Topic: 836 big bore and oil leaks.

[kghost]

Ok I have been doing my homework.

Seems like a lot of us running the 836 weisco kits are experiencing some oil leak issues.

Mine seems to be caused by more pressure than stock in the crankcase. There seems to be alot of variation as well in how the breather hoses are being run.

I ran mine per Honda on my K2. That is to say the breather vent on the valve cover to the back top of the oil tank. The Line from the rear of case went to the rear of the oil tank ( the fitting about midway down which is connected internally to the upper one via the tube inside the oil tank).

Now with a good gasket on my dipstick the oil tank and motor are pressurizing. This is causing leaks at the valve cover.

I would be interested to here from others. I would like to know what their breather arrangement is and how much venting they are experiencing with the 836 Hi comp pistons.

I talked to my local dealer. The manager there is an old 750 drag racer. He recalls that all the big bore motors in the day had a lot of crankcase pressure. He recalls that they used to mod them. They would drill and tap the Tappet hole covers on the 2+3 intake valves. Then thread in a nipple and run a line to a catch tank. This stopped thier vent/pressure problems. Also the location of the nipples would let very little oil escape just pressure.

That being said, I am considering tapping my 2+3 covers and routing the lines into the stock airbox at the top. Thus I would continue to have normal venting to the oil tank but excessive pressure would be relieved. It would also keep me from having to route a line down between the swing arm where oil could leak on the ground/Tire.

Your thoughts and comments?

[Spear]

Hey K (or is it KG?) Either a K series ghost or a kg (heavyweight) host! Pardon my attempt at wit. That's a real mind numbing question that is. I run an 812 kit but the only oil problem I have is slight seepage from around the neutral switch under the belly. I gather from looking at your avatar photo that you have an oil pressure gauge tapped into the oil journal? What sort of readings are you getting at what sort of revs? Not that I can help you at all, I'm just curious about the gauge. I've seen a few machines with them fitted and was wondering if they work. I'm old school when it comes to mechanics. The older machines (bikes and cars) were very uncomplicated and had far fewer bells and whistles than the modern ones. I reckon if you can see all those readouts, then you have too much to worry about in the event something could go wrong. If you can't see it, then it ain't worth grieving over! I can imagine how a space shuttle pilot feels. Spends all his time looking at instruments, dials and gauges wondering what is gonna give first. Then bugger me, a bit of crap falls off some external component and damages a wing. Makes for a spectacular re-entry, unfortunately. Mate, you wouldn't get me up in one of those things for love or money. I'd be spending too much time watching all the dials instead of enjoying myself. I just love my speedo, tacho, and panel of idiot lights - especially the oil pressure light that loves to stay on up to about 2,000rpm when she's real hot! Still goes like the clappers, though. Spear

[kghost]

Spear, I drive big iron around the sky for a living. Totally at home looking at the gauges.

But as to the oil gauge: The reading on startup with cold oil is about 50 psi. when warmed up its about 20 psi. Both at idle.

Under riding conditions its at about 56 psi at 4200 rpm. From my research the bypass on the oil pump housing kicks in about there. (figure I saw said 57 psi high and 7.8 psi low). The idiot light should come on at about 8 psi (7..

I live in deep south Texas where it gets Africa hot. If I really flog it (on a 100 F/38 C day) I can get the light to flicker on and off at about 750-800 rpm. Doesn't do it often. The oil cooler on the front really helps.

The old rule of thumb with plain bearing engines was about 10 psi per 1000 rpm. Although much past 60 psi doesn't help.

Sigh, but theres the oil leaks. Anyone?

[cben750f0]

i have a wiseco kit and have a weep at the head gasket, and it dont matter hard many times i retorwue the head(which required engine removal).. i still have it, have been told that if you clean up the area, and spyay heat proof paint over the area between the head and cylinders, sometimes this is enough to stop a seep, havent tried it yet... anyone esle?..peace

[kghost]

Cben750f1,
 Whats your breather hose configuration and how much pressure are you getting out of it?

[cben750f0]

breather from the head,to little canister under the battery, then to the airbox.... soon to be, from the head to a little breather filter...peace...

[carsholduptraffic]

i had the same problem kghost........
when i ran the breather hoses as per honda on my 836 it would weep like crazy, and didint when i took the big hose off the oil tank. so i plugged the tank pipe, left the little hose from the tranny in place, and used a catch bottle. i run a smaller baterry, so it fitted in beside the battery. went well till i moved to canberra and it's frosty winters. i had emulsified oil in winter, due to being only 15min ride to work. i then put a tee fitting in the breater hose, put it back to honda way, and put a small filter on the tee. less weeping, and no oil emulsifying. and cheap.
i run an oil gauge as well and picked up from custom chopper imports in oz.

[cben750f0]

thanks carsy, will try that, BTW need a bigger pic of the burnout... havea set of old school pos i am gonna run, so wont be able to put the line to the air box... so am just gona run a small filter... ..peace

[carsholduptraffic]

kghost, just use a tiny filter (k&n makes nice small breather filters) and put it under the seat over the oil tank.

[cben750f0]

WAY TO GO MATIE!!!... cool will try and find one... here is a pic of my pods...way cool ..peace

[MotoDave]

I've always had both the valve cover hose and top oil tank hose routed to a catch bottle.  Putting a small air filter on it is probably a good/better idea.  My motor used to smoke when hot and would puff a lot from the breathers.  I'm almost finished reassembling my motor will all new valves/valve guides and yes, the Wiseco 836 kit   I'll be running it for the first time this weekend.  I'm hoping not to see smoke again...

[cben750f0]

as my mechanic said, they all smoke from the breather when they are hot....have never had smoke out the exhaust though... so if thats the only place its happening then i am happy.. BTW let us know how the motor goes... was a huge jump in power for me...peace

[MRieck]

I've always had both the valve cover hose and top oil tank hose routed to a catch bottle.  Putting a small air filter on it is probably a good/better idea.  My motor used to smoke when hot and would puff a lot from the breathers.  I'm almost finished reassembling my motor will all new valves/valve guides and yes, the Wiseco 836 kit   I'll be running it for the first time this weekend.  I'm hoping not to see smoke again...

It shouldn't with the new rings.

[kghost]

Yeah MReik, I know that.
 The kicker is mine doen't smoke, burn oil, and has great compression. The carbs are set up and spot on.
 Just seems like alot of crankcase pressure. But it seems like everyone has more than stock.
What gives?

[carsholduptraffic]

more ring leakage than a stocker due to bigger ring circumference maybe??
 mine used to blow the hose off the oil tank when revved before i ditched the stock setup. motor still went fine, didn't use oil- just leaked it. so i never solved the story, just the symptoms.
i never got around to a proper leakdown test, but compression was good, so i rode and was happy!

[Sam Green Racing]

Hi all you big borers,

Am I pleased I found you, as I am just starting to build an 836 Wiseco/Megacycle motor.
The problems you have encountered have all been noted and will hopefully save me any frustration when it runs next year.
We have just started our 3rd season in classic sprinting (drag racing) still useing a stock motor in a 1970 spec Daytona chassis.
Can't wait for next year and the big motor.

Sam Green. England.

[cben750f0]

no, i got it dyno'd...66hp at the wheel.. which i thought was ok... other than a weep. at the head gasket, the ol girl fly's, had a bloke on a 04 sv 650 try to catch me up falls creek..(ppl in oz will know where i am talking about) couldnt, then when he went dont the twisties in front couldnt get away, granted its alot harder to get the bike to change direction and such, but i an more than pleased with the out put, and the acceleration... you will be too..peace

[Sam Green Racing]

Cben,

What did you have at the rear before the 836.

[kghost]

Cben, I'm Kinda curious about your set up.

I'm still running the stock airbox and exhaust. For originality sake.

On the Cafe I'm Building now I'm gonna run velocity stacks and maybe some 31 mm CR's if I can find some without a morgage on the house. Also gonna port the heads and run a free flowing 4-1. hoping for a bit more than 66hp.

P.S. the 836 with the Web 41a cam does a great job of increasing torque. Especially down low over stock

[cben750f0]

i think from factory they made 65hp at the crank... so its a pretty good upgrade.. runnning tranzac exhaust,dyna's',vf1000 coils,UNI filter,standard cam, and no head work... thats why i was so happy with the numbers..peace

[Sam Green Racing]

Hi Kg,

Have you heard of any other BHP readings on K models with just the 836 piston kit.

[kghost]

No, thats why I was curious what he was running.

I have two K2's one with and one without the 836. The one with the kit and cam is allot better than stock.

I would like to dyno mine. Just haven't got the chance. Next ones gonna be all out though.

My local Honda dealer is an ex-drag racer. His bike was like 1080 cc with fuel injection on alcohol. I would run 9's in the 1/4 back in the day.

[Sam Green Racing]

Kg,

Hurry up and get it dynoed and give us a clue.

The motor we are running now is a stock K7 with 31CRs and 4 into 4 open as on the factory bikes of the seventys.

It puts out 61 at the back end and weighs in at 396 pounds.

Chris the rider adds another 266 pounds.  His best time is 13.3 wind assisted at 101mph, and a top speed of 127mph at 9000rpm.

The new motor is a K2 with the same carbs and exhaust.  It's having the head reworked the 836 and a Megacycle cam that was made to work well with the 836 Wiseco's.

Looking forward to a few years fun.

[cben750f0]

this is the chart

[Sam Green Racing]

Cben, Did you not get it dynoed before you did the conversion.