'84 1200 engine for a '82 GW

[canuckxxxx]

joedrum » Fri Jul 03, 2015 10:32 am[/url]":130v3weo]
hmmm to me ...the numbers are not that bad ....oil is going to raise compression in old motor thats been sitting ...

That is what I'm thinking Joe. I can freshen those 1100 heads by a light lapping too, before putting on the 1200.

 

[slabghost]

Don't forget to enlarge the valve reliefs on the pistons.

 

[canuckxxxx]

slabghost » Fri Jul 03, 2015 10:58 am[/url]":y5ck9gdm]
Don't forget to enlarge the valve reliefs on the pistons.

Good point. I will have to see how Joe and Eric did it.

 

[slabghost]

Joe used an angle grinder. I think a 2" disk sander on a drill will suffice and be a little less aggressive.

 

[ekvh]

I used double faced tape and sandpaper on the intake valve. Worked fairly well. Wrap the paper a little larger than the valve. Mark the valve stem when you start and take enough to give 70-100 thousandths clearance. I used a drill on the stem. Now that I have done it once, the next time I would put the paper on all eight valves and do them all at once. The exhaust valves clear, but I would feel better with a little insurance. I have another one waiting. My hip just keeps arguing with me. There's a good write up and how-to at Saunders on the bgirl, one of the stickies.

 

[joedrum]

it was over in short order lol....it was angle grinder with 4" hard disc ....it actually enhances flow in my opinion

now if your going to use 1100 cams ...theres a good chance you might not have to grind pistons ....this is very easy to check ... i figured out a way with one old gasket and one head ...i could see exactlly where everything was like where piston was at ....and with valve adjusters you can figure what kind of clearence you have ... by adjusting down till something hits ....1100 cams are quite aggressive too though theres probably piston work to do...what cams you use here means alot in my opinion ...ive used all the cams in one bike ..theres no doutb in my mind the the 1100 motor for sure like the 1000 early cams the best ...like it was a perfect match ... :BigGrin:

 

[ekvh]

I'm pretty sure the 1100 cutouts match up with the 1000 cutouts, but the 1200 were set in towards the center a little more. Because of this, I think the 1100's will hit. The 1200's also came in at a shallower angle, closer to parallel with the piston top and combined with smaller diameters needed less cut out. The 1100's don't have as much lift as the 1000, but it's very close to the same.

I'd like to try a set of 1100 cams on mine, but I wouldn't have ignition unless I drilled and tapped a C5 to it. Great idea!!! Someone give me $500, quick.

 

[canuckxxxx]

Even though I will be using the 1100 cams, I think I Should make deep enough cutout so I could put 1000 cams later without taking heads off.

Btw, I have one good used head gasket from taking off the 1200 heads so can use that for mocking up.

 

[joedrum]

well there goods pics in either the hooch or jyd threads ....rather barbaric but good pics :BigGrin:

 

[canuckxxxx]

Sounds like "cave tech"

 

[ekvh]

It works.

 

[sgq700]

if you want to be sure, go get some silly putty(like the kids play with) and roll it out to about .050" thick, cut it round to fit the top of your piston, then put the head back on(with old gasket) set the timing belt and adj the valves, rotate the engine by hand for 2 rev's(unless you feel like it is binding.. then Stop and remove head) as that will give 1 complete turn of the camshaft then remove and measure the areas of contact and you will see exactly where and how much you need to grind el pistone for valve clearance! that is how we did it on the old race motors

 

[canuckxxxx]

I've got grandkids so we have lots of Play Dough. :smilie_happy:

 

[canuckxxxx]

I've been reading "the story of Hooch". :read: Very interesting, Joe...lots of good info as to what parts fit and what don't. Also, very inspiring with the performance you got.

Eric, I've been looking through "1200 into 1000 chopped" to see how you cut the valve reliefs but am not having luck. The first post of that thread shows the piston top with the reliefs already there so maybe there is another thread...Can you direct me to right spot? :help:

Thanks :thanks:
Brian

 

[canuckxxxx]

Started taking the old '82 apart today. Here is a shot of the 1200 head (bottom) compared to the 1100 head (top) that is still on bike. You can see how much bigger the ports are on the 1100.

image

• canuckxxxx
• Jul 4, 2015

 

[canuckxxxx]

About 1 3/8" vs 1 1/4"

 

[joedrum]

hmmmm so you have decided to go 1100 heads ....i think that is good move ....the oil orfice of the 1200 motor needs to go in 1100 head...its bigger and handles the extra oil flow of 1200 motor .....at least thats what i did ...there are some back timing cover issues to deal with ...but to me they were small ...

ive got a 1200 in a 1100 right now that needs finishing ...it is a 84 yr motor ...cant wait to get it up and going also .....

 

[canuckxxxx]

After I did that compression test, where the compression went up after squirting oil in cylinders, I got thinking: :headscratch: The oil probably only affected the bottom part of the cylinder and yet there was a big change in compression.

I don't know what thread it was, but I remember it being said that there can be some glazing on the bottom of the GW cylinders that can be broken up with some sandpaper, for rings to seat properly. Does anyone remember that? :fishin:

Just wondering if I should do that on this 1200.

Thanks
Brian

 

[joedrum]

that me that said and did that to the motors i work with ...im rather a heads off guy when it comes to bringing these motors back without rebuilding it ...and gambling on lower end being tight ...witch is a rather dood gamble on oldwing motors ...yes glazing should be gone and it tough also ...use smart hands as no digging below cylinder walls can happen ...

 

[canuckxxxx]

Does anyone know the cam specs for a '84 1200?