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8 to 16 valve conversion

  • Thread starter Thread starter pullerpat
  • Start date Start date
P

pullerpat

Guest
Hi.
I have a 1100 2 valve per cyl and I was wondering if I could swap the top end on it ( juggs,pistons,head ) to convert it to a 4 valve per cyl.
Anyone done this.
thanks
 
Anyone have any reasons why this wouldn't work. If for nothing more than to satisfy my curiosity?
 
mighty13d said:
Anyone have any reasons why this wouldn't work. If for nothing more than to satisfy my curiosity?
Click to expand...

Different oil flow patterns in the two motors. The 16 valve head would be starved for oil.

Hap
 
Well, other than the obvious fact that the heads simply WONT bolt up from the two motors, others have touched on the oil flow channels. Completely different from the two motors. Yes they are both roller bearing cranks, but the 8v is a low pressure system, and I would assume the 16v is a high pressure system. Even barring that fact, you would spend an obscene amount of money figuring out a way to get the two to bolt up, and for that you could BUY a 16v motor in pristine condition.


Secondly, might I ask WHY ON EARTH you would want to do this? The horsepower increase is minimal, I think less than 20HP. Both are great motors, but I have a bit more faith in the durability of the 8v. Not that the 1100 16v is a sloutch (its CERTAINLY NOT the 750 16v hunk of poo) but I just dont see the benefit, even if it were possible, of doing such a conversion.
 
the only reason I asked for a "why" is because he asked IF it can be done and only got a no, not a reason why. So I figured I'd ask for a reason!! lol
 
TheCafeKid said:
Well, other than the obvious fact that the heads simply WONT bolt up from the two motors, others have touched on the oil flow channels. Completely different from the two motors. Yes they are both roller bearing cranks, but the 8v is a low pressure system, and I would assume the 16v is a high pressure system. Even barring that fact, you would spend an obscene amount of money figuring out a way to get the two to bolt up, and for that you could BUY a 16v motor in pristine condition.


Secondly, might I ask WHY ON EARTH you would want to do this? The horsepower increase is minimal, I think less than 20HP. Both are great motors, but I have a bit more faith in the durability of the 8v. Not that the 1100 16v is a sloutch (its CERTAINLY NOT the 750 16v hunk of poo) but I just dont see the benefit, even if it were possible, of doing such a conversion.
Click to expand...
Ride my bike once you'd change your tune!
 
If someone had money $$$$$$$ to burn I guess it could be done. Would need External oil system, Custom hi dollar pistons, and a good machinist
 
Good to know, I thought the 16 valve 1100 was low pressure & the 750's were the higher pressure. I know you could put the 750 oil pump gears in the 1100, to give it more volume.
 
rphillips said:
Good to know, I thought the 16 valve 1100 was low pressure & the 750's were the higher pressure. I know you could put the 750 oil pump gears in the 1100, to give it more volume.
Click to expand...

You are right, the 16 valve 1100 and the 8 valve 750 are low pressure & the 16 valve 750's are the "high" pressure. The reason is the type of bearings used on the crank. The 1100/1150/8V 750 use roller bearings and the 16V 750 uses plain bearing shells. One of the few items that are the same and have the same part number between the 8-valve and the '80-'83 16-valve 750 motors are the oil pump gears. The 1100/1150 has different stock oil pump gears, resulting in a slower turning oil pump. The addition of the 750 gears to the 1100/1150 oil pump results in the pump turning faster (not a whole lot, something like 15% to 20% faster, as I recall) but due to the nature of the low pressure system the result is that you get greater volume but not a significant increase in oil pressure.

I think the 16 valve 750 motor is an excellent engine. VERY smooth especially when compared to the 1100/1150. Not a hot rod but an excellent long distance motor.


Hap
 
Last edited:
I have no personal experience regarding the differences between the 750 and 1100 but in support of Hap post, I'm a HUGE fan of smooth engines. All these bikes have surplus power so the quality of the power is what matters to me. Love the 850 for that reason; engine is butter smooth at normal cruising speeds. More power would be fun, but not as useful in my world if more vibration went along with it.
 
the only reason i aksed about the 750 was that i picked one up cheap the other day. the mounts look the same but would have to change the clutch set up for the newer motor. my 77 has low compression and was just trying the save the cost of a rebuild. looks like i'll just have to pony up the cash. whats a good price on a valve job for a 8v? or should i just clean the head and change valve springs, lap the valves and reassemble? bike has 36,000 miles.
 
heathen said:
the only reason i aksed about the 750 was that i picked one up cheap the other day. the mounts look the same but would have to change the clutch set up for the newer motor. my 77 has low compression and was just trying the save the cost of a rebuild. looks like i'll just have to pony up the cash. whats a good price on a valve job for a 8v? or should i just clean the head and change valve springs, lap the valves and reassemble? bike has 36,000 miles.
Click to expand...
Compression issues stem not only from the valves, but also the piston rings. If you have a decent set of tools, and access to a ball hone (or a stick hone will work too) you can do a rebuild yourself. If youve any mechanical experience, its really NOT that difficult, and everyone here can help guide you thru it. A manual, especially a SUZUKI shop manual is ESPECIALLY helpfull. I had never done it either, but that manual basicly saved my life. Ive done and helped to a couple of them now. The only thing you'd really need to do if you so desired, is have the head machined where it meets the jugs to assure a good level seal. But, with that low amount of miles on it, if it looks pretty straight and level, you might get by without it. Steve from the board here just put up a nice VIDEO tutorial on replacing the valves. You can even MAKE your own valve spring compressor CHEAP and he tells you how. Just get all your parts together first, and take a day off from work, and hit it hard, you can probably get it done in one day. You'll need a gasket kit, valve seals, piston rings and your tools, and thats pretty much it!
 
heathen said:
the only reason i aksed about the 750 was that i picked one up cheap the other day. the mounts look the same but would have to change the clutch set up for the newer motor. my 77 has low compression and was just trying the save the cost of a rebuild. looks like i'll just have to pony up the cash. whats a good price on a valve job for a 8v? or should i just clean the head and change valve springs, lap the valves and reassemble? bike has 36,000 miles.
Click to expand...

Just clean the head and lap the valves. I doubt your valve springs are bad with that few miles. I suggest you do a compression test on all four cylinders when the motor is cold. Pull all the sparkplugs then run a test on each cylinder. If one of the cylinders is very low, pour about a tablespoon of heavy oil (40W or heavier is best - not 10W-40) into the sparkplug hole then immediately run a compression test on that cylinder. If it increases a great deal then you have bad rings or excessively worn cylinder, or both. If nothing changes or it changes very little then you probably have a valve problem.

Hap
 
i am going to do the wet test tomorrow. am going to do the rings but thought id do the head while its off. i down loaded the service manual it will help. have built many race car engines so don't think this will be to hard. hey i'm already ahead of the game this thing is missing 4 cylinders (lol). i am going to start on it sunday. not in a hurry will take about a week i figure. of course that is if my son will stop breaking his racecar.
 
I agree with Hap, didnt read the post thoroughly, your valve SPRINGS should be just fine. Before you take your head apart tho, you may want to inventory your valve shims, just so you know where your starting point will be when you put it back together. After you get it back together, i would suggest double checking your clearances, likely they may change. Seals, rings, lap and MAYBE have the head machined if you think it needs it. You sound like you know motors well enough, this one will prove nice and simple. And actually, quite fun. I dont worry bout the top end of my 8v motors, but Ive never split the cases, and really, i dont want too..lol
 
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