KLX300R with suspension upgrades and questions

[sidewndr46]

I bought a KLX300R that has a bunch of modifications at a decent price. I've ridden it once so far. The previous owner gave me a sheet from "Moto Pro" that said it has been revalved and resprung both front and rear. The springs listed for the front is a 0.44 kg/mm spring from Racetech. The rear spring is listed at 5.8 kg/mm, which is the stock rate anyways. So I have no idea why they resprung the rear.

 

The issue is the bike is basically unridable. The motor is really difficult to start when hot. It has a Keihin flat slide carb, but no choke. Also stroker exhaust and hot start kit. It is extremely difficult to kick over when the motor is hot, even 200+ lbs guys struggled getting it started.

 

The rear end is bouncy as crap and seems to lack any real rebound damping.

 

Even if I get up to fourth gear and brake as hard as possible on the front, there is zero front end compression. Going over rocks and small obstacles the front doesn't move at all. However, if you find a huge single jump and hit it full throttle, the bike basically completely adsorbs the jump and the landing. Almost like it wasn't there. When you do that the suspension will go through most of its travel.

 

The brakes are incredibly stiff. I flushed the front brake, but it has basically no feel. You can't feather them at all.

 

Does anyone know what moto pro could have done to the suspension? The 0.44 kg/mm spring is the lowest rate aftermarket spring I could find, but is still much higher than the stock 0.37 kg/mm springs. It almost seems like this bike was set up for motocross type riding or something.

 

At this point I am considering just giving up on this bike and cutting my losses.

[hadfield4wd]

Sounds like the bike needs finished. I have several klx's one stock and the other completely modded. They are a joy to ride.

What was done as far as valving? When was the shock done? I do mine yearly.

Edited October 12, 2016 by hadfield4wd

[brewster]

Is the carb a "pumper" carb? It should be. Hard starting when hot is one indication that the intake valves have no clearance.......a common problem with the KLX300.

As to the suspension, what is your riding weight? Sounds like the springs in the suspension are set up for someone around 180 lbs. Check "race sag" at both ends. Measure the difference in suspension travel from the forks and then the shock at full extension and then with you on the bike. A guideline is that the forks should compress 1/4 of their travel and the shock 1/3 of its travel. That will let you know if the spring rates are close for your weight.

Ride on

Brewster

[sidewndr46]

The intake valve clearance is fine, I checked it myself.

 

There is no explanation as to what was done on the valving other than "revalved". For all I know they replaced the valve stacks with washers from home depot.

 

With gear I'm about 160 lbs.

[hadfield4wd]

Also no choke. What does that mean? Is something plugging the hole where the choke is? Is something plugging the hole for the hot start? I will say if you're patient we can help. These bikes will run fine.

And I agree with brewster 100%. Set up sag. You may just need new springs. I may have a set of stock front springs laying around. I'm not sure I just moved and I purged a lot of stuff.

[jalopyguy]

"It is extremely difficult to kick over when the motor is hot, even 200+ lbs guys struggled getting it started."  Was the kickstarter really stiff or the kicking it over was normal and it just wouldn't start?  If the kick starter was stiff or really hard it sounds like the compression release mechanism isn't working.

[sidewndr46]

"It is extremely difficult to kick over when the motor is hot, even 200+ lbs guys struggled getting it started."  Was the kickstarter really stiff or the kicking it over was normal and it just wouldn't start?  If the kick starter was stiff or really hard it sounds like the compression release mechanism isn't working.

 

Thank you jalopyguy for pointing this out. I looked through my photos I took of the valve train while doing the clearance inspection. I compared them with the parts fiche and some others online. The ACR that should be on the exhaust cam is missing completely. I think that explains why starting this thing is so difficult.

[hadfield4wd]

You'll want to replace the idler gear as well when you put the kacr on.

[DirtRockr]

I have stock fork springs available, if Hadfield4wd can't find his. I'm about same size as OP and run 0.46 race tech springs/gold valves.

[sidewndr46]

So you can't reinstall the stock decompression mechanism once the Stroker decomp lever is installed into the head. The decomp lever had never done anything since it was originally installed. To get it useful, I cut the little spring in half. Then I put the cable and lever back on, and with the lever fully pulled you can get just a little bit of decomp. This is really all that is needed, so it is easy to kick over and clear after dropping the bike.

 

I got some stock springs off eBay. I put them in with Bel Ray 7 weight oil. I think the 5 weight oil would be a better choice. The 7 weight is pretty high viscosity. So far messing with the compression clickers on the bottom of the fork does nothing. I am probably not riding aggressive enough to matter yet. But at least with the softer front end, the front and rear can work together when riding the trails. It still can handle smaller jumps if you're careful, but I mainly do woods riding anyways.

 

In the process of working on the front end, I discovered the front brake rotor is bent. I ordered a replacement used rotor along with rebuild kits for the master cylinder and front caliper. The upside to this bike is while the forks are not identical, the rest of the parts on the front end can be exchanged with the kdx200 front end I am using on another bike of mine.

[chaley]

I would recommend sending the rear shock and have it "rebuilt" and set up for you and your weight. It sounds like someone forgot to put the oil in the shock or completely had no clue as to what they were doing with the shock and valving . I have 2 KLX 300R's I run the snot out of one of them. I have never been completely stranded ever. The worst thing that happened was we were miles deep in the woods and I could not shift out of first gear. A spring fell off the shifter "drum?" I laid the bike on its side and pulled the side cover off and replaced the spring which was laying right under the shifter drum where it fell off. This was at night at the lake house using a flashlight. Never had an engine problem since. As for starting with an inoperable ACR takes finesse. You must place the engine in the proper cycle position (right after TDC of the compression stroke) and have the kick starter all the way up full a full kick.  You WILL break teeth off the idler gear if you don't. Hot starting after a layover is a total buzz kill. Hopefully you're near a hill and can roll start it in 3rd or 4th gear. It is time for a complete top end rebuild, possibly a big bore kit, carb/exhaust and suspension complete rework. (always replace the idler gear for the kick starter) The main bike I ride has all the free mods done. I have always wanted a newer bike in the 450 range. I lost my riding buddy so I don't ride nearly as much right now. I live in a state that has some of the best riding areas in the country. Would love to find someone who rides at the same level and pace I do as my last friend did.  In stock trim the 300R is a tractor that will drag you up a rocky hill without clutching it. The sacrifice is throttle response.

Edited December 12, 2020 by chaley
misspelling

[Piney Woods]

Four years ago, he probably has moved on.