Bushmechanic Mongrel 628 Trailbike
- Thread starter bushmechanic
- Start date
-
- Tags
- 628 bushmechanic mongrel trailbike
Joined Jun 2007
4K Posts | 1K+
south east WA Australia
check squish and piston to valve clearence
Gday Mat
big end is standard, I have a PEEK coated cage but ive already welded this one so it will go in the 700, its only a lame trailbike this one. Im hoping I "never" have to change the mains.
fresh out of spam but have plenty of play dough in stock, top work by my 5yr old assistant.
0.9mm squish, HC3015 cam, intake valves to piston 1.8mm exhausts 3mm CR is about 12.5:1
Gday Mat
big end is standard, I have a PEEK coated cage but ive already welded this one so it will go in the 700, its only a lame trailbike this one. Im hoping I "never" have to change the mains.
fresh out of spam but have plenty of play dough in stock, top work by my 5yr old assistant.
0.9mm squish, HC3015 cam, intake valves to piston 1.8mm exhausts 3mm CR is about 12.5:1
Last edited:
Joined Jun 2007
4K Posts | 1K+
south east WA Australia
cam chain lengths
houston we have a problem
brand new DID chain is too long, 1 click left to start with
Brand new IWIS less of a problem 5 clicks left to start with.
I poked a feeler guage under the cam bearings, with the IWIS chain the cam can go up 0.5mm, and with the DID 1mm up.
I could hassle spanner for a custom chain guide but raising the cam will help put the rockers down closer to the valve stems.
houston we have a problem
brand new DID chain is too long, 1 click left to start with
Brand new IWIS less of a problem 5 clicks left to start with.
I poked a feeler guage under the cam bearings, with the IWIS chain the cam can go up 0.5mm, and with the DID 1mm up.
I could hassle spanner for a custom chain guide but raising the cam will help put the rockers down closer to the valve stems.
Joined Jun 2007
4K Posts | 1K+
south east WA Australia
Interesting looking piston Bushie.
I now well understand that using big bore pistons is not worth the hassle let alone the expense and far as the part availability.
A big bore and a shorter stroke would be my ideal.
nah we just need collaborate a bit and organize things ourselves, my 105mm iron liner probably should have been plated and it was a bit rough but it is still working very well.
108 x 60 with a plain big end would be interesting .. big bore Ducati
Joined Sep 2007
782 Posts | 291+
???
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
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
Joined Jun 2007
4K Posts | 1K+
south east WA Australia
looks fantastic Spanner
i will try your cad modelling program tomorrow after work and see what I come up with
the stock chain tensioner foot doesn't line up to the guide properly not sure if it is possible to correct that with your manual unit.
i will try your cad modelling program tomorrow after work and see what I come up with
the stock chain tensioner foot doesn't line up to the guide properly not sure if it is possible to correct that with your manual unit.
Last edited:
Joined Jun 2007
4K Posts | 1K+
south east WA Australia
yes looks to me like the head and the cases have been shaved down
head volume only 34cc (my other bike is 38cc) and the piston is above the top of the cases
I think I have a mitseiki pentasaurus
head volume only 34cc (my other bike is 38cc) and the piston is above the top of the cases
I think I have a mitseiki pentasaurus
Joined Aug 2009
1K Posts | 346+
Charters Towers, Australia
Gday Mat
big end is standard, I have a PEEK coated cage but ive already welded this one so it will go in the 700, its only a lame trailbike this one. Im hoping I "never" have to change the mains.
fresh out of spam but have plenty of play dough in stock, top work by my 5yr old assistant.
0.9mm squish, HC3015 cam, intake valves to piston 1.8mm exhausts 3mm CR is about 12.5:1
Great to see you have moved on from crayons to play dough !
Deep breathung Hc 3015 and 12,5:1, the sucker should fairly wail then.
.9 squish is keen with the flexing Ti pin and associated small end clearance, tight mains and big end would mediate that I spose.
Mitseki pentasaurus ? I don't speak engineer but is it a relic 5 axis cnc mill made from fossilised T-Rex stool ?
Now we've seen your bottom end, how bout you give us some head.
Joined Jun 2007
4K Posts | 1K+
south east WA Australia
it is said that the Greeks were the ones who invented sex
however it was some time later that Italians had an epiphany and introduced women to it.
the story of the mitseki pentasaur is easily googled
https://www.google.com.au/search?q=...annel=rcs&gfe_rd=cr&ei=3lfUU7ejA-nC8gfUiYHICw
according to the internet it comes from a pickled velociraptor chair with 5 legs
Joined Jun 2007
4K Posts | 1K+
south east WA Australia
im hoping my teflon crayons will help ease the pain
apparently 0.5mm squish works ok with the 82mm crank
I inadvertantly ran 0.8mm squish with a 105mm JBS headgasket on a 100mm bore that worked ok too.
Last edited:
Joined Jun 2007
4K Posts | 1K+
south east WA Australia
lovely pantograph, it blows me away reading grandads old machinery books how long ago they were making hydraulic servo operated copying machines
yes the HC has different lobe timing and lifts, I had to advance it a few degrees to get their specs last time i used it.
its not my favorite cam but it will do for this bike.
raising the cam first then will degree the cam again and recheck PTV clearance, cam gear is already slotted
the bottom surface of the head was not parallel to the cam bearing tunnel ... it keeps getting shinier and smaller all the time LOL
cut the valve spring pockets 0.5mm deeper today to get the seated force back down to 65lbs
yes the HC has different lobe timing and lifts, I had to advance it a few degrees to get their specs last time i used it.
its not my favorite cam but it will do for this bike.
raising the cam first then will degree the cam again and recheck PTV clearance, cam gear is already slotted
the bottom surface of the head was not parallel to the cam bearing tunnel ... it keeps getting shinier and smaller all the time LOL
cut the valve spring pockets 0.5mm deeper today to get the seated force back down to 65lbs
Joined May 2010
592 Posts | 247+
San Francisco, California
ok, so . . . . for those of us that can change our oil and, on occasion adjust our valves, can you explain the use of the silly putty? I understand the concept of squish piston/cylinder/head clearance, but i'm curious as to how the putty helps you determine. Or, is is just where your kid decided to smear putty and you took a pic cuz it was funny and you knew it would confuse idiots like me ;-)
Joined Jun 2007
4K Posts | 1K+
south east WA Australia
Gday Goose
if you watch DR_Cs youtube videos there is a section where he does this but with far more professional expressions and yellow clay .
https://www.youtube.com/watch?v=jaxucrs2ZrU
you just measure how thick the clay is after the engine has rotated 2 turns
if you watch DR_Cs youtube videos there is a section where he does this but with far more professional expressions and yellow clay .
https://www.youtube.com/watch?v=jaxucrs2ZrU
you just measure how thick the clay is after the engine has rotated 2 turns
Similar threads
Register CTA
Register on Husaberg Forum! This sidebar will go away, and you will see fewer ads.
Sign Up
