1170cc question

No eBay APP ID and/or Cert ID defined in Kunena configurationHere is another set. I think that $200 is very expensive.

otakar wrote:

Wrong, not all 82 cams were the same. LTD/CSR/Specter had one set of cams, J had a different set of cams and the GPz had a different set yet. And I did look it up, you do have an electronic tach so the cams will work. The 82 and on GPz cams were the same. If you want to spend $200 than just spend $300 and get a real set of cams that have at least .400 lift on them. You should be able to go as high as .410 lift with little to no head modifications.

OH, I am confused now. I had a thread a while ago that cleared it up for me, but it is clear as mud now...

kzrider.com/index.php?option=com_kunena&...ew&catid=2&id=321585

the link near the bottom of page 1 has somebody's measurements, and the 82 GPz seems the same as the "J" cams...

Either way I am not going to get those cams from the guy, I will just wait till I have more money, and till I find some for a decent price.

Now you have the idea. There in fact were three different set of cams. they varied in lift and duration. Most people do not have a method for measuring duration on a set of removed cams. The simplest way to tell is by the part #s you will notice they are not all the same. The problem in buying these "stock" cams is that people say that they are GPz cams when in fact they are only J cams or CSR cams. ALL GPZ cams from 81 on were about .360 lift and about 280 duration. your cams are 10* less duration and about .320 lift.

otakar wrote:

Now you have the idea. There in fact were three different set of cams. they varied in lift and duration. Most people do not have a method for measuring duration on a set of removed cams. The simplest way to tell is by the part #s you will notice they are not all the same.

Well, actually :blush: I am more confused now! I was going to get some 82 GPz cams and was told that they are basically "J" cams. I got a set of those for free and was told to keep my eyes open for 83-84 cams as they are higher lift.

Anyways, regarding the 1075 pistons question; what would keeping the stock head put my comp up to? would the GPz head then lower it again?

To go to GPz cams in your case would make a nice diference. that is .040 extra lift (1mm) if you go to .400 lift you would increase the lift by 2mm. I went to .420 lift that gave me an extra 2.5mm But I actually decreased my duration to 260* this still gives me very good low end and a very broad power band. To go with more duration makes the engine quite unfriendly in lower rpm ranges and makes it much more difficult to set up your carburetors. I would recommend a good .380-.390 lift cam with 250-260 duration and you will be very happy with your performance. Punch your bike to a 1075 with 10.5:1 compression and port your heads for better flow. Do the proper modifications to your carburetors and you will have more power than you will know what to do with. The most expensive part will be buying the pistons and having the cylinders punched. But you do have another option. get a set of used cylinders and pistons on eBay from a 81-82 GPz1100 and drop them right in. You should be able to pick them up between $75- $200 on eBay. I have a spare set of cylinders but not a set of pistons.

9am53 wrote:

otakar wrote:

Now you have the idea. There in fact were three different set of cams. they varied in lift and duration. Most people do not have a method for measuring duration on a set of removed cams. The simplest way to tell is by the part #s you will notice they are not all the same.

Well, actually :blush: I am more confused now! I was going to get some 82 GPz cams and was told that they are basically "J" cams. I got a set of those for free and was told to keep my eyes open for 83-84 cams as they are higher lift.

Anyways, regarding the 1075 pistons question; what would keeping the stock head put my comp up to? would the GPz head then lower it again?

Which 1075 pistons are you talking about. If you buy a new set, get a set matched for your head. The head changed on the 83-85 GPz1100 and so did a lot of other things from the stock J motor.

otakar wrote:

To go to GPz cams in your case would make a nice diference. that is .040 extra lift (1mm) if you go to .400 lift you would increase the lift by 2mm. I went to .420 lift that gave me an extra 2.5mm But I actually decreased my duration to 260* this still gives me very good low end and a very broad power band. To go with more duration makes the engine quite unfriendly in lower rpm ranges and makes it much more difficult to set up your carburetors. I would recommend a good .380-.390 lift cam with 250-260 duration and you will be very happy with your performance. Punch your bike to a 1075 with 10.5:1 compression and port your heads for better flow. Do the proper modifications to your carburetors and you will have more power than you will know what to do with. The most expensive part will be buying the pistons and having the cylinders punched. But you do have another option. get a set of used cylinders and pistons on eBay from a 81-82 GPz1100 and drop them right in. You should be able to pick them up between $75- $200 on eBay. I have a spare set of cylinders but not a set of pistons.

That sounds like a good plan regarding the displacement and porting. I think I would get new pistons and match them to my head (I didn;t realize you could get different tops in a given bore size) I don't mind spending the money to get a streetable workhorse...over time that is.

Now just to un-confuse me regarding the cams: sorry!

my original stock LTD cams were like .320 lift
my new "J" cams are about .340
81-82 GPz are about .340 as well,
83-84 GPz are apparently .375-.380

This is what I got from reading other threads and from the thread I linked above..is this wrong?

OK here is the skinny 81 had .330 lift 82 had .350 lift 83-84 had .380 lift but also about 20* more duration. I do not think that you would want that much duration. This would make the bike very peaky. The late bikes had close to 300* of duration. You want to stay below 260* if possible. I just called a friend of mine who races these things and he had all of the specs. And actually in the 81 the two cams were not identical.

If you wish, I can supply you with a good set of 1100 cylinders which I have a spare set of and you can buy a piston kit from MTC to bore them to 1135 with the correct domes for the head you have. The port work you do on the head will make the most difference in performance. The port work can make more difference than the big bore kit and cams put together. Read my thread, which I gave you a link to on a earlier post. Also check out all of the info on Cavanaugh performance. www.flowbenchtech.com/porting/CRH/kz-data.htm He is the Guru he is the Master he is the Iatola of performance head work. There is not much he does not know about heads.

Cool, thanks for settling that. I read an old review of the 83 GPz11OO and it did say that they were peaky, so much so that the testers had trouble lanching! I aint no motorcycle mag tester, so something that touchy aint my bag! After this discussion I think I will look for an 81-82 1100 block, buy some new pistons, use my J head with some new cams with as you said .380ish lift and medium duration and get Larry to port it. That will be a couple grand...not too much, and as you said give me all the power I need.

Thanks for your patience.

this is what I would recommend for your LTD.
1)Web-Cam #119 grind .384 lift 240 duration.
2)MTC pistons 10.5:1 1135.
3)1100 block.
4)Port cylinder head.
5)Rework your stock carbs to handle new engine.
6)Tie your A** to the seat :laugh:
7)Premium gas (no choice) 10.5:1
8)A very good rear tire (Recommend Avon) :blink:

otakar wrote:

this is what I would recommend for your LTD.
1)Web-Cam #119 grind .384 lift 240 duration.
2)MTC pistons 10.5:1 1135.
3)1100 block.
4)Port cylinder head.
5)Rework your stock carbs to handle new engine.
6)Tie your A** to the seat :laugh:
7)Premium gas (no choice) 10.5:1
8)A very good rear tire (Recommend Avon) :blink:

i didnt even know they made tires,how do they compare with mary kay or that jaclynne smith brand at kmart? :laugh: