I really hate to read this. I've ordered a 351 kit, and now I'm a bit nervous. I'm a woman who will be traveling alone once in a while, and I defiitely need my bike to be reliable, as I'm not a mechanic. It seems like this is probably an isolated incident, but what do you guys think?

 

There's ALWAYS the chance that a mechanical thing like a motor is a lemon.
I'd say the changes are about the same with a stock bike than with a properly installed 351 kit.

--
Mikko

 

No, I don't think this is a pattern or inherent problem with the 351 in general. I only posted the original post and this one as a point of interest for what is apparently a hard to diagnose issue with merickk's bike specifically. I wouldn't worry about this for considering a 351. For the really paranoid, however, one could stay with one of the big bore kits that keeps the water jacket intact. I think this is what Blackheart58 went with. Still, this thing with merickk's just seems to be a weird anomaly.

 

Well that's what I was thinking, since it's the first time I've ever heard of a failure. I thought that the 351 was the largest bore they could make while keeping the water jacket intact. Could provide more detail on this? How is the 331 or 340 kit different than the 351 in regards to the water jacket? I understand some of the technical stuff, but I'm no mechanic.

 

I've been following the posts on the 351 kit since my bike was new. I read nothing but great things, and I was only waiting for my bike to get out of warranty to get one. My warranty was up in August, so I ordered the 351 kit this week, plus a bunch of other upgrades. Now I read this. I don't know, but I'm really thinking this guy just had bad luck. But then it's put that thought in the back of my mind, so that's not so good. I ride really easy (slow), I'm really light weight, and will never cruise over 65, so I figure I'd be less likely to have an issue than most, but then you never know. I will probably proceed with the kit, although I have contacted Bill to see if he recommends this kit based on my riding style, or if the 331 or 340 would be more suitable. I do have a good mechanic that will be doing the work.

 

Seems like the "stuck in Ouray" guy had a problem withhis coolant system that was a major contributing factor.

Bear in mind that these little thumpers have very small oil reservoirs. If you are ringing them out you need to keep an eye on the oil level. If you do that, and keep up with any losses you'll be fine.

I'd be interested in a deal on a 351 if any of you folks who have one change your mind!

Kevin

 

You gotta look at the big picture. How many people have perfectly running 351 kits? I don't know for sure, but it's probably a lot.. How many people have had failures? Again - I don't know for sure, I can only name two.. This guy, and jhoffy who's was installation error..

I wouldn't let a couple bad experiences put the axe on the 351 kit when there's XXX amount of positive experiences.

My 351 kit is #9. I had a head gasket prob in the beginning, but that was due to the solid copper head gaskets they used to come with. Now they come with steel braided. Since I switched (Bill sent to me for free), I haven't had any probs. That was about 3k miles ago. I'm on about 6k with the 351 kit.

If the bike was stuck on 250cc's I'd have sold it a long time ago!

 

LOL!...I was wondering if you'd chime in. You're as hard as anyone on your KLX, and I haven't seen or heard of any catastrophies related to the 351 kit. I don't think the kit is the issue. Something unusual is going on with merickk's, and hopefully the real culprit will be found out. It makes you wonder if the sleeve was even the real issue the first time around. Merickk is a decent mechanic who's been around on ADV for awhile, so I don't think we're looking at a jhoff situation.

 

I had the 351 in for 5,000 miles plus. Zero problems. Bike had 9,000.

Bill changed to a head gasket with a fire ring a long time ago. This is a sealing ring that only presses on the sleeve and head which is what is used on most diesels with compression ratios in the stratosphere. So much for head gasket problems.

I never had an over heat problem or any other problems. I just rode the crap out of it. I traded the bike in a couple of weeks ago for a Versys. Some one is going to get a sweet KLX351SF!

david

 

The 331 is the largest kit Mr. Blue offers that doesn't cut into the stock water jacket openings. I ride in temps over 110 degrees, and in very tight, steep, long uphills (did I mention hot?), and I just wanted to be ultra-sure. However, just because the 340 and 351 kits cut into the water jacket openings a tiny bit, it doesn't mean it decreases flow through the water jackets. It may not even increase the pressure required to be generated from the water pump to maintain normal flow. I know it's "common sense" to think cutting into the jacket will affect the flow in some way...well...that's not how fluid dynamics work. Unless the current stock system water jacket design is the bottle-neck which limits flow of this system, you may be able to decrease the water jacket openings by 100 times more than the tiny amount present in Mr. Blue's 351 design, and see no difference at all in coolant system performance.

I wouldn't hesitate to run a 351 in my bike, if I were to buy another bike some day. ESPECIALLY if you are someone that doesn't abuse the engine, I'd say don't hestitate to get the 351 Mr. Blue makes. It's not going to have a greater tendency break than any other machine, assuming it's assembled correctly...and that should be evident early on when first riding it after it's done. Even if you DO tend to abuse the engine, a 351 isn't going to be more likely to break than any other well made kit.

YMMV.