1198 OVERBORE $150.00 Kit

[ViperRon]

I got the 1198 kit back early in the year. At the time I had rebuilt the top part of the bike and was running good. After a hard run with some friends I started noticing a different sound in the head was not a valve or a rod noise but after a while I assumed it was skirt slap of the pistons. In the beginning I only could only get second oversize rings and trim to fit but the cylinders needed oversize pistons.

I took a spare cylinder assembly I got from Andreas to a great shop high quality and they bored the cylinders.

The final bore was 2.9330 in and that left a .0016 skirt clearance the ring gap came out to a very tight .009.

You have to be careful when doing the bore of the lower unsupported part of the cylinder as it heats and could easily egg shape if you do a deep cut. When finished the taper on the bottom of cylinder will be gone and need to be re-cut. My machinist used his high-speed hone to do the final on the cylinders and it had a very fine crosshatch pattern.


I rode the bike to the Southeast meet in September but because of other issues did not get to balance carbs before trip. I did balance them there. Bike run great entire trip. On the way back I checked mileage and was getting very near 40 mpg running between 75 and 80. I have full fairing and bags so I think that is pretty good. Carbs are factory except mains are 120 all the way across no mods to air box standard air filter Mac exhaust with baffles I made for the mufflers. I could probably run leaner but I'd just have blue pipes and boiling oil with very little gas miliage gain.

The only condition I noticed I did not see before was the main seal on the left ignition side started leaking between the seal and motor. The leak was pretty good by the time I got home from the 500 mile trip down rally and return about 1500 miles I leaked about ¾ quart.

First seal I ordered the Yamaha seal part number off Ebay seal that came was not correct size so I tried to get one from Advance Auto using the SKF 12735 as a cross. I had to really drive it in and I used sealant. After a short time I noticed it leaking. Seems it was too tight and where it contacted the shaft at the bottom it allowed oil to leak.

Got new seal off Ebay Federal Mogul automotive #223240 cleaned and put it in with Permatex red high temp sealant and so far is sealed good. Not sure if the overbore kit had anything to do with it but have heard that others had a leak there after an overbore.

Bike runs great feels a little more peppy but mainly the engine is quiet and smooth. One thing that is a little issue is cold compression is between 178 and 181 and when you have run it and engine is hot the AGM high amp battery even has a hard time cranking it over.

Get a good shop to do yours and get a new battery and it’s the best fix for the money if you have to redo cylinders. I would not advise just doing it for power.

[skids]

Good follow-up report Rodan!

[trbig]

Just for comparison, Wiseco uses a .0020 clearance and a .008 ring gap.

Yes, a good shop should know better than to do a deep cut, but it's not so much because of egg shaping, it's because as the bit cuts, it gets hot. As it gets hot, it expands and cuts deeper, so if you go to someone who is in a hurry or doesn't know what they're doing, you'll end up with a proper clearance at the top of the cylinder and larger, looser clearances at the bottom, helping promote piston slap. If you have them bevel or chamfer the bottom of each cylinder, it helps IMMENSELY with reinstallation of pistons/rings

So you said you replaced the pistons, but did you replace the crank bearings and the conrod bearings as well? I just can't imagine doing all this to a motor and not replacing those.. at least the crank bearings, and putting in new crank seals.


P.S. I didn't think there'd be a problem with that cheaper kit. Many had a problem with those pistons being cast, versus Wiseco's forged pistons. The stock pistons are cast and do just fine. I would like to see the comparison between the stock piston domes versus this new set. Wiseco's piston domes fall in between the flatter 78-79 pistons and the later higher domed pistons.

[trbig]

Also, for the crank seals, I've had really good luck with these. Try to find a TCM seal supplier to get them. I ordered a half dozen of each last time, but these are a double lipped seal, so you have two sealing lips sliding on the crank versus the normal single. It also assures that the lip that is riding on a new spot. The old seal can wear a groove on the crank when grit gets to it and rides in that exact spot year after year.

[TopCatGr58]

Hey Ron,

Thanks for the update on the "cheap" 1196 bore kit! Remember folks, it's still ~$50.00 a hole for boring!

Tod....I, too, did the smaller (1179) wiseco bore kit on mine with an estimated 50K miles on the lower end....and did NOT split the cases or replace rod/crank bearings! In my thoughts, these engines were overbuilt to last 100K+ miles.
I had had my bike since new, 17 miles, but odometer broke at ~900 miles, never fixed it the 9 years I rode it before it died, that's why the estimated mileage. And as we thought, they(overbore kits) do not necessarily provide much of an increase in power, hence, not much more "STRESS" on the bearings vs. OEM, and with the rarity and $$ of the crank bearings, it was working great before the teardown, didn't expect it to behave any different afterwards.

Perhaps this was Ron's thinking also, not sure, but since "we" are a frugal bunch, if it's not broken, we don't necessarily fix it. Lots of folks acquire these bikes with much less mileage on them, but may have been left out to the elements to RUST/corrode, or got bent valves/dented or holed pistons in otherwise well running engines with no symptoms of bottomend problems.

And most of us are not as adventurous or comfortable with splitting the cases as you are compared to tearing off the topend. Just trying to provide some rationalizations for the "why" .

T.C.

[IanDMacDonald]

I think I'd rather buy another engine before I ever had to put money into rebuilding the bottom end of my bike.

[duc]

So the summary of original post is that this cheap eBay kit does the job?

[ViperRon]

TC pretty much summed up my thoughts as to why I did not replace the lower end and as far as the clearances I was told by the guy that sold the kit to use the original clearances for piston. Weisco makes a different piston and tends to swell more when heated requiring more space.

TC was also correct about $50.00 a hole to bore but I am sure I could have found a cheaper shop to do it but not sure of what I'd have gotten.


One more suggestion I have for people doing this is make sure the wrist pin fits the rod nice and smooth with no slack. Mine pushed in with just a little force. If yours are like this then you can use a different method to install pistons and cylinders.

I take the cylinder to a bench line all wrings up direction of piston etc oil the cylinders and use a ring compressor to put pistons into cylinders. I put the C clip stop for just the inside of the wrist pin in the piston. I put the cylinder and piston assembly on and rotate till the center 2 and 3 rods are up and slide pistons down till the wrist pin can be inserted too far and rings come out. Center the rod in piston and slide in wrist pin. Put shop towels covering open engine area below piston for safety and put in c clip retainer for both 2 and 3 pistons. Slowly rotate engine supporting cylinder till 1 and 4 rods are about even with 2 and 3 and install wrist pins and retainer clips. You have to use shims to support the cylinder at times but its easier than breaking a ring.

[trbig]

Hey Ron,

Thanks for the update on the "cheap" 1196 bore kit! Remember folks, it's still ~$50.00 a hole for boring!

Tod....I, too, did the smaller (1179) wiseco bore kit on mine with an estimated 50K miles on the lower end....and did NOT split the cases or replace rod/crank bearings! In my thoughts, these engines were overbuilt to last 100K+ miles.
I had had my bike since new, 17 miles, but odometer broke at ~900 miles, never fixed it the 9 years I rode it before it died, that's why the estimated mileage. And as we thought, they(overbore kits) do not necessarily provide much of an increase in power, hence, not much more "STRESS" on the bearings vs. OEM, and with the rarity and $$ of the crank bearings, it was working great before the teardown, didn't expect it to behave any different afterwards.

Perhaps this was Ron's thinking also, not sure, but since "we" are a frugal bunch, if it's not broken, we don't necessarily fix it. Lots of folks acquire these bikes with much less mileage on them, but may have been left out to the elements to RUST/corrode, or got bent valves/dented or holed pistons in otherwise well running engines with no symptoms of bottomend problems.

And most of us are not as adventurous or comfortable with splitting the cases as you are compared to tearing off the topend. Just trying to provide some rationalizations for the "why" .

T.C.

Got it! At least there's a method to your madness! lol.