1983 GS1100E rebuild advice please

[Guest]

Hey all. I am in the process of rebuilding my 1100e engine and due to some bad scoring in two of the cylinders a rebore will be necessary. As OEM oversize pistons are no longer an option I've bit the bullet an gone with Wiseco 2mm oversize (K1133). In my mind this is a relatively soft upgrade considering some of the performance upgrades I've read about on this forum. But, not having done this before I'm maybe not as knowledgeable as I may have to be which is why I'm deferring to this forum cos there's some pretty savvy people on here thankfully. Together with this upgrade will be a pair of GS1150 camshafts and fueling will be supplied via a set of 36mm slingshot carbs. I guess my first question is whether I need to take into consideration anything else within the engine that would need to be beefed up to accept this change..? Or, is the upgrade so mild that I have nothing to worry about..?

I've read some interesting comments made by RapidRay regarding Wiseco pistons and the need to correctly gap the rings so they don't expand and mess up the cylinders/pistons so I'm aware of that concern. The other area of interest is with regard to the camshafts. I understand that the 1150 camshafts impart a nice performance boost to the 1100. Can I use the original 1150 sprockets and set the timing up as if I were dealing with an 1150 engine, or do I need to get a pair of slotted sprockets in order to re-set the timing..? Any advice as to which angles I should set the timing..?

And last but not least, what can I expect performance wise from all this work..?

Thanks for taking the time to read this and any advice you may care to offer.

[rphillips]

I think mine were Yosh. 2.5 oversized or 74.5mm = 1148cc & don't remember the compression, but still ran on pump gas with no problems. 36mm GS1150 carbs, & "83" mod GS1100 ex. cam. It made a biggg difference. You will need, but not mandatory, slotted sprockets (slot your own with a file or drimmel tool). The GS1150 ex. cam will not have a tach drive, don't know if matters as don't know what you are doing. Will need some kind of a beefed up clutch hub, stock probably won't hold up for long. Been 35 yrs. ago but think I'm still correct. Good luck

[Guest]

Thank you for that info. I must admit I'm quite looking forward to the end of this project so I can fire it up and see how everything has worked out. I'm actually working on converting a 750 Kat frame to take the modded 1100. I will be doing the usual USD front end and changing out the wheels and rear suspension and I'm curious to see how this will all play out. I've had, and still have, Katanas in their original trim since 1986 so I'm used to their geometry and handling but this will be something different. I have all the necessary Katana bodywork and electrics and my plan is to keep the original Kat speedo so the lack of a tach drive won't be an issue.

The Wiseco pistons look pretty normal to me. Just like the OEM, flat topped nothing special. They claim 10.25:1 compression ratio. I don't know what the compression ratio is for the 1100E.

I was also wondering if I would need to go with larger intake and exhaust valves. I'll throw it out there and see what comes back.

I can't get over what a great site this is. The quality of information and advice is fantastic. Once I'm done and am happy with the results then I would like to share the build with pics and specs so that it will join the long list of other like minded folks who have wanted to personalise their ride.

Thanks again.

[rphillips]

Stock GS1100E was 9.5 to 1

[GregT]

Stock valves will do you quite adequately. Dial the 1150 cams in to 106 inlet 108 degrees exhaust lobe centers and you'll have midrange torque for road use.

As has been said, sooner or later the clutch cush drive will give trouble. Check how much movement it has now - if the springs are still tight it's usable at least short term.
There are fixes - and people who do them. Search threads here for some answers.

[rphillips]

Pretty dang close Greg, I remember the #'s well, after a lot of adjusting up & down & back & forth, I wound up with 107 in. & 109 ex. Made it pull like in 4th while in 5th. I remember I was always pulling up on the shifter & back off the throttle just to be sure I was in 5th. Also used the smallest of the restrictors, that came with my V&H pipe that fit in the collector, the smaller restrictor also helped the midrange.

[Guest]

Thank you for that information gentlemen. I was wondering about the valves and if I had to go bigger. It's reassuring for my wallet to read that standard valves will work fine. I'm assuming the extra lift from the cams is sufficient to allow for the increased demands of the engine.
As for the clutch, I had purchased a new clutch basket, springs and friction rings back in 1988, go figure, so when I opened up my dusty old boxes it was like xmas again. I do remember when I was still in the UK with my 1000sz a common repair for the clutch baskets was to drill out the three rivets, install new springs and a washer then put everything back together with beefed up rivets. I still have that basket working without issue in the 1000 today.
At the moment I'm waiting patiently for the Wiseco piston kit to arrive. I'm putting together a short list of parts I will need in order to close up the engine. Can't wait to have the lower cases nicely sealed and ready to drop in the frame. Every day is a day of taking one more small step towards the goal.
I'm not sure if the following question is suited for this particular thread or if I should post it in Electrical / Ignition but with the increased compression pressures, will my OEM ignition system still cope fine or should I be upgrading this too..? Also, and I hope this doesn't sound silly, but will my starter motor find it to be more of an effort to turn against the higher compression. Will this part also need to be more robust..? Just stuff that goes through my head as I work away. Thank you again.

[limeex2]

I believe there is a relay type mod for the starter. It helps the starter clutch. I'm not good at searching but someone will chime in.