82 GS1100 Conversion to GS1150 ???

[Anonymous]

I found out that my old GS1100e engine was a complete mess and bought a GS1150 bottom complete with crankshaft and gearbox. I'm reboring my GS1100 cylinder up to standard 1135cc pistons and using the old top. I have bought a new V&H Megaphone.

Qustions:

1. Do I need to replace my BS34 standard Mikuni Carbs?
2. If not, how should they be jetted?
3. If yes, what type should I look for.
4. Will I have to get other Camshafts?
5. Will I have to change some of the ignition parts?
6. Do I have to take other things into consideration?

What I am looking for is a really good bottom end performance. (ehh better than before...he)

Thanks
Houge

 

[cbxchris]

I hope you noticed the 1100 engine used 18 mm pins and the 1150 used 20mm pins! 8O

 

[Anonymous]

As CBXChris says: The pistonpins are 20mm. So be sure to get the right pistons. And why not go for 1168cc while you?re at it? Doesnt cost more and is the maximum bore for the 1100 sleeves. Just put everything on, the bike should work fine, maybe a re-jetting with the increased comp.ratio is in place.
If you have 18mm pin-pistons you can put bronze-bushings in the rods to get 18mm, but that means you must have the crank out of the block.

 

[Anonymous]

Thank you for the reply's.

I found out about the pins :? And wanted to buy a pistonkit. But I don't think there is any 1168 kits with 20mm pins. The kits with 20mm pins are a larger bore, and then I need new sleeves as well. A pistonkit is very expensive here in Denmark 830 USD 8O !!! So I figured to go for the stock 1135 pistons, I found them at Bruce Van Sant 15 $ ea.
http:\\www.dragbikeparts.com
Do's anybody know that guy?

I have the stock 1075cc pistons in good shape, but my cylinder is torn( 150.000 km) don't know how to convert to miles!!! So I do need a rebore.

 

[cbxchris]

Another cheap mod would be to use the 1150 camshafts! To bad you couldn`t come up with 1150 cylinder....couple on ebay now. You an go as large a 1198 or so with no problem. Check the clutch hub out very good...backing plate is bad to EXPLODE when abused. Stay away from 750 gears for added oil pressure...they cause more problems than they are worth.

 

[Anonymous]

Another cheap mod would be to use the 1150 camshafts! To bad you couldn`t come up with 1150 cylinder....couple on ebay now. You an go as large a 1198 or so with no problem. Check the clutch hub out very good...backing plate is bad to EXPLODE when abused. Stay away from 750 gears for added oil pressure...they cause more problems than they are worth.

I hope you have some information to back up your statement about 750 oil pump gears. Ther are a few dozen folks who will enjoy learning about that.

 

[Anonymous]

I`m also interested in hearing about those problems with 750 oil gears, I thought that it`s a "must" thing to do in hopped up engines??? So enlighten us please.

 

[Anonymous]

I was just thinking that since 1166-68c cis the max overbore for stock gs1100 jugs and i think that 1196 it the max for the 1150 jugs that the top wont fit the lower end without special machine work. Not sure though.

 

[cbxchris]

I have seen numerous 750 gears with the teeth completely sheared off. I will admit most were at the drag strip and with modified engines. I never needed or ever had any top end problems or turbo problems with a mid 7 second GS. I do not think you need those gears unless you are running some very large camshafts. The best thing you can use is a top end oiling kit from Carolina Cycle...they have the best kit ...period. On a stock top end (stock cams and springs) I wouldn`t use anything at all. Jay at MRE is good friends with Kim at CC...he can get you a oiling kit if ya need it. :lol:

 

[Hap Call]

I have seen numerous 750 gears with the teeth completely sheared off. I will admit most were at the drag strip and with modified engines. I never needed or ever had any top end problems or turbo problems with a mid 7 second GS. I do not think you need those gears unless you are running some very large camshafts. The best thing you can use is a top end oiling kit from Carolina Cycle...they have the best kit ...period. On a stock top end (stock cams and springs) I wouldn`t use anything at all. Jay at MRE is good friends with Kim at CC...he can get you a oiling kit if ya need it. :lol:

While I agree that the top end kit is a good move, I disagree on the oil gears. The top end oiler is used in three cases: 1.) If you have over sized cylinder studs which would restrict flow up to the heads or 2.) if you have high lift cams or 3.) a combination of both. If you use the top end oiler kit with out the larger studs you will now have less restriction in the oil system, thus lowering your overall pressure, which is already very low especially if the oil is hot. But putting the gears in there you increase your flow and offset to some degree the loss of oil pressure.

The oil pumps on the GS1100 and the GS750 are the same...even the same part number. When you put the 750 gears in the 1100 you increase the oil pump speed by 12% (I believe that is what I came up with when I calculated it)...not a whole lot but it does help.

As far as sheared teeth I cannot recall a lot of those. Greg Cope and Byron Hines both use 750 gears in the motors they build...their motors seem to last.

Hap

 

[cbxchris]

I ran much bigger studs in my engines than APE`s. I also had my heads milled and used gsxr head orings around the oil galley`s...no more oil leaks. I still stand by what I said....seen lots of gears sheared off. I`ll add this also...lots of people were experimenting for a while with the gear off a 750 hub ...that didn`t help. But the fact is I and almost everyone I knew and that was a lot quit using them.

 

[Anonymous]

are you talking about the straight cut gear for the outer clutch hub that came from the 750???

 

[skip]

I was just thinking that since 1166-68c cis the max overbore for stock gs1100 jugs and i think that 1196 it the max for the 1150 jugs that the top wont fit the lower end without special machine work. Not sure though.

scotty 1230 is the max for the 1150 without boring the cases

 

[Hap Call]

I ran much bigger studs in my engines than APE`s. I also had my heads milled and used gsxr head orings around the oil galley`s...no more oil leaks. I still stand by what I said....seen lots of gears sheared off. I`ll add this also...lots of people were experimenting for a while with the gear off a 750 hub ...that didn`t help. But the fact is I and almost everyone I knew and that was a lot quit using them.

Did anyone you know do a failure analysis? The teeth shearing off could be the result of something else, like the straight cut gear, or maybe some other issue...with the two companies that have the best record building motors using them (I don't know if Star uses then or not), they must have found out what was causing the gear failure. Gear teeth shearing is normally caused by locking up of a component, non-axial loading (if anything the 750 straight cut gear would help prevent this), or poor metallurgy. I have not see the failures that you mention.

We will just agree to disagree on this one...how does that sound? :wink:

Hap

 

[Anonymous]

So are you talking now about oil pump gears or primary gears on crank and clutch?? Why the 750 oil gears are any weaker than 1100? Aren`t they same metal or what? I don`t think that size change could cause breakdown...I haven`t heard any problem with these. I use the original Suzuki parts from 750 in 1150.

 

[Hap Call]

are you talking about the straight cut gear for the outer clutch hub that came from the 750???

Yes...but you also have to have the straight cut gear on the crank. Straight cut gears are also called spur gears. They put the spur gears on the 750 because it is a less expensive gear to produce. The 1100 get the helical gears for a couple of reasons. One is that the teeth are longer, thus stronger. Greater surface contact allows them to carry larger loads, and they are quieter than spur gears.

The reason a lot if racers go with the straight cut gears is that there are two advantages that the spur cut gears offer - they are more efficient and they do not have a thrust vector, or force that moves parallel to the transmission input shaft, which in turn places stresses on the clutch basket and transmission.

The best gear would be a herringbone gear which when viewed on end looks like two helical put together forming a stack of "V"s on the gear. It has both the strength of the helical and the ability to counter the thrust vector. It is also VERY expensive and is not as efficient as the either the spur or the helical gear and takes up more space than either, which is critical in small engines.


Did that help?

Hap

 

[Anonymous]

its what i was trying to expose Hap Thanks for doing the work as you are always so willing to do for all of us.
Dom
I never knew about the V shaped gear though

 

[Anonymous]

I once thought changing the gears to straight cuts, but with my modest hp output it isn`t necessary. My friend who was European champion with turbocharged 1150 drag bike (over 450hp) said that after 200hp the helical gears are self exploding grenades inside the engine, which indeed destroys everything when that happens... 8O Do you anyone has had such explosions? I think there are few...I changed the backplate and springs immediately to stronger ones.

 

[Hap Call]

I once thought changing the gears to straight cuts, but with my modest hp output it isn`t necessary. My friend who was European champion with turbocharged 1150 drag bike (over 450hp) said that after 200hp the helical gears are self exploding grenades inside the engine, which indeed destroys everything when that happens... 8O Do you anyone has had such explosions? I think there are few...I changed the backplate and springs immediately to stronger ones.

You are right about the problems after 200HP...that is a result of the angle of the teeth meshing on the two gears that cause a thrust vector force that is perpendicular to the gear...BANG! the gear comes apart because it was not designed for this force. The straight cut gear does not have this angular mesh of the teeth thus it reduces the chance of this happening.

Hap

 

[cbxchris]

I agree that straight cut gears are needed in drag racing and for the street guy that is extremely rough on his bike. On one of my 1150`s I`m thinking of a small overbore and possibly larger valves on the stock seats. Then possibly a 355 lift cam or so. I do not think I will need straight cut gears for this. I`ve already got 2 heavy hubs here now for both bikes. I guess on the 750 gear issue I`ll agree to disagree also. I`m just scared of them from what I`ve seen happen. When this was happening was late 80`s and early 90`s. APE had also made some overdrive oil gears that had a bad reputation for trouble. I guess I may have to rethink when I do a engine when my back recovers...I like for them rockers to live!! After screwing with shim motors for the last several years these rockers are a dream!!!