My 85 R's cylinder is out of bores and was wondering if I should stick with it and have it re-sleeved, or if it is worth buying the newer 88/89 cylinder? Are there any advantages to the newer cylinder? Do they run any different? How will my '85 head work with the newer cylinder? Thanks for any info.

Keenan

 

well 85 cylenders are soposed to have the best stock porting(thats what i got)
and the other years arnt as great
you probably already know but you cant put a 87-89 cylender on a 85-86 bottom end

 

If an 86 cylinder will fit a bottom-end, so will all other years!
What year cylinder used is no big deal, it when you change pistons/cranks that you got to pay attention.
Shop around for the best price on a cylinder. If you can get a used one that has some bores in it still for less money than a resleeve, go that way.

 

IMO the 88 cylinders are the best. The bridged intake offers better piston reliability and the port timing is slightly better as well.

They will also work with you head and crank. If your using an 85 or 86 crank you must use an 85 or 86 piston.

 

you can put any year jug on any year bottom end. to put an 88-89 jug on an 85-87 bottom end, you need to use a spacer plate and a longer rod because the 88 and 89's used a 5mm longer rod than the 85-87's. this is why they get a little more top end revving, and why the 85-87 have more low end grunt. you start to make the real power when you stroke things. 86-87 have different pistons than 88-89, doesn't matter which combo, just personal preference and what your intended use is.

88's did have the bridged intakes, which i personally feel helps with reliability, and will produce a shade more power...but nothing noticable.

 

From a longevity standpoint, the '86 cylinder would be the best due to being able to punch it out to .140" as compared to .080" for the '87 - '89 cylinders. Again, just based on the number of bores the cylinder will take.

 

You can bore an 88 cylinder to .140 over as well. Just use an 87-89 crank and cylinder with an 86 piston and a spacer plate.

Or use an 86 crank and piston with an 88 cylinder.

 

Wait a sec!! Some misinformation here!!
The 86 piston is different from the 87-89. 86 is the only Fourtrax that is different!Same goes for the rod length, the 86 has a shorter rod.
Many people say the 86 will rev faster and higher due to the rod length.

You can run any year jug on any year bottom-end. You don't necessarily need a spacer plate.

The only time you need a spacer plate, this is for any year jug, is if you are running an 87-89 bottom-end crank/rod with an 86 piston. Why? Because the 87-89 have 5mm longer rod and the 86 piston has the wrist pin located 5mm lower in the piston. This will make you 5mm longer.
This does not increase your stroke! All Fourtrax Rs have the same bore/stroke.
You can't bore an 87-89 cylinder past .080 unless you resleeve it. Bore past an .080 and the sleeve is too thin and not usable. You can bore an 86 to .140.

 

Thanks Trapperb1, I thought I was correct on the '86 cylinder versus '87 - '89 as far as bore sizes!

 

I prefer the 88 cylinders over the others any day. I currently have two of them (one .100 over and one .110 over) and love to use the larger 86 pistons.

My .100 over 88 cylinder has been running strong for over two years now with 60 HP at the crank!