synthetic oil or save your money and buy a good quality mineral oil and change oil more often. All my thumpers run on fully synthetic oil and I never had a problem with clutch slippage with any of them(*), even racing enduro's in the tropics or adverse travelling conditions (high temperatures in Africa and Asia). But that's only my experience, some might have experienced otherwise.

(*)Currently own 13 bikes. Apart from my XR650R, my four KTM EXC's (2x450, 520, 525), KLR650, BMW F650, and two XT350's all run on synthetic without any clutch slippage.

Forgive me for hijacking this thread as my question is off topic, but I'd like to ask RichLees if he reinforced or even replaced the XR650R's notoriously weak subframe with a custom-made stronger frame (made of steel?) in order to carry luggage on his long journeys. I've ridden my XRR up and down the entire length of the Baja, but without carrying any luggage to speak of, only a lightweight sleeping bag and pad. I'd like to take my XRR on a longer trip but the OE subframe can't carry any weight. Any suggestions?

Thats all very technical and thanks for your reply... but it was definitely the synthetic oil causing the problem.

When I opened up the clutch housing a super sticky mess had been created in there by the synthetic oil. It took a long time to clean out and get working again. And after cleaning all the old oil off the parts... low and behold, a perfect shifting bike.

Thanks for your technical response, but I stick to the statement that synthetic oil with mess up your clutch.

Stay away from it.

Hi Rich, hows it going?
Im in the process of changing my NX650 oil pretty soon! As usual due to financial crisis Im looking for cheapest but good oil. Since you mention it... looks like I might just use Castrol GTX its the cheapest on the market!
I also found a Moped (4stroke 110cc) oil filters that is not only fits but INDENTICAL to the NX!! Should I use this filter?:confused1:

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on the ozzie and africa trip, I had rear tanks with 13 litres of fuel on the right and 11 litres of water on the left. the exhaust was routed under the right tank and the tent slung under the left. the rear tank rack was mofo heavy but connected to the footrests and a long stud where the subframe is usually bolted to the frame. the steel min-sub-frame was also reinforced. all in all, the aluminium subframe was kind of bypassed and gave no grief despite having 12kg of luggage on the tail piece and another 7kg on a front rack.

on the middle east/asia trip, I had a 15-17kg kit bag on the back without having reinforced the rear subframe, but I rode like a jessie and stuck to tar (I'd cracked a vertebra in June and was chicken about hurting it again)

GTX is fine for the way most of us ride most of the time. I'd rather replace reasonable oil regularly than leave good stuff in forever

happy travels! may your oil checks be regular and your changes be free from shiney metallic bits

when do we get to see some pict of your trips, you have to learn to share .

Thanx for the advice, what about the filters, should I used the 4 stroke 100cc postie bike filter for my Dommie? Its very indentical!!

I just had new sleeves/piston..... am I supposed to find those metallic bits? What happen if its there?

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I agree with your point that semi or synthetics should ease the problem of a dragging clutch rather than worsen it.

Why do you say that semisynthetics are a scam? You may be right but what's your evidence?

Heard about clutch slippage due to synthetic oil before... but not sure if its true.

Lots of my riding buddys were using "MOBIL 1" when it was first introduce here (in the mid 90's in think) mostly sportsbike though. They also had the same problemo! eversince that I always have the impression to stay away from them.

like Rich said: use the reasonable ones & change it regularly than keeping the good ones...
btw Rich whats the measurement for the oil? 3litre right? its not in the manual...

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From memory without looking at the manual, (mine sure does have oil capacity in the manual) the XR650 takes 2 litres of oil in total from new or when rebiult, but when changing the oil and filter its about 1.7 litres but you won't get 1.7 litres in in one go without getting it kicked over or running to circulate it a bit.

Although it seems strange, it is a fact that some engines (mostly hondas) have a clutch problem with synthetic oil.
Synthetic oils "stick" better to surfaces, that is part of their good characteristics.... except when the space between clutch-plates is very very narrow. The oil-film that "sticks" to the clutch-plates is causes the plates to be "sucked" together.
This causes a "sticky" clutch, difficult and noisy gear-shifting and a problem getting it in neutral.

The same effect can occur when you use oil that is to "thick" (wrong viscosity).

If this problem occurs, just "stick" to mineral oil

Happy miles,
Maarten

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I have synthetic in my bike at the moment and i have heard that if you change back to mineral the oil will sludge, is this true and if so how can i get around that.

thanks guys