Setting the timing properly

[Suzukian]

I suggested gasket as a measurement tool, (and also a viable a fix, as it would work, it's been done before), in reality they do not crush as much as you seem to imply. Better than aluminum, would be to make a Copper gasket. You can reheat those and use them over. I would do anything except grind the inside of the combustion chamber head. Unless you have a milling machine and can make a form tool to get the exact same combustion shape, the motor will be a mess. There was another thread on this forum here the poster was worried about head gasket compression and was shocked that it only compressed something around .01 to .015" of an inch. These gaskets to do not compress that much, they just compressed enough to seal, but that's it. A Copper base gasket can have pressure ridges formed to help in sealing it, and that gasket will compress only so much. That's why a sealer like Yamabond # 4 works so well. That will further seal the surface, while that gasket takes off the shape. There are no gases down there, you're sealing oil, and crankcase pressure. I don't think taking off a millimeter will affect that strength of the piston at that part of it. That work would be best done only a lathe or milling machine, where you can reproduce what you have done consistently. If isn't done right, will be hard to sync, as what would be the proper syncing where each combustion chamber is slightly different? The engine will be lumpy and never make you satisfied. You'll end up hating the effort you put into it.I don't have a horse in this race, I just don't want to see you make some fundamental errors that will come back and there's nothing worse than putting a motor together and realizing that something you did halfway through the build wasted your time, and money. At this point, if you can make a bike that runs strong, you'll be ahead of the game. IMHO.

[timebombprod]

i mean its either go back to stock which i will not be satisfied with or do some sort of machining to get these pistons to work.

i could take out part of the pistons but since these are already aftermarket and we haven't had somebody really put them to the test, that could really make them a weakspot.

the reason im thinking about the cylinder head is because the guy that has been helping me was talking about that, id only be doing a little at a time to ensure im not taking out to much or misshape it, it seems like everyone but him is saying not to do that but as far as i can tell itd probably be the best way to go through with this kit, if im honest im not too worried if i screw it up, i mean ive learned so much from this bike and the help from everyone that i could just find another solution to get this motor going well, or just put a whole different motor in the frame.

if i go through with the dremmeling itll probably be tonight, ill talk it through with him, i mean he builds dragbikes and has had plenty of experience doing these things, i know that doesnt mean i do and i wont be as good as him but if i never do, ill never get better at it.

this bike has honestly been more of a learning experience than a bike, and as far as im concerned ive learned more than i ever could off of this bike than i ever thought.

i basically know everything there is to know about diagnosing and fixing and tearing apart/ rebuilding on this particular model, so much that anything ive worked on bike, boat, whatever has been nothing but a success. the next step is modification, if i screw up oh well, it takes me doing one annual service on somebodies boat to get 3 cylinder heads for this bike.

[zed1015]

i mean its either go back to stock which i will not be satisfied with or do some sort of machining to get these pistons to work.

i could take out part of the pistons but since these are already aftermarket and we haven't had somebody really put them to the test, that could really make them a weakspot.

the reason im thinking about the cylinder head is because the guy that has been helping me was talking about that, id only be doing a little at a time to ensure im not taking out to much or misshape it, it seems like everyone but him is saying not to do that but as far as i can tell itd probably be the best way to go through with this kit, if im honest im not too worried if i screw it up, i mean ive learned so much from this bike and the help from everyone that i could just find another solution to get this motor going well, or just put a whole different motor in the frame.

if i go through with the dremmeling itll probably be tonight, ill talk it through with him, i mean he builds dragbikes and has had plenty of experience doing these things, i know that doesnt mean i do and i wont be as good as him but if i never do, ill never get better at it.

I've been building race engines, drag bikes and much more for over 40 years and i'm not saying you should stop what you are doing but you need to understand what you are doing and go about it correctly otherwise there's no learning involved.
I would be wary of altering those cast pistons, especially on the sides of the crowns as there's likely to be insufficient material that can safely removed so keep away from them.
There's probably some scope for modifying their valve pockets but then again you need to MEASURE the crown thickness in that area to be sure.
If i HAD to make this work i would modify the combustion chambers to suit the pistons ( which I have NOT said not to do ) but again you need to make the correct calculations to work out what volume you really need before removing material from the appropriate areas and not just blindly going at it with a dremel or whatever you have.
You will learn much more following a planned approach rather than winging it and your "drag bike guy" isn't helping by giving you only part of the story IF that's really the case.

I've already stated previously the correct start point to establish base measurements but you seem to have ignored anything i've said and still persist on wanting a quick short cut solution .
Even if you just start taking meat out of the combustion chamber you have to ensure each chamber has the same volume as the rest and the correct volume to achieve the required compression ratio.
Do you know how to CC the chambers as that is the LEAST you need to know for what you intend to do.

[Suzukian]

I don't know why you think taking some off the pistons will weaken them. Pistons are designed with extremely thick tops. That's where you are expected to take stock off for interference issues. If you don't have the machinery to do this though, like a lathe (with milling attachment), or milling machine, you won't be able to match the pistons and will end up with a pile of parts. It might even run, but not as good as it did stock. Consistency is key, as is knowing with what your working with. From your statements, i would advise bringing this to someone who can fit the cylinders to give you the clearance you need. It if's a money issue, save your money till you can send it out. Better to wait the waste your engine. (MHO

[timebombprod]

Okay so, here is what I am doing.

I understand that im not doing it as proper as I could be by any means, but I'm still gonna do it, my ignorance is probably the best way I learn things.

okay so how I am doing it is right now I'm using playdoh and putting on the piston heads, getting the pistons to touch the combustion chamber and dremmeling out the areas that show to interfere on the pistons, its a very slow process with the dremmel so i dont have too much worries about overdoing it.

How will I know there's enough space? Well first I'm going off just by checking for interference without the headgasket, once there is no interference without the gasket I will know that there is atleast a mm of space between the piston and chamber in the areas I have had to take out, next i will have the head sitting upside down with the spark plugs in, and fill the chamber with 20cc of water, and then place the pistons ontop of them seeing if any water comes out, if it does I know I am shy of the amount of volume needed in the chamber.

These methods will be questioned along the way from my friend making sure I'm doing it the right way, and so far things have been going on fine, and I think I found a rough draft of making valve paste lol, oil and aluminum dust!

[zed1015]

Save yourself a lot of time.
Space the head so it clears the piston then clay the head with a non springy compound that won't decompress slightly and give false readings when the pressure is released.
Playdoh isn't really suitable.
Oil the head and piston so the "clay" doesn't stick.
Once done you will be able to carefully section the clay plug and measure the high and low areas and identify where and how much needs removing.
Doing it this way vastly reduces the amount of times you will have to refit and remove the head.
Once you have the head sitting on the gasket with no piston to head interference you can take a final clay to check valve to piston clearance and confirm you have 40 thou at the closest point and then cc the chambers to match them and get the correct volumes.

[allojohn]

Unsubscribed - this thread is giving me the heebie jeebies...

[Who Dat?]

You think that somebody should mention to him that he simply has the wrong pistons?

Nah, let him learn his own way.

[timebombprod]

Update, I think I have one single cylinder done, gonna have to work on the other one in the same crank rotation to make sure it is, the amount of metal I have to take out is pretty wild, I even have to take some out around the valve on the surface of the head.

I'll put it this way, if the valve ends up hitting or a spark plug interferes after I can ensure that the combustion chamber doesn't touch, imma f#$##$ sue lmao. Also if that happens I'm just gonna make this bike chain drive and throw a gsxr motor in it.

I think everyone knows but don't ever buy this kit unless you have a 65mm cylinder with a dome shaped chamber. I'm gonna end up making a actual thread showing all the work that had to be put in for these to work, and I'll end up leaving a review for the kit to stop anyone from getting these.

What would i have done differently if i knew this from the beginning.....either slap a gsx1100 shaft drive motor in the frame or make it chaindrive and slap a gsxr motor in it and call it a day.

[rphillips]

Good thought, most GS750, GS1000, and GS1100 chain dr's were a pretty easy swap. And I think GS850 shaft to GS1000 shaft and GS1100 shafts would work. It'd be interesting to know about a swap from a GS650G to a GSX1100G eng., That would be a "HOOT"

[timebombprod]

Good thought, most GS750, GS1000, and GS1100 chain dr's were a pretty easy swap. And I think GS850 shaft to GS1000 shaft and GS1100 shafts would work. It'd be interesting to know about a swap from a GS650G to a GSX1100G eng., That would be a "HOOT"

I think it'll be much more manageable than getting these pistons to work, but I'm gonna go ahead and see it the whole way through.

Also, I found the kit for $60 on a website......I paid close to $200......the item is no longer available on their ebay so i cant leave a review.

[timebombprod]

Okay well I'm definitely going through with this kit, 1 and 4 are done but they are not done smoothly, will either smooth it out or weld some metal on them and refine to get a better shape. I actually found a method to this madness for 2 and 3 and they should come out alot better.

I even made a video for this kit as I will basically be a pioneer of getting this kit to work if somebody goes as far as I did without realizing that these pistons are definitely not meant for this bike without serious modifying.

[timebombprod]

just an update, i thought i was finshed the other day because i was able to get the right amount of clearance on all cylinders for there to be a mm of space between the piston and chamber at its closest point with the headgasket, but i put 20cc of water in the chambers and put the piston in place where it would be at TDC and plenty of water came out, so you literally have to take out all the meat you can lol.

ill have before and after pictures of the chambers showing how much had to be done. if the bike blows up (hopefully on the top end) ill either do some type of motor and/or drive swap or some type of top end swap/ modification that will be a lot better and not pushing tolerances so close. i also picked up another bike, there will be an update for that, not something most people in here might like, but i love it.