Hi All fellow petrol heads. I am an experienced rider from NZ. An ex racer 10 years ago, I finally decided to get back into riding and bought myself a tidy little '97 KLX 300 for $1850 NZD, only for use on Trail Rides once a month or so.

SHORT VERSION

turns out my KLX's top end is stuffed. it needs a replacement cylinder, piston & rings, cylinder head and exhaust cam. the cam has damaged the head, and the cylinder is scored.

question: is it possible/ok to rebore a KLX 300 ? if so, how (hone and re coat, or hone and re sleeve ?)

the way I see it, Ive got 3 options.

1) rebore the cylinder ( if its a done thing ) get a second hand head and exhaust cam, and fit new piston etc. this option will cost me around $2500 NZD incl labour

2) go all new parts - new head, cylinder and cam is about $2200 NZD just in parts. with this option the whole job would cost around $4000 NZD incl labour

3) sell the bike for whatever I can get for it to a wrecker, and start again with another bike.


My instincts are to go with option 1, as its the cheaper option, but also because I quite like my KLX for a number of reasons and I want to exhaust all options of getting her going again before I head for option 3... but I have a few concerns:

- will I run into problem with reliability if I rebore the cylinder ? overheating etc ?

- will the bottom end go "pop" once shes up and running to full compression again - the crank feels solid and good, the mechanic agrees that he cant feel anything wrong with the bottom end, but he keeps saying "you just never know"...its another $1000 to get the bottom end replaced while they're in there.

- am I flogging a dead horse ? the bikes only worth $2K, to spend that amount again seems a bit mad, but I will do it if its a viable way to get her going and reliable again, but the $4500 option seems insane, if I'm spending that much, it would be better to put that kind of money towards a newer bike perhaps ?


LONG VERSION

Ive owned the bike for 2 months. Ive done 2 rides on it, totaling about 6 hours riding, fairly hard paced riding but not thrashing it. So, this bike I bought from a guy who claimed he'd owned it for 5 years, done about 30 rides, all with his kids following him around on XR100's, so he said he'd never ridden it hard. The bike was immaculate, the frame has been powder coated, the speedo and rev counter worked, she started first time, no smoke, plenty of grunt etc, even the plastics were perfect - it seemed like an honest bike, I did all the checks - I know my bikes - I even had a check list a page long, I was very thorough when choosing my bike. So imagine my surprise when I park her up as a running bike after my 2nd ride on it, and go to start her 2 weeks later to find shes lost her lunch completely !

the thick of the story is this : someone before me, has had non standard sized shims fitted (i.e. smaller than is ever supposed to go into that engine) to get the last little bit of life out of the engine, or to sell it, knowing it was on its last legs. Its pointless pointing fingers, but its worth noting that the engine has been running like that for at least the 6 hours I've ridden it on, incase that affects things even further.

The only other thing worth noting, is that the swing arm linkage is stuffed, and Ill be looking at getting that fixed at the same time if I persevere with this bike, thats the only other significant thing wrong with my KLX, everything else is perfect....well, you know what I mean.

Basically, my aim is to have a solid reliable bike to last me the next 3-4 years - Trail riding only - no racing. Im not power hungry, I like the 300 as it doesnt rip my arms off but you can make her honk if you ride them properly. I didnt want to sink too much into this venture from the start, as I only get the chance to ride once a month or so and didnt want $10,000 worth of new bike sitting in the shed not getting used. I chose the KLX as they're known for being reliable bullet proof bikes (arent they?). Sure, she is 14 years old, and I knew the risks, Im surprised that its come to this so soon, and thats its such an expensive fix either way.

I really just need some advice, from anyone who has done this particular rebuild before, or been in a similar situation with an older bike, or just someone who cares, all advice is greatly appreciated, even if its not what I want to hear, please, I'm really not sure what to do. Ill spend the money if I have to, but not if its going to be pointless down the track.

thanks in advance, from NZ.

I had the same problem with my 01 klx. Except my intake and exhaust cam were both shredded. I bought a head with both cams off ebay for 225. Depending on your experience level you shouldn't need a mechanic to do the work. I'm 17 and swapped my head. As long as your patient and follow the excellent write-ups on "planetklx.org" its really pretty simple. You can send your cylinder off to a place called "kustom-kraft.com" and they will bore it to a 330cc and also provide all the parts needed. I know shipping might be high to NZ, but if you look at the big picture, with you doing the work your looking at around $900-$1000 USD'S.

It's all doable by anyone that can follow directions, knows how to properly use a torque wrench, and can "buy it now" on ebay. I'd do it all myself and save about 50% of the total cost, as well as know it was done correctly the first time.

I ve got a parts bike . let me know exactly what you need . I do have a good cylinder and head . i ll make you a deal on some parts.

If you are handy with a wrench and all the rest of your bike is good I would definitely bore it. Kustom Craft is an option as they will plate the cylinder. I went with the Bill Blue 331 kit although he sells 340 and 351 kits. With my kind of riding I was concerned with heat buildup so I wanted to stay with a dry sleeve. The additional power is great and it will be about the same price to do what you have to do in rebuilding to stock specs.

I'm pretty handy with a wrench, I used to rebuild my 2 stroke engines with no problem, 4 strokes scare me a bit more, with timing chains etc.

yes - the rest of the bike is good, seems a shame to just throw it away.

So KAWBOYBILL - have you had any reliability issues since doing the rebore ? did you leave the bottom end as it was, or do that at the same time - was the bottom end a concern for you at all - with all that extra compression , or am I just being paranoid ?

bikerman32158 - I need a replacement head, and a replacement exhaust cam - looks like its better to stick with the cylinder and get the rebore option done, so just the head and cam for now. could you email me on morgansamuel at paradise dot net dot nz ?

thanks again guys...

I've found these on eBay....what are these like in terms of pricing - is that about right ?

http://www.ebay.com/...9#ht_500wt_1180

http://www.ebay.com/...#ht_4655wt_1165

also a set of cams....

http://www.ebay.com/...#ht_1823wt_1165

a bit nervous about purchasing 2nd hand parts internationally, postage is not the worry, its the fact that I can't check it out myself. anyone in the states close to where these are want to make some money checking them out for me ? i would happily pay for ur time. NZ is a great country, but we really are in the middle of nowhere...and we have no airforce
any thoughts appreciated.

If at all possible, it would be the best to buy a head with the cams from that head. Simply because the cam journals wear with the cam.

silver98mustang said:

thanks mate, how did you find your KLX ran after the 330 upgrade - reliability wise ?

Pass on the cams. There's no ACR unit on the exhaust cam.

On the head assemblies, as long as they aren't been damaged, the only thing you may have to change is the intake valves as they have a tendency to cup with use, closing up the clearance to the lifter.

Do look for cams from a 2003 or newer engine so that the ACR timing will be in the factory "easy kick" position.

The crank and rod are strong.

Good luck

Ride on
Brewster

morgansamuelnz said:

Was that question to me, if so, I'm at stock bore.

I revived a distressed blown big bore KLX with ebay parts and it is doing just fine. Be careful and inspect things well and all should be good. I ever reused the rings since end gap was still within specs.

Did not have any bottom end concerns with adding the bore kit nor have I had any problems with the Bill Blue parts and work. He makes a 351 kit but it is a wet sleeve and I was concerned about overheating due to the type of riding I do so I went with the 331. I have about 600 miles on it now and 400 are tougher trail type miles and as of yet do not have any issues. He might have some insight on a built up head laying around that might be for sale also. Good luck on your project.

It tells me your email is invalid.....

thanks KAWBOYBILL, thats the final push I needed. cheers.

brewster - Im highly embarrassed to admit this - but I dont know what an ACR unit is. can you enlighten me ?

The ACR is an Automatic Compression Release. It attaches to the end of the exhaust cam, and is supposed to make starting the bike easier. The ACR was mistimed by Kawasaki until mid 2002. The mistiming made the bike harder to start, and put more pressure on the already weak idler gear. I believe all that is correct, if not, Brewster will correct.

silver98mustang said:

Having the ACR timed properly is like reducing the compression ratio when kicking the engine over. It automatically goes the full compression when the engine rotates faster by way of centrifugal force. It will not compensate for zero intake valve clearance or carb problems, both of which can make the bike harder to start.

Ride on
Brewster

just thought id give an update for those who are interested, the rebuild is thoroughly underway.

Moral of the story = never believe a mechanic working for a dealership.

The mechanic who took my engine apart (the engine failed while I was away travelling with the bike) said these words in our first phone conversation " your head is completely wrecked, theres bad damage to the cam journals, you need a new exhaust cam and you definately need a new barrel & pistons. Its going to be about $3500 just for the parts". Enter the phone call 5 mins later from the Salesman in the bike showroom, offering me 3 or 4 very well priced new/near new options - using the "your going to sink so much into this old bike, you'd be better to put that money into a new bike" type sales pitch. I considered it seriously, and whilst he had a point, I just plain didnt have $9000 to spend, not now anyway - i need to buy a house for my family first - then Ill get a new bike...It just didnt sit right with me, I'm not the kind of person to throw things away, I like to persevere and fix things, provided it doesn't financially ruin me...

so heres me searching NZ & Australia for second hand parts to NO avail thinking "ok, my bike is dead and im not spending that much on new parts. maybe i should give up..."- I'd returned home without the bike (couldn't take it on the plane - so planned to retrieve her in a few weeks) and I hadnt seen any of the parts - even if i had - I still wouldnt have know what i was looking for. BUT, enter bikerman32158 & brewster - you guys are angels of the motorbike world. Through guidance from both of them - bikerman even taking his parts KLX apart for me and offering to sell me his head for next to nothing... I got my top end parts sent down to me from the bike shop, took some quick pictures of the damaged areas and sent them off to a cylinder/engine recon shop (who I'd been waiting 2 weeks to open after xmas - long 2 weeks i tell you) who replied straight away saying " this is no where near as bad as we were expecting, we can replace all parts need and repair the small damage & set up your head for around $1700 NZD - we have a re-bored 308cc barrel here ready to go on an exchange basis which would be included in that price"

when I read this, I literally jumped up and down and howled with delight - it seemed all was not lost with my beloved old Bethany (yes, i name my bikes, i name all my cars too

so....I wanted to attach some pics of the head etc pre-recon, but it seems I cant do that unless im a special type of member or I have somewhere to host them, might get onto that now - I'm going to blog the whole rebuild with pics once I get the head back next week, Its up to me to get it back together and going again. I'm both nervous/worried I'll muck it up, but also confident I'll be able to figuire it out, i used to rebuild my 2 strokes almost blindfolded, surely timing marks and cam chains cant be that hard !! so watch this space, it could get entertaining


also - anyone alse find this site slower with the new format ?