Bushmechanic Mongrel 628 Trailbike

kenny87 · Aug 8, 2015

bushmechanic said:
Spanner sent me some internal engine bling, oem water pump shaft oil seal and bearing left, same size bearing machined thinner on right

for use with a std shaft seal

Is there any benefit using standard kind of seal? I have an oil leak from the little hole next to the waterpump (weep hole?) and we have tried to replace the special bearing with the integrated seal but it is still pushing out oil through that hole. Of course we replaced the oring to but no luck and now I saw your solution and was thinking about to try that instead.

bushmechanic · Aug 8, 2015

the seal on shaft idea is better than the OEM contraption which is a special seal on the inner race of the bearing itself plus an oring between the shaft and the bearing inner.

if you want a drop in setup with seal on shaft contact orangeberg who makes a kit (see my signature for details) or make your own like spanners one shown

Goose916 · Aug 8, 2015

I got the orangeberg kit and will be installing it next saturday along with remainder of engine build. I'll let you know how it goes. Kit is well sorted, sadly, i am not!

kenny87 · Aug 9, 2015

bushmechanic said:
the seal on shaft idea is better than the OEM contraption which is a special seal on the inner race of the bearing itself plus an oring between the shaft and the bearing inner.

if you want a drop in setup with seal on shaft contact orangeberg who makes a kit (see my signature for details) or make your own like spanners one shown

Ok! Do you know how thick the machined bearing was? Something like 5-5,5 mm maybe?

bushmechanic · Aug 9, 2015

yes something like that i recall spanner said he could have made it thicker and used a thinner seal.

i have it apart the next few days and will update here with the dimensions its just the standard size bearing that has been machined thinner

kenny87 · Aug 9, 2015

Great, thanks!

WArdogG · Aug 12, 2015

Those darn seals on the OEM contraption really are *****.
Thanks guys for taking the time and posting all these cool mods to make an awesome bike even better.

bushmechanic · Aug 14, 2015

oem bearing and integrated seal measures 12.5mm deep bearing is 6201 12x32x10mm

there is a seal available via the internetzz that is 4mm deep leaving 8mm for the bearing

https://www.google.com.au/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=12x32x4+seal

and there is an 8mm deep bearing 620108 12x32x8mm

the one im using is a 6201 machined down to 6.6mm deep and the seal is a 12x32x7 but i sanded it down to 6mm wide.

in my 700 i use a slightly smaller bearing than the oem one inside a sleeve with a 5mm wide seal

or as mentioned already ORANGEBERG has a ready made kit for the job.

bushmechanic · Aug 15, 2015

useless aluminium self removed

, happened because excess loctite pushed too hard on the case , ive set the crank axial play at 0.15mm

if you need a seal make the bearing sleeve longer/thicker and put a seal in the sleeve

bushmechanic · Aug 15, 2015

titanium wrist pin has c30 hardened endcaps this one has cracked

also the wossner piston uses a longer wrist pin so im using the std wossner pin it weighed 64gm, OEM pin 72gm, ti pin 40gm, cp pin 80gm

bushmechanic · Aug 15, 2015

wossner 570 piston 8737D A

had to cut valve pockets deeper for the 3015 cam and big valves.

if using in a oem 628 you should be fine for the intakes to piston clear, the exhausts will need to be checked .. prolly just ok at a guess.

interesting piston, squishband is smaller area (same height) but the volume is made back up with a lump in the middle, my thoughts are this is good for my application since its less likely to crack in the middle.

camera went flat, need to make a pic of the cracked prox

in the meantime it looks like this one

bushmechanic · Aug 15, 2015

underside of the wossner

and newer kickstart shaft used in old cases showing where the shim needs to go

WArdogG · Aug 19, 2015

Bushmecanic, since you are running no main seal on the rhs, I assume you have had no issues with that setup? So I'm thinking of just sealing the ignition cover and leaving the seal out. Do you have some sort of lip, other than what broke off there, to keep the rhs main bearing from pushing out, or is it held firmly enough by the interference fit?

I have a casing which has cracked through the ign side main bearing, and I want to attempt to fix it as an experiment, using the steel sleeve and a spherical roller(both sides) since I can't guarantee the engineer will be able to get the alignment for the main bearing pockets 100%.

Do you have a draining hole for the oil that gets pushed into the ign cover, or do you just leave it as is? Maybe a little extra oil then?

bushmechanic · Aug 19, 2015

gday wargod yes no issues with wet ign

I drilled a 6mm hole back into the crank cavity at the bottom of the ignition cavity to let oil drain through

the sleeves I made are working well although I feel that they should be thicker, there are some drawings somewhere .. i will put them up later

there are 2 thick lips to retain the bearing one presses on the inside of the case and the other stops the bearing coming out.

the axial play of the crank is 0.15mm and the ign side bearing is honed out to a 0.5thou slip fit (not interference) the drive side is honed out to be equal in diameter to the crank.

spherical rollers both sides will stop crank spread completely but there are more flexing loads on the big end pin when the piston is 1/2 way down the stroke, very generous pin welding is not a bad idea.

WArdogG · Oct 22, 2015

Regarding the cam, would you recommend the 3015HC or would it be possible to regrind an oem cam to have less vicious lift ramp, or would you do a complete regrind to custom spec?
I would like to try a regrind on one of my cams as its much cheaper than to import something all the way out here to the southern tip of africa.

I have the cam from my 2003 FE501 with exhaust lobe worn off by collapsed cfb. I was thinking of having that welded and reground to a newer cam spec, but as mentioned in owners doc, even the newer cam profiles are still very hard on the valve train. I would rather then regrind to a better profile. Only, I dont know what this new profile spec should ideally be. I would like to eventually have all my cams ground if the first one proves to be reliable, as I'm not sure yet of the quality of the workshops grinds.

I'm not specifically looking for more performance, but i wont mind gaining some, mostly looking to have less stain on the valve gear. I will be coupling the reground cam with kibblewhite valves and dvs.

bushmechanic · Oct 22, 2015

gday wardog

the 3015 cam is a top end cam you need to go to about 13:1 to make it a nice all rounder

it gives you a smoother delivery than the stock "08" profile but unless you up the cr the bottom to mid is a bit soft. i prefer the "08" profile because it has the best balance of low end and peak torque vs top end. in my experience it is as good (nice) on the cam follower bearings as the 3015 cam.

a better alternative cam source than the 3015 is the thumper racing or webcam ktm RFS cams just need to cut the water pump shaft off .. same as for the 3015 cam. TR stage 4 and stage 5 cams or the webcams "062" profile are the ones i would use.

WArdogG · Oct 22, 2015

So you reckon I shouldn't be too concerned, the stock 08 cam is adequately lighter on the valve gear, if coupled with the dvs?
Would it be a good idea to have the trashed cam welded and reground to the 08 profile?
I would have loved to get one of those cams you mentioned, but the exchange rate is making it impossible to import anything!!! And that's why I'm thinking of trying regrinds.

I can also have valves made locally, costs about the same as a kibblewhite valve, but I can have it made to any specification and I am not limited to what they supply.
The valves are solid stainless steel, and I don't know if that is OK? Weight may be an issue, but I think the kibblewhite is also stainless but with the DLC coating. Do the kibblewhites have stelite tips, I don't know...

WArdogG · Oct 22, 2015

Also, how much weight would you say you took off in total when you reballanced that 628 crank?

WArdogG · Oct 22, 2015

Apologies Bushie for the many questions.
What sprocket ratio you running on the mongrel 628?

bushmechanic · Oct 23, 2015

yes just run the 08 its a very good cam, i wouldn't bother with any regrinds, lots of them fail. kibblewhite 96-96000 dual springs or the KTM atv set and bigger valves are worth doing.

kibblewhite valves for the rfs are stellite tipped and DLC, spanner found subaru WRX ferrea stainless valves work well , just need to be slightly shortened, ive started running a set will let you know in a year how they go.

i think i took off just over a kilo off the crank .. gearing at 16/45 or 16/47 depending on how dry the sand is.

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