Yamaha TRX850 Enthusiasts Forum

just checked mine and while they are in spec its only just , so i was thinking of new ones there's a bit of scoring inside but not bad and i get a tip clearance of .10,,, std is 0 to .12,,, with a limit of .17,,, engine buffs i need your input please

Hard to say... Don't think it's necessary, but if you have the cash, why not? Good oil pressure is kind of vital... I changed pumps, and now I sleep much better

If it's within recommended limits then don't worry about it....

thanks HansJ,, this is what i think,, if the oil pumps are a bit out of spec and for all i know it may have been like that for a while and i am now putting the engine under more stress, ie , fcr41s, big bore exhausts its being bored out to 878 as we speak , ive done the cam chain,, ive done the head valve stem seals lapped in the valves a touch they didn't need much,, why not replace the oil pumps, they are £200 not cheap i know but cheaper than a new crankshaft ,,the bottom end is in very good nick with no play anywere that i can find , ive also cleaned out the sump strainer there was a few small alloy particals in there but not much ,,,,so balls to it new pumps it is

steve speed wrote:thanks HansJ,, this is what i think,, if the oil pumps are a bit out of spec and for all i know it may have been like that for a while and i am now putting the engine under more stress, ie , fcr41s, big bore exhausts its being bored out to 878 as we speak , ive done the cam chain,, ive done the head valve stem seals lapped in the valves a touch they didn't need much,, why not replace the oil pumps, they are £200 not cheap i know but cheaper than a new crankshaft ,,the bottom end is in very good nick with no play anywere that i can find , ive also cleaned out the sump strainer there was a few small alloy particals in there but not much ,,,,so balls to it new pumps it is

Bollox (No offence....) It would still pump oil if it was out of recommended limits (Recommended service limits are always very conservative anyway) Up you at the end of the day though....

i know what your saying but i would be really pissed if it went wrong because i didn't fit new pumps , at least this way i have done all i can to keep the motor in good order,,,its only beer money

steve speed wrote:i know what your saying but i would be really pissed if it went wrong because i didn't fit new pumps , at least this way i have done all i can to keep the motor in good order,,,its only beer money

I understand where you're coming from but.... How're you gonna feel when your 'new' pumps measure the same (or worse) than the old ones? If the clearance tolerance is 0-0.1mm there's every chance a new one wont be any better.... £200 buy's a lot of super plus!

one of the reasons is that when i rev the bike the oil window empties, and i would have thought that because the return pump is bigger this would not happen it is as though the return pump cant keep up ???

I don't think that's a sign of worn pumps, I'd guessed all TRXs would behave the same (but I am not sure though)

I agree fully with Honk, Your pumps will prolly work fine. Mine would have too. Spending 200 is just like paying an extra insurance. If You don't have the cash, it's a steep investment. But there are many other investments in our beloved TRXs that are hard to justify, depending on who You talk to Each to his own.

I changed the camchain, although it was in spec, I had the money, the time, and now I don't need to worry. Each to his own...

thanks for all your input guys ,,you probably right and new pumps are not necessary ,, i do intend on keeping this bike for quite some time and i have just got a 25% discount on the new pumps so i will be fitting them , thanks for all your help

Hang on to the old pumps, you never know when some poor relation on here may need them.

Dave E

new ones arrived today and when i checked them they are at the tight side of the spec,, tip clearance .03 and the outer rotor clearance of.04 so it looks like a bit more oil pressure and a bit more return ,,,,all good not pigin cheap though