Just got done tearing the motor out of my brothers sled. He has a Indy Triumph. We went up to the UP last weekend and it started to idle REALLY high. Popped the hood, because it didn't sound right to me. Saw that one of the nuts had backed off the stud holding the cylinder to the base. After looking closer, we noticed that three of the studs were completely snapped off and three with the nuts backed off, leaving only the two nuts on the PTO side left holding the cylinder on. Anyone ever see this before, or have any idea what might have caused this. Thanks, Butch.

I've never seen it to that extent, but I have seen the nuts loosen off, and I expect that's what happened. The nuts looses off, the resulting vibration spanned the studs and the air leak caused the high idle.

Lucky you guys caught that

the older polaris triples 600-650's with pipes use to do this all the time. are you turning it at higher revs?

Thanks guys. No, not turning higher rev's now, but when it was new it would idle at about 3,500-4,000. It also sucked some major fuel. I rejetted and turned the idle down for him. Dealer/mech. said he's seen it before and shouldn't have caused any damage to the lower half (that's what I was concerned about). So I guess I will put it back together. would it be alright to put some blue loc-tite on those nuts to keep them from backing off? Or is that a no-no?

Blue lock tight should be fine.

Hey Butch,
Further to what H20XER said, this problem was fairly common, even for non piped Polari triples. I owned both a 91 and 92 Indy 650 (loved them!) which were stock other than a wee bit of clutching (springs). Both of them snapped cylinder studs just as you described under fairly normal conditions.
Come to think of it, my buds 92 RXL (early efi version of the above) also did the same thing.
Must have been a casting issue with early fuji triples?

Have a friend with one of these sleds I'm about to go through for him. He bought it new and has about 1200-2000 field bombing in SE MI miles so I wonder if it's shaken anything loose. Definetly something to look at.

Anyone think or know if this will be a re-occuring problem, or is it a factory flaw and everything will be O.K. after I fix it? Thanks again, Butch.

Seems strange to me as I've owned a '94 and '99 XLT both of which had fairly high miles on them with zero bolt issues. Maybe its a fluke or perhaps one came loose which is what caused the others to either loosen off or break.

Rick.

Seen it before.

And I contest - It is NOT a factory design flaw.

This problem developed from assembly- Not from design.

Uneven torquing of the stud or poor surface prep.

Double check the mono block - Place it on a large miror and look to see if the mating surface is completely flat.

At assembly, make sure you evenly torque the bolts and use locktite 242.

base prep is as improtant as monoblock flatness.

To make sure it never happens again, do the following:

1. Split the case and inspect the upper case for flat surface on mirror
2. Inspect the upper block for flatness on mirror
Before doing these two things - make sure all old gasket material is removed
3. slightly "rough up" the new surfaces with a 200 grit emery cloth.
4. change out any questionable studs
5. Tighten up stud bolts at assembly with common pattern assembly - working your way away from the center.
6. Don't forget - use a very liberal amount of LocktiteŽ 242 at assembly.


The main problem here is that the block is somehow failing because of a cyclic torsional load - even matched mating surfaces removes the load completely.

Email me for specifics on assembly.

Just my 2 cents

Normal cause of this failure is excess torque on base nuts. Always use new nuts, torque to spec.


RIDE SAFE
P.S. you lucky it didn't crack cylinder.

Thanks everyone for your help. I got the studs out (finally), now I just need to wait for him to get me the parts. Thanks again, Butch. :)