Topic: piston to cylinder clearance with wiseco 836

[fire113]

hi guy's

...i am wondering what will be the best piston to cylinder clearance for an 836 wiseco kit on my 750 K1.

Found in the www that the clearance should be 0.0020" but on the wiseco-box was something like 0.001x" may be it was 0.0015" but I am not sure, have it not here right now so I can't check it.
That should be 0,0381mm - 0,0508mm

Next question what should I do with the "bigger" pistons of the set? I thought it will be better when I put them on cylinder 1 and 4 and the "smaller" pistons on cylinder 2 & 3.
I measured up to 0,01 mm, in inch it should be ~0.0003937" difference from one piston to the next piston. Is it ok or is it too much ?

...fire113

[Jim F]

you shouldn't have to worry about .0003.
I bored for my 836 kit with about .001 total clearance (.0005 per side)

good luck

Jim

[fire113]

Thanks Jim, sounds great  

I was a little bit worried about the clearance.

Now a quick breakfast and the I have to finish the engine.

...fire113

EDIT--> do I have to change the jets or will it be ok with the stock carb jets?

[scondon]

As long as you're just changing piston size the stock jets should be good to start. If you've added an open exhaust, pod filters, or performance cam, some carb tweaking might be in order.

[754]

 Fire, you may want to post this in Hi Performance section.

 Clearance depends a little on how you want to use it, and if you want to break in slowly.

 I would not run .001 clearance,  without a very long break-in, I would go a bit more as I would want to start running it hard after about 10 hours..

[fire113]

...bore and hone was already done but I was not sure about the clearance.
And now I know why I was confused about it, @ the piston-box I read 2 measurements in inch AND in mm 

This engine will only run with 836 wiseco kit, no hot cam, no rc carbs or what ever.
But the second engine  will run like hell...hope so.

I disassembled the hole engine and renewed ALL bearings and seals and chains and and and--> 12 hours later the engine wasn't finished, man thats a lot of work  I thought that I can run the bike this evening but I couldn't

[shino]

I probably sound stupid with this question but I just bought an 836 kit and had my cylinder bored at a reputable shop here. After they are through what was left of the cylinder sleeves was just like paper thick. Unfortunately I didn't measure how thick it was but is does the sleeves really only have that much thickness left in them and yet still be reliable for use? No hot cams or whatnot only the 836. How about overheating issues? Any advise on how to break it in? Help.

Any advise would be greatly appreciated.   

[fire113]

Hi shino,

...no problems with my wiseco kit  
As I drove the engine in I stayed under 6500RPM in the lower gears in the 4 & 5 the gear I don't cracked the 6000 for the first ~500-700 Km. To low RPM's are no good because the piston rings have to set.
After 800 Km I gave her a little bit more RPM's up to 7000 in the lower gears but sill stayed unter 6500 in the last gear.
As I reached 1500 Km I opened the throttle full in the 5th gear and the engine is running very good have to take gas away at 8500RPM it would like to rev higher but with the standard rods I won't find out what the max rpm is  

What do You mean with "paper thick" ? here YOu have a picture from my cylinder @ 836 bore.

Have a good one...Georg

[754]

 The sleeves shoud be thin, you bored a few millimeters out of them...

..it has worked well for thousands of people before you tried it..

[HondaMan]

Typically, the Wiseco pistons with the micro-grooved skirts require 0.0020" clearance. I run them at 0.0018" 'cuz I'm a tightwad, which calls for a little longer break-in and full cooldowns between hard runs. The standard pistons, like those found in the cheaper 836 kits, can make good use of 0.0010" clearance instead, as they are of metals more like the fins. The Wiseco pistons are a different compound, grow later when heating and shrink later when cooling than do the cylinders.

Stock cylinder liners can be bored to as much as 900cc, but have shorter life beyond the 66mm size. The 836 engines with typical 1970s/80s oils went about 40k-50k miles, so the newer synthetics should help extend that after break-in is complete.

[shino]

You guys are a Godsend! Specially to you fire113. Thanks for the pics and for the break in guidelines. Will post pics and videos as soon as the bikes up and running. Thanks again guys.