R65 Resurrection

[Sejati]

Have you check cylinder with compression test ? Loosing compression also means loosing power.

[Bob_Roller]

lAlight coating of oil is ormal on the intake tubes, the crankcase breather system vents into the 'horns ' in the airbox .

With the slide all the way down, is there a lot of play between the needle and needle jet, I don't think the needle will be that exposed in most riding conditions .

[Barry]

The needle are not intendeded to be rigid otherwise aligmnent with the needle jet would be super critical and if not achived cause stiction and wear.  As long as there isn't too much vertical play they are probably fine.

The thing to do while they are out is measure the length of exposed needle to confirm both carbs are set the same. There is only approx. 1.8mm diffrence between each click position.

[TomHoldom]

Hello, thanks for all the comments.

I've sorted my problem of the engine getting lumpy and bogging when accelerating.
I had been assuming that it was the right side which had a problem as that is the side running the cooler of the two.

But after doing a quick check on the idle and main jet on the left (hot) side I found a bit of crud in main jet which has resolved that issue.

However even with what feels like full power returned, the left side is still getting hotter than the right.

On a short 5 min ride flicked on water evaporates immediately on the left where as on the right it just slowly evaporates off with no sizzle and I can even lightly touch it after a minute.

Of the two, does this sound more like the right not being hot enough (misfiring?) rather than the left being too hot?

I have swapped the spark plugs and the left remains the hotter side.
I have swapped the leads (which are new) and the left remains the hotter side :-/

[TomHoldom]

One further thing I've just noticed is that the right (cooler) side runs fastest with the mix screw fully closed......

actually to be more precise, the screw position doesn't seem to changed much, until at fully seated idles significantly faster - too fast

Barry, I will check the needle lengths this week as I understand that this behavior could be a symptom of unequal needle installation.

[Sejati]

If I’m not mistaken, fully closed mix screw means rich idle setting. CMiIW.

[wilcom]

If I’m not mistaken, fully closed mix screw means rich idle setting. CMiIW.

Closed idle mixture screw would be lean.

https://www.youtube.com/watch?v=wyspAHrMbb8

[TomHoldom]

Thanks for the carb animation wilcom

I’ve checked the needle position which is correct for my 1979 flat top carbs - clip position 3 with 2.66 needle jet.

So presumably if I am able to idle with the mixture screw fully closed and choke off, this means that fuel is accessing the combustion chamber in some way that it shouldn’t…..?
Given that the idle speeds up when fully seated this feels inconsistent with a damaged tip to the mix screw, so does this only leave a faulty choke as the possible source of fuel, or at least the most likely?

[Barry]

So presumably if I am able to idle with the mixture screw fully closed and choke off, this means that fuel is accessing the combustion chamber in some way that it shouldn’t…..?
Given that the idle speeds up when fully seated this feels inconsistent with a damaged tip to the mix screw, so does this only leave a faulty choke as the possible source of fuel, or at least the most likely?

I agree it's unlikely to be the mixture screw. The choke certainly is a possibility and should be checked for correct assembly but it's more often something else like an air leak or faulty O ring.  You have to wonder how air and fuel get past a closed throttle plate and closed mixture screw but there is a path through the auxiliary air passage and transfer ports.

[TomHoldom]

Well, it looks like that carb is coming off and the choke taken apart.

I have a 30 mile each way trip to make to get to my nearest BMW dealer to get a document I need for importing, do you think that doing that sort if distance is likely to be ok - it generally feels good to ride....?

I also have a few small oil leaks some of which could be due to when the cylinders were taken apart at the beginning of this project, they were put back together without a torque wrench....

Should I try and fix first by torquing correctly, or would it more sensible to buy motobins top end gasket and seal set (2xhead gasket, 2x rocker cover gaskets, 2x barrel base o-rings, 4x pushrod tube grommits and 4x barrel stud o-rings)?

There is also a drip which forms on the drive-shaft gaiter - see last photo - it forms on the underside of the gaiter then runs down swing arm and ends up on the bevel drive oil drain plug.
Is this one I could try and simply do up the clip?

[Barry]

A trace of oil is nothing to worry about. Before the trip I would slacken off the head bolts half a turn and re-torque. If it still leaks you can address it later.  What figure are you planning to use for head torque ?  Given the propensity for threads to pull out of the crankcase I chicken out at 23ft/bs and have never had leaks or any other problem. Definitely don't go above 25ft/lbs.  I would also re-use a nearly new head gasket and have never replaced a rocker cover gasket in 14 years because they don't leak a drop

If you are buying parts you might want to get a new speedo drive rubber to keep water out of the gearbox.

[TomHoldom]

I was going to use my HAYNES manual 3 stage process - 11, then 26, then 29,5 lbf ft (models upto 1980), but by the sounds of it I would be wise not to go this tight - maybe 11, 19 and 23?

I'll add the speedo drive rubber to my list.

[Barry]

Well 23 was me being chicken but definitely don't go above 25.  No one uses 29 ftlbs. The first 2 stage figures aren't critical so whatever is in proportion to the final figure will be fine.

As general comment, you can't always trust figures from a Haynes manual. It's not their fault as they just copied it from a BMW manual which also contains some worse errors like the smaller flywheel bolts which are pretty much guaranteed to shear if you follow the book figures. Always better to step back and consider if it sounds right for the size of the bolt and if in doubt ask.

[TomHoldom]

Just got me some new NGK BPR7ES sparkplugs, and have found out the hard way that there are different terminal types!!! Thought they could all be unscrewed - apparently not. Well thats a waste of €17!! (pack of 4)
I doubt the shop will take them back with the cut packaging.

Anyone know if there is any chance of 'forcing' the 'solid' ones off?

[jp9094]

Having just changed the plugs and done the valve clearance on the '83 LS I would like to comment.

Firstly, I never back off the head bolts and just verify the torque (I use 25 Foot-Pounds). They always seem to be properly torqued.

Secondly, I replaced the old plugs with NGK BP7ES and the top terminal unscrew no problem. I thought the "R" plugs were not to be used in the r 65 motors?

FWIW