I added a kicker to my 300EX

[RichM1983]

Ok guys I have a problem with my 300ex. I built it a while ago and it never would run right. It would always drain my battery and I couldnt continue working on it because I had to wait for it to charge. Finally I guess the starter took a dump on me. So I added the kick starter and all the internals as well as the side cover from an old 250x bottom end I had.

I need to get the wiring right. So heres the questions:

Will a 300ex start if its in reverse?
Do I need to ground the wires that plug into the wires that come from the 300ex cover behind the brake leaver so It will start? I think they are grey and green. If Im using my 250x cover won't I just have to ground the wires that would normally plug into the wires from the clutch cover to get spark?

I currently have spark but it seems week to me. Its not blue its orange and doesnt seem strong.

Thanks for the help.

[honda300EXtreme]

yes i do believe those wires will need to be grounded, and no the 300ex will not start in reverse

[RichM1983]

Thanks a ton for the help. That must be why it won't start. Since I Haven't got those wires grounded it thinks its in reverse and wont spark well enough. Thanks again.

[ZSNOW]

i wanted to do this to mine too. any pics?


but im sure i don't want to kick over 14:1 compression:devil:

[RichM1983]

Well mine is a high compression piston for a 250x but its in a 300ex which means the compression is even higher. I'll try to get pics up.

Anyways. I got it started. I ground out the reverse and the neutral wires and it started up.

********PLEASE READ ONE I NEED MORE HELP**********

Now I have a new problem.

The bike starts fairly easily now and runs and idles good.

The problem is that when I give it gas while its sitting in neutral it wont rev all the way. Its almost like when you rev it up in reverse and it is limited. When I ride it it won't run right at all past 1/4-1/2 throttle. Its all jumpy and breaks up badly. I know the slide in the carb is opening because I had trouble with that and its fixed.

Does anyone know what to try to fix it? I'm lost. Thanks for the help.

[honda300EXtreme]

hmmm..

either the carb needs cleaned out good.
or it still sounds like the reverse inhibitor is kicking in because it still thinks its in reverse

did you ground the wires seperatly?

[RichM1983]

I know its not the carb. It has been cleaned so many times that the metal is starting to wear. lol j/k but seriously though its been cleaned severeal times.

I re-jetted the carb with a main that is like a 134 or something. The mods include a full E-series exhaust and a header, new airfilter, lid removed from the air box, high comp 250x piston, and a 250x carb.

I wired the reverse and neutral wires together and then ground them with one wire to the frame. Is that incorrect?

[honda300EXtreme]

that should be your problem, try grounding both wires seperatly so there not touching, im 99% sure thats your problem

[RichM1983]

Thanks a lot thats great. I hope your right.

[bwamos]

Shouldn't be a problem combining and grounding, works fine on mine.

I'm guessing youve simply getting a poor ground. Probably got paint or oxidation on the spot you're frame grounding it too, or even a poor aloyization (is that a word, lol)/bonding at the solder. Any resistance will jack up how it reads.

Get some aligator clips and ground it straight to the battery ground as a test.

Also use a multimeter and make sure there's a direct short between the grounding point and the ground terminal of the battery.

Also as a secondary possibility.. make sure the little switch on your clutch lever is working properly. If it isn't it won't let you start it in gear because it thinks your clutch isn't disengaged. Should let you start in neutral though.

[RichM1983]

Originally posted by bwamos
Shouldn't be a problem combining and grounding.

But, I'm guessing you're getting a poor ground. Probably got paint or oxidation on the spot you're frame grounding it too. Any resistance will jack up how it reads.

Get some aligator clips and ground it straight to the battery ground as a test.

Also as a secondary possibility.. make sure the little switch on your clutch lever is working properly. If it isn't it won't let you start it in gear because it thinks your clutch isn't disengaged. Should let you start in neutral though.

For temporary reasons I have it ground to the magneto cover to see if it would start. Is that a bad idea?

I also dont even have the little switch on the clutch perch. The switch is ther but no wires are connected to it. Could that be a problem with why it won't run right?

It starts pretty easily now it just wont run right past 1/4 throttle.

[bwamos]

Originally posted by RichM1983
For temporary reasons I have it ground to the magneto cover to see if it would start. Is that a bad idea?

I'd say yes.. because of the gaskets etc... you're relying solely on the conductance of the bolts. And, odds are those bolts/threads are probably a bit oxidized.


I also dont even have the little switch on the clutch perch. The switch is ther but no wires are connected to it. Could that be a problem with why it won't run right?

No, but I beleive it needs to be actuated in order to start in gear. Cant remember if it's a normaly open, or normally closed switch. Easy to check though.


It starts pretty easily now it just wont run right past 1/4 throttle.

You're definatly getttinga poor ground on the R indicator wire. Does the old rpm bounce at about 3000-4000 rpms? ;)

[RichM1983]

Yeah its definately around 3000 rpm. Maybe even less.

So I need to move the groun to a proper place and make sure the paint is gone so it gets proper ground and that will probably fix it.

Thats good. I hope so.

Also I have a clymer manual but how would i know if that clutch lever switch is normally open or closed.

Thanks a bunch for all the help everyone!

[honda300EXtreme]

now that i think about it bwamos is right (as usual :p ) combining the grounds shouldnt have any effect,

it has to be a bad ground,you could always ground them to the bolts that hold the rear brake master cylinder in place. temporarily.

[TRX-330]

I would really like pics of the kick on it, and what all had to be done to make it work. Also how much more compression dose it get with the 250x high compression piston?

[RichM1983]

I will try to get a proper ground and see if that works.

As far as the kickstart system goes for the 300ex its fairly simple KINDA.

-All you need is the 250x cover or machine a 300ex cover to accept the seals and things for the kickstarter. I just used a 250x cover.
-The next thing you have to do is put the kickstarter assembly in the cases. Its simple, simply bolts right in.
-Then you have to put the gear that contacts the kickstarter gear in. Thats simple as well the hole is still present in the 300ex cover.
-The next part is the hardest part. You have two options here. First option is that you can split the cases and change the reverse shaft from a 300ex shaft to the 250x shaft. The reason you need to do this is that the shaft on the 300ex doesn't go through the right center case and out into the clutch cover side of the motor like the 250x shaft does. On the 250x there is a gear that rides on this shaft the contacts the clutch basket so when you kick it over it can spin the engine. Second option, which doesn't require splitting the cases. What I did was take a shaft from a 250x and cut it. I cut it at the end that has the dowel pin in it. I then used the dowl pin to hold the end of the shaft in the case so it won't come out and hit the clutch basket. You need to groove the shim that goes behind the gear so the dowel pin will be hid behind that and not bother anything. This option may be more dangerous because of the stress it places on the hole that is in the cases. So far so good for me though. I hope it doesn't bust the case where the shaft is.
- The last thing you have to do is take out the oil pipe that is equipped on the 300ex bottom end. This pipe is not eqipped on the 250x and this should not have any adverse effects on the motor. It may be a nice addition but its not necessary. If it were then the 250x bottom ends would have been junk, which they are not. They are strong bottom ends. The reason you need to do this is because the 250x clutch cover wont work with the oil pipe, they covers are different. If you use the 300ex cover then you will still be able to use the 300ex oil pipe.

As far as pictures go I can't because the clutch cover is on the motor. If you need any clarification just ask.

My compression with the hi comp. 250x piston in the 300ex is over 200 psi. I think its 220. I was told that race gas is not necessary for the motor to run from people who race with this setup and they run pump gas.

[honda300EXtreme]

yea let us know how ya make out.

congrats on sucessfully doing the conversion though, many have tried it and few suceed

[TRX-330]

got any pics yet?

[RichM1983]

No pics yet. I've been working on a banshee lately and don't have time for the 300. I may get to it one day soon. I will probably just end up selling it.

Anyone interested? I have a complete bike plus tons of spare parts including swingers, stems, axles, cases, trannies, a-arms, harnesses, cdis, bumpers, 3 frames, tires, rims, brake parts, chains, grommets, and other parts.

The bike is a 250x frame with a 300ex motor with a 250x kickstart added.

$800 OBO takes it. I live in near Charleston, WV.

[dabomb_350x]

Here are some pics, when I was checking thing out in a buddies bike whe we was installing a timing chain.

[dabomb_350x]

Another

[dabomb_350x]

Last one. Notice how the gear closest to center does not have shaft holding it in place.

[MTDman11]

sounds cool man. i like the electric start tho for the winter. they are a pain to start sometimes. my winter experiencses are it sleeting and then everything litterally freezes on my quad. like the igniton and switches shifter leveers tires everything!

[SET THE STAGE]

is that where the reverse shaft would be like the guy mentioned above?

[dabomb_350x]

Yes that is where the reverse shaft would be seen.

[atvnut22]

can you just switch the 300 bottom end with the 250 bottom end

[SET THE STAGE]

Originally posted by atvnut22
can you just switch the 300 bottom end with the 250 bottom end

you could, but you'd have a shorter stroke (which would equal it out to the 250x's CC amount since they have the same bore) and you wouldn't have the option of electric start

[atvnut22]

it just sounded easier cause i want o get rid of my e-start, cause puttin in the kicker sounds like a butt. but if its gonna make me loose power then im not doin it

[ZSNOW]

you may lose .5 of a horse from the shorter stroke, but you will make up for it with the faster reving of the shorter stroke 250x motor, on a moto x track the 250x motors are faster than a 300ex with the right rider..

[TRX-330]

Did anyone ever get pics with the crank case cove off and all the stuff assembled? Id really like to see how it works, and where can i get the stuff cheap?

[thyman17]

I did the same thing. I put all the internalls from a 250x into my 300ex bottom end. I kept the 300 crank and everything. So i can still have e start if i want even tho my battery is dead. It wasnt hard at all it took me about an hour to do and it starts usually one or two kicks in the winter. Its great to have for racing if you want to get rid of the weight of the battery and still want the power of the 300ex. Im thinking about doing a how-to if i rebuild my entire motor again..

[TRX-330]

Please do, with pics cause with the combination of both information i think i can do this also.