850 Head Job

ML · Mar 27, 2011

Here's some pix of my 850Mk2 rebuild. The motor has done lots of miles and used hard over the past 7 years. About a year ago it started smoking out of the RH cylinder and generally started to get tired but ran until one day it just would not start.

The head was also a cosmetic mess - on the LH side it had 2 broken fins which really irritated me. The common idea was to replicate the shape from scrap fins and tack weld them on. However, there's this one man auto engineering shop here in Melbourne called Woodie's and does some special stuff. He builds up the broken fin with ally weld bead after bead. Then he inserts a narrow grinder and profiles the fin and dresses it down with a linisher. Then the head goes into a cleaning process call Hydroblast and the end result is stunning to say the least.

Here's why the motor's been pulled down for a total rebuild. Pistons on 0.020". Cam was good and the big ends OK on STD.

Here's the finished result

cjandme · Mar 27, 2011

looks good now!! Cj

Jeandr · Mar 27, 2011

The head looks great, is hydroblast the same as soda blasting?

Jean

ashman · Mar 27, 2011

Nice head job hehehe

Tim_S · Mar 27, 2011

Please explain the hydroblast process to us? Looks good !! 8) Now you have a bigger job ahead of you to make the rest of the motor pretty .... :lol:

Tim_S

Carbonfibre · Mar 28, 2011

Its easier and cheaper to repair broken fins by welding in shaped sections of aluminum sheet, and this also means less heat is put into the head.

tocino · Mar 28, 2011

Looks great. My engine guy called it "HydroHoning" but it's got to be the same process. I think it's blasting with dry ice (or at least a very soft material suspended in water) so that it doesn't tear up the metal or get impacted where you don't want it.

Anyways, I also just got my head back (MkIIA) and the results are as impressive. Upon first look you'd swear it's been painted with aluminum paint. Here's mine before and after :

swooshdave · Mar 28, 2011

tocino said:
Looks great. My engine guy called it "HydroHoning" but it's got to be the same process. I think it's blasting with dry ice (or at least a very soft material suspended in water) so that it doesn't tear up the metal or get impacted where you don't want it.

Anyways, I also just got my head back (MkIIA) and the results are as impressive. Upon first look you'd swear it's been painted with aluminum paint. Here's mine before and after :

Is that the same as soda blasting?

Jeandr · Mar 28, 2011

swooshdave said:
Is that the same as soda blasting?

Now pay attention Swoosh, I asked the same question earlier :roll:

Jean

cjandme · Mar 28, 2011

Yesterday i was gonna ask if the head had been painted with aluminum paint, thought the studs looked as though they had paint on them, glad i'm not the only one. they sure look good, that's also what made me think that they had been painted after they were blasted- almost looked too good. Cj

swooshdave · Mar 28, 2011

Jeandr said:
swooshdave said:

Is that the same as soda blasting?

Click to expand...

Now pay attention Swoosh, I asked the same question earlier :roll:

Jean

Yeah, but you got the same answer I did. :?

ML · Mar 29, 2011

Hydroblasting - I don't really know what it is as Woodie won't reveal whats in it. He only said a water solution.

Oh by the way Carbonfibre - tacked on fins look shite. That's why I went for the build up process. And the heat has not affected the head at all.

grandpaul · Mar 29, 2011

Soda blasting is Soda blasting.

Hydro blasting is not soda blasting.

Soda is dry, anything with "hydro" in it implies water.

pelican · Mar 29, 2011

looks amazing no matter what was used.

Carbonfibre · Mar 30, 2011

ML said:
Hydroblasting - I don't really know what it is as Woodie won't reveal whats in it. He only said a water solution.

Oh by the way Carbonfibre - tacked on fins look shite. That's why I went for the build up process. And the heat has not affected the head at all.

Properly welded on replacement fins are impossible to tell from original, but maybe not the type of thing to be attempted by less experienced welders, who need to charge about 3 times the price for building up with filler rod.

Tintin · Mar 30, 2011

grandpaul said:
Soda is dry, anything with "hydro" in it implies water.

Actually no, some soda blasting processes use a double nozzle or however they call it where an outer layer of water sort of washes away the soda dust. I wouldn't call this hydroblasting however.

Tim

dynodave · Mar 30, 2011

cjandme said:
Yesterday i was gonna ask if the head had been painted with aluminum paint, thought the studs looked as though they had paint on them, glad i'm not the only one. they sure look good, that's also what made me think that they had been painted after they were blasted- almost looked too good. Cj

Heads and crankcases (&gearboxes) were silver/aluminum color painted new from the factory. It is when the paint comes off that they start to get white and dark stained from corossion.
If you don't paint them again while clean, they will look like crap after one season if ridden all weather like a touring bike should....

Jeandr · Mar 30, 2011

Probably a good reason to paint them black, at least oil and grease won't show as much as on bare aluminium.

Jean

rvich · Mar 30, 2011

I have seen some guy on Ebay advertising "vapor blasting"

http://cgi.ebay.com/ebaymotors/ws/eBayI ... MEWAX%3AIT

http://www.vaporblast.com/

http://www.answers.com/topic/vapor-blasting

swooshdave · Apr 1, 2011

Here's more info. This on a Gold Star.

http://www.jockeyjournal.com/forum/show ... hp?t=83935

Before

After

"Vapor blasting" uses no volatile or toxic chemical vapors in cleaning your motorcycle parts. Vapor blasting uses only glass bead, clear water, and a little detergent to wash away years of dirt and oil, carbon and corrosion. The slurry mixture is pumped to the mixing gun where it is propelled by compressed air against the dirty metal surface. Unlike dry-grit blasting, the vapor-blast mixture is so soft it cannot abrade away metal from your fine machined surfaces so it is unnecessary to mask those surfaces or pipes during blasting.

http://www.vaporblasting.biz/index.html

850 Head Job

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