Big bore reliability and mpg

[SurreyHills]

Been hunting for a drz to commute on, seen a local one for sale, specced to the max including a bore upgrade to 430. One of the things I like about the drz is its reliability, with a bore upgrade how does this effect reliability , servicing etc and what about mpg. Mind I exect a bore upgrade makes the bike a blast, how much better?

 

And from a UK perspective does a bore increase hike insurance up.

[Signman606]

Been hunting for a drz to commute on, seen a local one for sale, specced to the max including a bore upgrade to 430. One of the things I like about the drz is its reliability, with a bore upgrade how does this effect reliability , servicing etc and what about mpg. Mind I exect a bore upgrade makes the bike a blast, how much better?

 

And from a UK perspective does a bore increase hike insurance up.

 

If it's the right BB kit, it shouldn't affect reliability in any way. The Cylinder Works kit is well made, and the piston provided is excellent (Vertex). Servicing would be the same, but your MPG will go down slightly, mostly because of the "wow' factor......it's noticeable over stock, and if you're like most of us, your right hand will be more cranked to the WOT position. This is one of the better mods imho, better than a carb.......with the stock carb and jetted properly, this will make a huge difference in performance. It would be nice to have a good aftermarket header and muffler to go with for breathing........doesn't have to be the MRD, there are other choices that will work well too. You mentioned spec'd to the max, so maybe that's already part of the package.............if you get it, post up some pics, we all like seeing new blood.  ?

[SurreyHills]

Thanks, good to know, all new to me, it looks, feels right, so fingers crossed, as a newb I dont expect to be killing the thing, but nice to have a little extra in reserve, checking it out later.

[38super]

Did they specifically ask to list the modifications?

 

edit, if Namura BB, look else where.

Edited May 4, 2015 by 38super

[yzf128r]

As posted above, a big bore (done properly) will not have any negative effects on reliability. I've had mine bored since 07 and have not had a single problem. As far as fuel mileage, it is down a bit, but not much. Commuting back and fourth to work I get about 95 miles before hitting reserve. If I remember correctly, when it was stock I would switch to reserve right around 100-105 miles. If I'm out playing, I usually hit reserve somewhere around 60 miles.

[Stuwy123]

Stock gearing, FCR, Yoshi RS-2 (corked), KN air Filter (not that it does much for power), 240lbs geared up, I get 36mpg (lots of WOT highway).

If I'm nice to the throttle (making sure I don't lose the GF),it'll do 59MPG without much effort.

 

So at WOT, you get a 2MPG drop, and cruising speeds (varies much more) gets you a 4MPG drop.

Not too terribly bad.

[Mr-Adventure]

And from a UK perspective does a bore increase hike insurance up.

If you don't tell them, they won't know.

There is no visual indicator of a larger bore, for all intents it looks bone stock.

[hinksy]

If you don't tell them, they won't know.

There is no visual indicator of a larger bore, for all intents it looks bone stock.

 

Unless it is an athena or ice cube , So if there are no outward signs , dont say anything . The one thing that will count on the reliability will be who installed it , so if it was a poor quality bigbore ( namura ) and it was just slapped together in his backyard , then who knows . Ask some questions like , what type of bigbore is it ? Who installed it ? How long has it had the bigbore ? and so forth . If done properly it will last as long as a standard motor , but can have up to 15 more horsepower when you add carb , cams and pipe . I have had mine for 5 years without a problem , greg