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Discussion Starter #1
Hello Chaps,
My Vigour has a probelm with the oil overheating, result rebore, new camshaft, followers and rockers along with seals etc. The problem is I can't find out why the oil is overheating, it is getting so hot that after a few miles I can't get the dipstick out. The engine runs sweetly since the rebuild, the bottom end is ok and I use Halfords 10W40. Anyone got any ideas before I start to take out the oil pump?
 

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What is making you suspect that the oil is overheating?
I would think that the oil would have to be seriously overheated/neglected to cause engine damage.

I suppose things that would make an oil overhead are the same as those that make the engine overheat such as running too lean incorrect ignition timing etc.

Phil
 

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I hate to ask the obvious but are you measuring the oil level correctly and keeping it topped up?

I'm surprised the oil pump wasn't damaged when you originally had the problem if there was so much damage to the engine. With all those metal filings in the motor, some usually manages to find its way into the pump rotor.
 

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Discussion Starter #4
Hello Chaps,
Thanks for the responses. I think the oil is overheating because;
1) When cold the engine runs fine, after a few minutes it won't idle properly, either too fast or too slow. This is apparently caused by back pressure in the oil system scrambling the carbs brain.
2) After a few minutes running I can't get the dipstick out, either due to overpressure or overheating.
3) It starts to smell of very hot oil.
4) The oil tank is very hot to touch.

My next investigation will to be to remove the oil return line and run it into a bucket to see if enough oil is returning to the tank, after that I will remove and check the strainer in the crankcase and check the oil pump.

I will keep you posted.
 

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Bloody furriner
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4) The oil tank is very hot to touch.
Mind you, this doesn't sound unreasonable, given that your average 10W40 oil likes it best at around 80 degrees celsius, and the dommie is well known for being a bit of a hothead.

I'm happy if I can keep the oil temp below 100, and that's certainly not something you'd want to touch with bare hands.

You might want to get one of these:

(I know Gericke has 'em. Nice bit of kit. Mind the difference between RD02 and RD08.)
 

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Bloody furriner
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1) When cold the engine runs fine, after a few minutes it won't idle properly, either too fast or too slow. This is apparently caused by back pressure in the oil system scrambling the carbs brain.
I'm tempted to call that last bit rubbish, as oil and fuel are completely separate systems.

What are you doing with the choke? Does it need a lot of choke to start, or not at all? Does it move freely, and does it go all the way back in?

If it runs fine when cold (assumed, with choke) and gets messy when hot (choke closed), I'm thinking it might not close all the way, causing it to run way too rich when hot.
 

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I think the others are right, the diagnosis of too high oil temperature is wrong or at least premature. I wouldn't disconnect the return line if I were you either as you'll run low on oil real quick and I can't see what it will tell you.
One quick thing to try (apart from Rubberchicken's sensible choke suggestion) is to check the crankcase ventilation hose (beneath carb). make sure it's not blocked and is venting properly - if not it can pressurise the oil tank and crankcase and cause strange running. The quick way is just remove the hose from the crancase connection temporarily and see if it runs OK.

If you've had a rebore etc you obviously need to find the real reason for the problem so it doesn't happen again - I guess it's possible the pump isn't getting enough oil to the top end, but the most common cause is not keeping the oil topped up.

Simon
 

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Discussion Starter #9
Hello Chaps,

Thanks for the feedback, the original diagnosis came from Honda mechanics, I took it to the shop because it wouldn't idle and was becoming harder to start, their immediate diagnosis was either the bottom end was nackered or it needed a rebore, this can, apparantly, cause back presure in the oil system which in turn affets the idling/running. Anyway once opened up the camshaft was goosed, the cam followers were goosed and a rebore was required. Initial wear probably down to a lack of oil.
Since rebuilding it it now runs quietly except it has started to act up when idling again, I have checked the oil pump, it is brand new and still well within tolerance, the sump strainer was clear and all of the pipes are clear. Oil is returning to the tank in quite a quantity.
I am at a loss, once the new gasket arrives I will give it another run to see if the fairies have sorted it.
I could always take it back to the shop to let them have a look but I hate admitting defeat.
 

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Discussion Starter #11
Hello Simon,

I checked the tube to see if there was any dirt, oil or water in it but it was as clean as a whistle, I have just got joints, selas etc. today so I'll out the crankcase back together tomorrow and have a go. I'll keep you posted.
 

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Discussion Starter #13
Good Evening Men,

Right, everything put back together and after 10 miles of fairly gentle running the idle revs start to creep ever so slightly, at the same time I can't get the dipstick out to check the oil level. Took the bung out of the breather but it didn't seem to make any difference. Thorughly soaking by this time I decided to call it a day and go home.
Went to work on it this morning and the same thing happens, came home and eventually when the whole lot cools down or de-pressurises enough to get the dipstick out, checked the level. Spot on and the oil is as clean as a whistle. I did notice that the separator was quite warm however that could just be radiated heat from the engine. The idling problem is not enough to cause problems but it is annoying and I lack confidence in the lubrication system.
By the way I checked the choke and set it up according the the manual I have, it starts well.
 

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I can't get the dipstick out to check the oil level
On my '99 Dommie the dipstick was difficult to get out when the motor was hot. It's not necessarily an indication of the motor running too hot. Putting a new o-ring on it can help matters but I just used an adjustable spanner on it with a cloth to prevent any marks.
 

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mine is running very similar especially today friday being very humid kept stalling all the time it runs very lumpy and plenty of vibes enough vibes i have took the fairing off sick of the rattling and now can see the road better and seems less cumbersome i prefer it without the plastic crap nowt to do with the hot tempremental idling though.
mine probs needs the carb sorting would like a makuni in there ...better??
 
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