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Advice on skimming head please!
Posted: Sat Jan 30, 2010 6:14 pm
by blueflag
Hi all,
I'm thinking of lightly skimming the head on my triarm, I've already removed the quietening gears on the cams.
I know I need to displace slightly the gear train that transmits rotation from the crankshaft to the top end to allow me to drop the head without too tight a mesh on the cam gears. I was wondering if it's possible to remove the quietening gear on the gear that meshes with the crank as well? (I think the answer is probably no BTW

)
Thanks again!
Mike
Re: Advice on skimming head please!
Posted: Sat Jan 30, 2010 8:13 pm
by racesupplies
Unless you know what you are doing,dont,its tricky.Why do you want to skim the head?
Re: Advice on skimming head please!
Posted: Sat Jan 30, 2010 8:41 pm
by blueflag
It's a race bike (my first 400 though).
I'm lucky enough to be a toolmaker, so the machining shouldn't be a problem (don't tell the boss though!). My concern is if I introduce even a small amount of backlash into the train it'll mean a valve calamity!
If it's not worth the hassle i.e. limited gains, then I'll probably leave it.
Mike
Re: Advice on skimming head please!
Posted: Sat Jan 30, 2010 9:03 pm
by racesupplies
Cor blimey,where do you start? Its beyond me to tell you what to do really,but for what its worth. You need some backlash,otherwise as it warms up the gears will bind and transfer the load into the shells or the head.Dont give up,just ask someone that has done it.Get some sort of drawings from them if youre going to do it yourself.Dont guess it.
Re: Advice on skimming head please!
Posted: Sat Jan 30, 2010 11:13 pm
by Cammo
Whatever you skim off the head you'll need to add to raise the cam carriers via a shim plate etc.
Re: Advice on skimming head please!
Posted: Sat Jan 30, 2010 11:14 pm
by racesupplies
Can you do that on ome of those?
Re: Advice on skimming head please!
Posted: Sat Jan 30, 2010 11:54 pm
by blueflag
The cam carriers are part of the head casting, otherwise it'd be easy! If it wasn't for the quietening gears (they call them scissor gears on Suzuki V twins) it would be simple if a bit time consuming to replicate the backlash. You're right though Racesupplies, unless I'm sure it's probably best not to bother....

Re: Advice on skimming head please!
Posted: Sun Jan 31, 2010 9:42 am
by racesupplies
I took a light skim off the head,and the bulk off the block.Then had undersize gears made for the cams.We were fitting one off slotted hubs at the time so the geras were going to be made anyhow.Ive got a 29 motor here with an offset idler gear,but my mate makes gears so we went down that route.
Re: Advice on skimming head please!
Posted: Sun Jan 31, 2010 4:12 pm
by blueflag
That's a nice sounding solution. I like it........

Re: Advice on skimming head please!
Posted: Mon Feb 01, 2010 4:29 am
by Cammo
DataRacer wrote:Whatever you skim off the head you'll need to add to raise the cam carriers via a shim plate etc.
racesupplies wrote:Can you do that on ome of those?
I guess not! I presumed it was the same as the vfr's.
