Tell me I am nuts or not.

[dardoonk]

So, first, a long time away from the GS world as a now 2.5yr old son makes me appreciate time on a bike rather than playing in the garage. I think though, I am at the point of a well deserved project - one that I basically shelved a couple years back. The past few years, I've managed to acquire most of what I need to build a new motor for what is currently a 77 GS750. My plan is to build a big motor & keep it one piece.. Basically, it would be akin to a muscle car that never really gets pushed to the limit. It will be fun to build, ride and have - it wouldn't be raced.
Here is what I have today:
2 - 90% complete GS1000 motors - torn down and both cases are in fine shape. (all the stock parts for both).
3 - stock trannys - I presume I should back cut 2nd gear on the one I use.
1 - 1100G block and pistons (stock) - I don't expect to use
1 - Vance & Hines ported/ polished 8V head with all the goodies - shim under buckets, oversize valves, springs, & what appear to be titanium retainers. - It's in nice shape.
1 - set of Andrews S2 cams (I need cam sprockets & a new chain)
1 - JE piston kit that shows no use & a re-sleeved 1100 block they came with - The pistons measure 78mm. The sleeves measure 81mm - so I am working on thin ice.
I've also got any parts, such as the oil pump, from my 750 engine.

I spoke to Cometic and confirmed they can provide copper gaskets for both the block & head. On request, they will blank the oil passages on the head, which I presume would make sense as I expect to fashion some external oiling. So, my list of questions & what I think I need (aside from a slap alongside my head for even bothering)
1] Weld the crank - my question is who (Pierson & Gardner are the two I know of) - What will this set me back just to confirm it is straight & weld it?
2] Clutch basket - I have two stock ones - probably, I should weld one, but is there another option (maybe a stronger stock clutch from something else), even if it requires changing the output on the crank?
3] I see APE still offers new cyl head studs for this motor, but I cannot find main studs. Will 16V studs work?
4] Clearance on the case - This is the biggie -- I have to shove 81mm sleeves thru the case and there isn't going to be much left. I haven't measured closely, but it looks like the sleeve will extend into the area holding the stud. Since the bottom of the piston doesn't come near the bottom of the sleeve, logic tells me some of the sleeve can be removed. Logic also tells me they are that long for a reason.. Help me here!
5] What's it going to take to fuel this thing? My thoughts now are that I need to start with the smallest carbs I can get properly jet because the high flow thru the head will be a challenge at lower revs on the street.
6] If I keep it around 9.5 - 10 compression, what kind of HP am I looking at?
7] Can I keep this thing from leaking like a sieve?

Am I nuts for bothering?

Thanks, guys.

[blowerbike]

pearson is in ohio and does cranks and baskets and trans(back cut all gears). 937-839-9723(John Pearson)
ok i'm off to bed.
i'll try and help tomorrow.

[simon kuether]

Hey Kurt , I think you're nuts , but building this bike has nothing to do with it .
We've still got the T-shirts .

Go the nutters .

Cheers , Simon & Deb

[trippivot]

ok here is the deal. you can do this. you have to custom match a couple things to make it work**. in my experience 145hp is almost maximum 160 possibly.

upper case half and lower cylinder sleeves have to mate and match. **

instead of lower stud kit replace with 8.8 or harder flange bolts. stock oil pump oiling system and stock trans is fine as - is.

put a modified basket and HD backing plate on your matching crank/clutch gear. Pearson crank work $5~7 hundo's **

85 or 87 pump gas will work fine at 10.5/1 set of 34 or 36 mm CV's will be pleasant to ride you got a lot to worry about before looking for VM33 smoothies.


glue it as much as you want to after some heat cycles it is going to leak.

yes you are nuts for wanting to push the limits. remember trippivot says modified bikes equal modified problems.

I went to the edge of gs1000 , somewhere around 1300cc / 10,500 rpm started sawing themselves in half - and now you are just getting interested. cool.

FIRST buy a new camchain, mate the cylinders to the cases, get crank and clutch beefed up, you can do many different things after those basics are mated.

-- 1105cc was a great reliable combination to put a big head on
you have a lot of work to do

[blowerbike]

5-7 hundo to weld crank........come onnnnnn...lol

[BadBillyB]

Hey Kurt, been near 4 years since we last talked. This could be an interesting build and I hoped I could offer some help/advise. Can you post some pics of the pistons you are going to use??....I have never seen low compression 1238 pistons before. What size valves are in the VHR head????....Is it a small port head or a large port????.....The intake boots are completely different and may influence what size carbs to use. A stock clutch basket will be fine as long as you use the HD backing plate and springs. I suggest carefully inspecting both baskets before selecting the one to use. Besides a visual inspection for clutch plate wear in the grooves of the basket, also check it for wear that you cant see with your eye. With the basket on the work bench (gear facing up), use two large screwdrivers placed between the gears inside edge and the backing plate edge, twist the screwdrivers left and right checking for play between the gear and basket. If its not tight, its no good.....Call Jay at APE and see if he can supply you with a custom set of case studs, he did it for me many years ago. I think most of the 1100 4V studs are the same. Don't use a copper base gasket, use an OEM gasket and enlarge the sleeve holes with a razor. After having been down this road already, I wished I had the bottom of the cylinder sleeves turned down before boring the upper case. If you use HD cylinder studs, don't tap the holes in the case before installing them, just install them and do not over tighten them. As far as the transmission goes, under cut all the gears, unless they look perfect. For low compression motors, I would think a MLS head gasket would be preferred and seal better. By the way, member NickP bought my complete drag bike and had it shipped to the UK. He is building a 1327cc motor to go in my old chassis. He is using my old head and big block, you can see it here under "latest news"....Billy http://www.suzukiperformancespares.co.uk/

[trippivot]

5-7 hundo to weld crank........come onnnnnn...lol

would you like me to scan the receipt I have from last year? --

[blowerbike]

he asked about welding only...

[trippivot]

big port or small you are going to use Kawasaki J model carb insulators 11060-1135 and oval out the mounting holes to fit. - sm ports make better useable power.

1238 cc' size is also a Kawasaki piston from later model gpz1100 1984 -- too big -- that is a grenade in the making - a lot of custom work and cases thin as Reynolds wrap.

not good return for the money you are going to invest - consider an external case girdle . ask what the heck is that ?. the guys that made your head will have the specs. maybe. since 1980 was a long time ago..


if you just zap the crank throws with a reference rod-- my advice ? - start with a 1105. enjoy it- if you need an exotic 1238 monster you may not want to know how it is going to end nor how quickly..


#1 any of the 4 small con rod end is going to sever. #2 the whole left side of the crank is going to saw itself out of your frame.-

[trippivot]

he asked about welding only...

he does fully disassemble and inspect what you send him first - would you be the type of person to ask him to only weld a crank that has core problems? his reputation has been earned for "good work" .

if you are looking for cheap - tig it at the local lawnmower shop --- 1238 is going to be too much for the helical gears anyway - so tack another $1500 to the build.

or let it go boom .

[BadBillyB]

he does fully disassemble and inspect what you send him first - would you be the type of person to ask him to only weld a crank that has core problems? his reputation has been earned for "good work" .

if you are looking for cheap - tig it at the local lawnmower shop --- 1238 is going to be too much for the helical gears anyway - so tack another $1500 to the build.

or let it go boom .

He is apparently building a low compression motor for the street. That said, there will be way less "hammering" on the small rods that come with the GS1000 crank. He will be lucky to approach 125 HP with his intended set up. I hear what your saying about sawing crankshafts in half, I have done a few myself. But this was done on high compression/high lift cams. He has 390" lift cams which barely require under bucket shims. I do not dought your expertise Trip but as he stated this is not going to be raced........Billy

[blowerbike]

if you ask for a weld....you get a weld if he deems it ok from an external inspection.
no other warranties implied.
it's crazy to spend spend big money on a 1000 engine...stuff an 1150 engine in and make similar HP as a hot rodded 8 valve.

[BadBillyB]

Clutch basket inspection

Here is a good video demonstrating how I tried to described on how to inspect the clutch basket you may select to use.......Billy

https://www.youtube.com/watch?v=DF45mwGnLAY

[dardoonk]

[QUOTE=trippivot;2153327]

glue it as much as you want to after some heat cycles/QUOTE]
help me out on the glue part. I'm not familiar.

Trip, your first post seemed pretty positive, by the time I read your later ones, I wanted to hurt myself.... did you mean a 1238 is a grenade, or a 1238 KAWASAKI is a grenade?

I am out of town till Friday, but will get some pics of the head & pistons after I get home. I am pretty sure it's large ports, but if it was small, it defiantly isn't now. The pistons & block came as a set. I assumed they were GS specific, but I suppose they could have been KZ parts. Ether way, they don't look like they are near as high compression as the Wiseco or Murawaki pistons for my KZ. This is why I estimated they are lower compression.

Cometic told me copper is my only option for the head gasket. Not enough clearance for their MLS. Is there another source?

Do my liners need to extend much past the lowest point on the piston when at BDC?

[dardoonk]

if you ask for a weld....you get a weld if he deems it ok from an external inspection.
no other warranties implied.
it's crazy to spend spend big money on a 1000 engine...stuff an 1150 engine in and make similar HP as a hot rodded 8 valve.

Blower, you almost had me convinced a couple years ago, but this isn't really about the HP. ��