'84 1200 engine for a '82 GW

[dan filipi]

slabghost » Today, 6:46 am[/url]":3dh8at2v]
I wonder if there is a difference in head height from the gasket to the cam journals?

I just measured, they are the same as measured from deck to cam shaft.

 

[ekvh]

I had them facing the same way. I had a new belt and I wrapped it so that half of it was on each pulley and held it as tight as I could. The keyways looked perfectly lined up and the timing marks were lined up as well.

 

[slabghost]

Well that settles the possibility of head differences affecting cam timing.

 

[dan filipi]

And pullies.

 

[joedrum]

if crank is at tdc ....i cant see how moving cam one tooth doubles it ... when you advance the other side at cam pully your not doubling anything ..your just matching the other side ...seems if it doubles it cause you went both ways in moving cam one tooth ....i cant see getting more degrees than the nine ?

 

[canuckxxxx]

All the cam specs that are shown in the manuals are in degrees of crank rotation relative to TDC and BTDC. All my reading are from the degree wheel that is on the crank. The crank makes 2 rotation for 1 rotation of the cams. So for the crank to drive the cam 9 degrees it has to turn 18 degrees. So that is the doubling that I was talking about. I'm making changes at the cam wheels but it has double the affect at the crank.

 

[canuckxxxx]

So I now have the cams advances (using offset keys) so that have intake opening at 5 degrees BTDC which is the factory setting for the 1100 cams. Went for a ride: not as torquey as with 15 degrees advance but better than 3 degrees ATDC.

Took new compression readings:

1. 142
2. 147
3. 145
4. 142

Kind of ho-hum. Bike is rideable as-is until compression comes up or I put new rings in this winter.

Brian

 

[joedrum]

hmmm ive thought about it all i may try one tooth advace on hooch soon .... i think ive got all things figured now ...im glad this thread and topic came along seems it took this and everyone thoughts for me to see things for what they are great discussion

 

[dan filipi]

Looks like it adds up to nearly a tooth if I'm following?

 

[joedrum]

seems setting right or one tooth off is not right so ... best of the two seems best and it seems right didnt really make brians any better .... opcorn:

 

[slabghost]

canuckxxxx » Thu Jul 23, 2015 1:14 pm[/url]":1ioxx7e6]
So I now have the cams advances (using offset keys) so that have intake opening at 5 degrees BTDC which is the factory setting for the 1100 cams. Went for a ride: not as torquey as with 15 degrees advance but better than 3 degrees ATDC.

Took new compression readings:

1. 142
2. 147
3. 145
4. 142

Kind of ho-hum. Bike is rideable as-is until compression comes up or I put new rings in this winter.

Brian

You may find better performance advancing the cams another 5 or 7 degrees. Ignition is timed for cams opening at 10btdc.

 

[canuckxxxx]

joedrum » Thu Jul 23, 2015 12:26 pm[/url]":2i6nzoqj]
seems setting right or one tooth off is not right so ... best of the two seems best and it seems right didnt really make brians any better .... opcorn:

Well, Joe, let's face it...this engine that I bought is a POS. Don't get me wrong, I'm not giving up on it. But I will get by the way it is, for now, and tear it down this fall and winter and rebuild the whole thing. I want to know that it is running right.

 

[canuckxxxx]

slabghost » Thu Jul 23, 2015 12:56 pm[/url]":2b0sxiv2]

canuckxxxx » Thu Jul 23, 2015 1:14 pm[/url]":2b0sxiv2]
So I now have the cams advances (using offset keys) so that have intake opening at 5 degrees BTDC which is the factory setting for the 1100 cams. Went for a ride: not as torquey as with 15 degrees advance but better than 3 degrees ATDC.

Took new compression readings:

1. 142
2. 147
3. 145
4. 142

Kind of ho-hum. Bike is rideable as-is until compression comes up or I put new rings in this winter.

Brian

You may find better performance advancing the cams another 5 or 7 degrees. Ignition is timed for cams opening at 10btdc.

I think you're right Slab. When I had it advanced 15 degrees it had awesome torque but it really went through the gas. But 10 BTDC might be the ticket.

I would also like to try the 1200 heads and cams. Do you think I could reuse the head gaskets that are on there now if I put 1200 heads on?
Brian

 

[ekvh]

My experience was that advancing the cam boosts compression.

 

[joedrum]

no brian head gaskets reuse would be big gamble to make ... run it awhile and enjoy .. try atf in fuel for awhile to help clean things ..i doutb the rings are in bad shape ..just needs working in id say

 

[slabghost]

canuckxxxx » Thu Jul 23, 2015 4:53 pm[/url]":35vnjv6t]

slabghost » Thu Jul 23, 2015 12:56 pm[/url]":35vnjv6t]

canuckxxxx » Thu Jul 23, 2015 1:14 pm[/url]":35vnjv6t]
So I now have the cams advances (using offset keys) so that have intake opening at 5 degrees BTDC which is the factory setting for the 1100 cams. Went for a ride: not as torquey as with 15 degrees advance but better than 3 degrees ATDC.

Took new compression readings:

1. 142
2. 147
3. 145
4. 142

Kind of ho-hum. Bike is rideable as-is until compression comes up or I put new rings in this winter.

Brian

You may find better performance advancing the cams another 5 or 7 degrees. Ignition is timed for cams opening at 10btdc.

I think you're right Slab. When I had it advanced 15 degrees it had awesome torque but it really went through the gas. But 10 BTDC might be the ticket.

I would also like to try the 1200 heads and cams. Do you think I could reuse the head gaskets that are on there now if I put 1200 heads on?
Brian

I've been known to reuse gaskets. But head gaskets I would not even try to reuse unless they were just unavailable. Advance it to the 10btdc and it'll better match up with the ignition. Check compression after a couple hundred miles. You may find that motor is just fine.

 

[canuckxxxx]

slabghost » Thu Jul 23, 2015 5:44 pm[/url]":yt0kvx9i]

canuckxxxx » Thu Jul 23, 2015 4:53 pm[/url]":yt0kvx9i]

slabghost » Thu Jul 23, 2015 12:56 pm[/url]":yt0kvx9i]

canuckxxxx » Thu Jul 23, 2015 1:14 pm[/url]":yt0kvx9i]
So I now have the cams advances (using offset keys) so that have intake opening at 5 degrees BTDC which is the factory setting for the 1100 cams. Went for a ride: not as torquey as with 15 degrees advance but better than 3 degrees ATDC.

Took new compression readings:

1. 142
2. 147
3. 145
4. 142

Kind of ho-hum. Bike is rideable as-is until compression comes up or I put new rings in this winter.

Brian

You may find better performance advancing the cams another 5 or 7 degrees. Ignition is timed for cams opening at 10btdc.

I think you're right Slab. When I had it advanced 15 degrees it had awesome torque but it really went through the gas. But 10 BTDC might be the ticket.

I would also like to try the 1200 heads and cams. Do you think I could reuse the head gaskets that are on there now if I put 1200 heads on?
Brian

I've been known to reuse gaskets. But head gaskets I would not even try to reuse unless they were just unavailable. Advance it to the 10btdc and it'll better match up with the ignition. Check compression after a couple hundred miles. You may find that motor is just fine.

I'm working on some new offset keys that should give 10 BTDC :builder: :music2: :beg:

 

[slabghost]

Sounds great to me. Cams designed for the motor were set at 10 btdc. So I'm thinking the 1100 cams will serve best at 10 btdc or maybe even a bit more advanced.

 

[canuckxxxx]

The trouble is that the 1100 cams are designed for 5 BTDC for intake opening, 5 ATDC for exhaust closing. When I advance the intake to 10 BTDC the exhaust will close at TDC. Should give increase in torque though but might affect gas mileage.

I filled up this AM after I got it all together with 5 BTDC so I think I will ride like this so I can get a gas mileage check. Then I can see if it gets way worse at 10 BTDC.

 

[slabghost]

canuckxxxx » Thu Jul 23, 2015 9:59 pm[/url]":b89l6pfh]
The trouble is that the 1100 cams are designed for 5 BTDC for intake opening, 5 ATDC for exhaust closing. When I advance the intake to 10 BTDC the exhaust will close at TDC. Should give increase in torque though but might affect gas mileage.

I filled up this AM after I got it all together with 5 BTDC so I think I will ride like this so I can get a gas mileage check. Then I can see if it gets way worse at 10 BTDC.

Actually if intake opens @ 5btdc Exhaust opens @ 45 bbdc . So 10 btdc on intake will have exhaust opening @ 50 bbdc and closing @tdc.
Your bike your choice.