Bushmechanic Mongrel 628 Trailbike

heres a bushmechanic tool I made years ago when I had absolutely no spare money

machined valve spring seats deeper to get 65lbs seated force from the KTM dual valve springs, and faced off the upper surface of the head parallel to the cam bearing tunnel, also faced off the rocker cover parallel to the rocker arm pivots



0.75mm thick tapered spacer shell held in with brass rivets and bog, bolted together and re bored the tunnel 0.75mm higher up



made some room for serious head studs



with the top surface of the head properly parallel to the cam and the rocker arm pivots I had to face off the lower head surface parallel to the upper surface to make the cam come out parallel to the intermediate shaft

Pmsl....
No wonder why i can't find g clamp ...
Classic valve spring compressor
I like it !!

cut valve pockets with a valve

cam nicely timed itself slightly advanced with the cam lifted

needed a bit more piston to valve clearance, could have done another job in the mill but thought id show how it works with a fly cutter made from a valve.



cutter made from welding a blob onto an old valve and grinding some edges on it



i used a few spacers at the top to limit the cut depth to 0.2mm at a time



few more pics etc of other tools

bushmechanic said:

this idea was shown to me by contiman

its no different in principle to setting the piston on an angle in a mill and using a facing cutter to deepen the pocket

I have done it with only one cutting surface like a fly cutter. the result is the same as in the mill.

this one is done with a valve as the tool and gives you the same result as doing it in the engine

[youtube:37xo1wre]http://www.youtube.com/watch?v=c4W2p_8aXxI[/youtube:37xo1wre]

this one is done with a rottler cnc machine

[youtube:37xo1wre]http://www.youtube.com/watch?v=zYQ-kUhinmY[/youtube:37xo1wre]

http://www.youtube.com/results?search_q ... iston&sm=3

.

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bushmechanic said:

some more pics

the sandpaper glued to the valve is a nice one

commercially available for use with a drill and mounted in the valve guide

or use a lathe

Click to expand...

recut valve seat Neway cutters

one of the seats had a spot of corrosion that didn't clean up with a light lap so needed a re cut



nice metal underneath, the rust was quite deep, had to take 0.2mm off



narrowed, cleaned up with 30 and 60 deg cutters and lapped

I see u taken some meat off top piston ?! Isn't that gonna change compression ratio "less" just
Wondering how ya know not take to much off? Understand more clearance for the valves
Just wondering

yes about 0.2cc total, 0.1cc per pocket ... but i took some off the head as well so it will be about the same or higher CR.

its only a trailbike so im not too fussed about the CR, as long as its between 11.5 and 12.5 im happy

..

spanner said:

I made a tensioner full radius instead of the flattened off Husaberg design
to get the chain back to the original position so I can use a .8mm head gasket.
Still needs a little development, as the chain wears the tensioner will press the chain into the cam sprocket, but I am close

This is how I do my CAD analysis but it works

Next Is a manually adjusted chain tensioner.

Cheers spanner

Click to expand...

http://husaberg.org/marketplace/11326-billet-cylinder-head-24.html

fdracing said:

I made the groove in the head



Uploaded with ImageShack.us

on the pics you can see what's going on when a stud broke :? , it happens on 6 gear at 210 km/h

regarding the cam chain , I put two chain tensioner rail and two cam adjuster one in the stock place and the other one in the front , so I can adjust my timing easily :wink:

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Yes looked at putting a curved guide on the front side, but came to the conclusion that it was much easier just to make a full radius rear slipper.

Wondering if some noise is generated from that front guide flapping around.

Are you shimming the cam to get the chain tight Bushie?

That water transfer hole and the m6 cover mounting hole could have been better placed at allow for more chain adjustment.

The tensioner is a fair way out to start with, even with a new chain and stock deck/gasket.

Love that post valve porting

post valve porting LOL like a postnatal class

yes it is kind of a shim under the cam 0.75mm thick at the bottom, and thinner higher up. I would have welded it up and then rebored but my brother has the tig for a while, I also discoverd 0.75 was not quite enough so will re do it to 1mm another time.

yes I think your rear curved guide is a better solution than putting one on the tension side of the chain, yes could be noisy .... must be a pretty wild dance going on with the chain would be great to do a slo mo vid through a plastic cover

sealed the cases together this afternoon, jeebus that took me a while, 50 different mongrel parts so nothing fitted straight up

Would be interesting to see fdracing`s cam chain set up

3015 cam to rocker interference before raising cam



also hit the head



tapered shells





ground out rocker arms to clear the cam

You have some proper bushie ideas!

its good to see them work too. awsome read! keep up the good work

Gav

drive pinion lockwasher

Ive never had a drive pinion come loose with proper use of loctite but this gear has a history of coming loose and is very loose on the crank, I can push it on by hand.

so JBS idea, lock washer



ground a flat section on the gear and machined 1mm off the nut. the nut has a huge lead in champher where there is no thread so this does not affect the strength of the nut.

I ended up lockwiring mine, I'd have liked to have used your tab washer idea but when we cut a new thread on the crank we couldn't get as many threads as we would of liked. We thought a 1mm tab washer would have used up a little of our thread area. Thoroughly cleaned, Loctite 2701 and with the help of my engineer mate we clicked it up to 105nm, 5nm at a time!

Sorry to hijack your thread! Great work by the way!!!:spin::spin::spin:

awesome canolman!

good to see you got some holes through that gear

found if i put grooves in the clutch plates they last much longer



they are about 0.2mm deep and staggered from one side to the other so they don't align and create a weakpoint.

oil pickup slots in the clutch pressure plate



pic of the LHS before the cover goes on. to make the gasket reusable i put loctite 518 on the case then the gasket on top of that, then put anti seize compound on the cover. cover bolts tourqued to 8Nm, have only ever bought 2 clutch cover gaskets.



the groove for the o ring on the water passage measured 1.6mm deep on this engine, my other 2 engines it measures 0.8mm deep so i put a shim in the groove.

shimmed the kickstart shaft to 0.2mm axial play, needed a 0.6mm shim to get there.

also had to take 0.8mm off the silver spring collar on the gearshift shaft to get the 06 cover to fit on the 02 cases.

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



LHS is bolted up, ignition cover needs some wizard hat tricks, engine nearly done.

All that great work and you've got the engine upside down!

Good idea on the gasket. I got tired of ruining paper gaskets and use silicone to seal the sides together. Such a pain in the a$$.

plumbbob said:

All that great work and you've got the engine upside down!

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I might get it right one day carl