Official 300ex Engine Build up Thread

[Cody_300ex]

I keep seeing posts in here of people asking what they should do to there 300ex engine, so I figured with my decent knowledge of the 300ex engine I would make an official thread of suggestions. I suggest using a Sparks, or HMF/WB combo exhaust, and a stock 400ex Carb with all these set-ups. I recommend buying these parts from www.magicracing.com

If you’re on a limited budget and looking for some serious power with out going to deep in the motor I would suggest this: Web cam Stage 3, Kibblewhite H/D Valve Springs, Web hardened rockers, and deck/shave the cylinder head .020. This way you don’t have to tear down into the jug and piston. If the parts are bought new it will run you around 370 dollars give or take, & if you do all the labor. This set-up will work well for an rec rider, or a part-time racer.

Now this one is if you’re willing to tear into the jug/ piston, but still on a limited budget. If this is going to be a strict race machine with only race gas ran threw it, I recommend a 12:5:1 or 13:1 compression piston, but it may require a Heavy duty Battery and Starter. If it going to be some-what of a daily/trail rider I would just go with a 11:1 and the shaved head to keep most of the reliability of the motor. I would put these parts in mine: The mods in the first paragraph, but with an 11:1 .080 piston if you have a 300cc limit, if your cc limit is over 300cc’s go with a 330 kit or GTThunder’s 350cc kit. If you’re going with the .080 piston it should run you around 475 even give or take some and about 575 give or take some with the 300 plus CC kits.

If you bore the sleeve out to a .080 or more, I would reccomend a oil cooler. I think FST sells a kit, or you can buy a old transmission cooler from a junk yard for little to nothing and hook it up,

Next is when you have plenty of money to spend I recommend these mods: All the mods in the first paragraph. A .080 piston of your choice, I prefer Wiesco, if your limit is 300cc’s or a 330cc or GTThunder’s 350cc kit if it’s over. +1mm Kibblewhite Intake valves, no one manufacturers aftermarket oversize exhaust valves for the 300ex/250x head. You would have to have them custom made which will set you back anywhere from 100-150 dollars a piece. So I wound not worry about them. Send the head to engine builder (GTThunder, FST, TC, DASA, Hetricks, Sparks, ect.) have them port and polish it, cut the head for the +1 Kibblewhite valves, and a 3 or 4 angle valve job. Now Porting can cost anywhere from 175 to 500+ dollars, in most cases the more money, the more HP. The porting & valve work with really bring out the true power if a 300cc+ kit. I think bradly300’s was around the stock HP of a stock 450r, amazing!!!!

But when your making that kind of power you need to beef other stuff up such as your clutch, you can get heavy duty clutch springs clutch wise. Also make sure keep your chain tightened, and if it is to streached, replace it, I broke part of my case by not replacing my chain.

This is what most people that race in the Youth Production class in the National ATVA series run in there motor. This will still work fine for an everyday trail rider, but also for a national level rider to. This will run you anywhere from 800 to 1,600+ dollars. But you’ll have one hell of an engine.

If you have any questions just post here, shoot me a PM or IM me on AIM or MSN. Also please don't ask what is in my motor, I'm not going to tell, Top secrect! I hope I was a help!!!

[ZeroLogic]

should be a sticky

care to do my english report its due tommarow i have a paragraph done:macho

[hardkoratvmxr]

nice post cody. one of your better ones. lol get this a sticky asap.

[FMFTRX250r]

Good Post Cody, good reading...im looking into building a .080 over motor just like everybody else....im going with a sparks MX cam, Sparks Porting and Valve work, and 13:1 JE, 39mm FCR, sparks x-5 exhaust....along with GDH a-arms and Swinger, and ELka's...she should be a runner.......

[8my_Cash]

great post actually answered alot of questions that i have about overboring my motor. im thinking about .080 bore so i can get the 297cc motor :blah:

[bradley300]

my 350ex built by gthunder put 32 to the wheels on the high side (a bad run was 28) atvriders memeber Meek said his stock 450r put 35 out

[SidewaysSam]

Well done research

[IOWAracer]

Is FST still selling now taht mickey dunlop left cause i was going to buy a 366cc kit for my warrior and was wondering thanks guys

[Cody_300ex]

Originally posted by bradley300
my 350ex built by gthunder put 32 to the wheels on the high side (a bad run was 28) atvriders memeber Meek said his stock 450r put 35 out

Thanks for the Input brad. I was bored last night so I figured i would make a decent post for a change, lmao.

[bradley300]

lol, i understand. i liked my 300ex, but now i'm seeing what i can do with the blaster. i'm at aboutr 34 at the wheels with the stroker crank, and now we are talking about trying an aftemarket 240 cyl on top of that. 255 cc of tear jerking power:devil:

[Jonesboys]

I don't know, but my Jonesboys Racing Built 345 is pretty quick, ain't that rite Bradley, i really like it, also i had a .080 bored motor, and while i was at Hatfield-McCoy Dirtdays, it got too hot, and the cylinder sleeve warped, cracked, then the rings caught the top and set it on top of the crank. So i personally think the .080 is worthless, and it's not worth damaging you motor, if you do do it, at least put an oil cooler on it.

[Built_300EX]

There is a FST big bore kit on ebay.com. It says doesn't require sleeve, I know I would have to get it bore. However, I don't think that would be as reliable as getting the FST big bore kit on there page, that includes the sleeve. Both cost around 295.99. The pressing of the sleeve is being done by my friend that works at a machine shop. I will actually take more money if I went without the sleeve. Just reply on that. Also, I had another question. About the Big gun rev limiter, does it give the quad alot or can you even tell the difference. (last question) I plan on putting a stage 3 web camshaft, 330 FST w/ sleeve big bore kit, shaved head, titanium valve retainers and springs, hardened rocker arms, & an oil cooler on my quad. Will this make it less reliable or around the same as they originally are?

[8my_Cash]

does a .020 bore make a difference at all in power?

[Built_300EX]

Are you asking me that to be sarcastic or honestly asking the question? Can't tell right now, just by the way the post was. Sorry if I bothered you with a non-sense question, I honestly don't know.

[honda250xrider]

just to let you know sparks makes oversized valves for the 250x. you can get anywhere from +3 intake to +2 exhaust.

[Cody_300ex]

Originally posted by 8my_Cash
does a .020 bore make a difference at all in power?

Very Little.

[Jonesboys]

Hi all Jonesboys Dad here. the ..020 motor is really just a freshend up stock; you would not really notice just that. but it can't hurt . As far as that 330 kit on Ebay that says you don't need a sleeve that is BULL. 330 has to be 80mm a stock bore is74mm you can't take a stock bore to that size . those on ebay are JE pistons, JE says you must resleeve but the do not sell the sleeve; go to northwest sleeve, or get a hold of Mickey at FST he sells what you need ; so does POWROLL; Northwest will sell all the nessecary parts also. Stay away from that EBAY kit; I have emailed them 10 times trying to get a response about the claim of no sleeve ; they won't respond. or just talk to whoever will do your machine work. they can fix you up. FST does good work so does GT

[Trevor]

I couldn't imagine the power of a 450r in my 300ex that would be so awsome. Not to be a smart *** but I didn't notice any mention of cooling upgrades. It you put a 330 or 350 kit in is there any need of haveing a oil cooler and or scoops. Nice info you have there realy makes me want to make a big 300 sleeper

[Jonesboys]

if you go 330 or bigger an oil cooler is the only way to go. FST makes a Kit and so does GT or you can find some articles on mags and do it your self. air scoops can't hurt either. also the stock air diverter on a 300ex is the good to keep. we run oil coolers on all of ours. except we did not have the 1 we bored .080; big mistake but that 0.080 leaves a real thin wall I would say if you reeally needed that size i would look into a sleeve so you have more side wall. BUT for the $$$$$$ go 330 with a cam and some head work and valves. AWESOME power!!!!

[Built_300EX]

Hey, if ANYONE has a 300EX magneta puller I would really like to just borrow it. I honestly would pay for the shipping costs for it, I need it to put the bearing in on the back of it. It went bad when I had a 41 mm carb with a stock bore size due to gas leaking down into the motor from it washing the cylinder wall out. I really need this part and I would send it back the day it comes in. I could even give personal information just so you can trust me. I am running low on cash and I really can't stand ordering from the Honda shop. It costs 35 dollars from there and I don't have that. If anyone could let me us it just reply and I will give you any information that you need.

Thanks VERY much.

[bradley300]

Originally posted by Jonesboys
I don't know, but my Jonesboys Racing Built 345 is pretty quick, ain't that rite Bradley,

it moves pretty good, just think tho, my blaster was pretty close and it didnt even run right:devil: see you at the races

[Jonesboys]

yeah, that blaster HALLS!:macho

[bradley300]

wait till next year, pretty sure a 240 cc cylinder is going on top of that 4mm stroker bottom end:devil:

[bwamos]

Originally posted by bradley300
lol, i understand. i liked my 300ex, but now i'm seeing what i can do with the blaster. i'm at aboutr 34 at the wheels with the stroker crank, and now we are talking about trying an aftemarket 240 cyl on top of that. 255 cc of tear jerking power:devil:

34HP on a 2-stroke is completely differnt than 32HO on a 4-stroke, too.

Man, I love the feeling of the old 1-cyl 2-strokes.

The origional post is great. I'll bookmark it for those looking for info on 300 mods.

My only note would be that the final sentence where you say $800 - $1500 should include the note. (Not including an aftermarket header and silencer.) ;)

Also noted already. Any mods above pipe/filter/cam really needs an oil cooler.

Finally, I reccomend heavy-duty clutch springs once you get to your 4th paragraph of mods. Near 450r power on a 300ex clutch needs a little help. ;) And with this.. may want to look into an easypull clutch lever w/ hotstart lever you can use for the reverse mechanism.

[Cody_300ex]

Originally posted by bwamos
34HP on a 2-stroke is completely differnt than 32HO on a 4-stroke, too.

Man, I love the feeling of the old 1-cyl 2-strokes.

The origional post is great. I'll bookmark it for those looking for info on 300 mods.

My only note would be that the final sentence where you say $800 - $1500 should include the note. (Not including an aftermarket header and silencer.) ;)

Also noted already. Any mods above pipe/filter/cam really needs an oil cooler.

Finally, I reccomend heavy-duty clutch springs once you get to your 4th paragraph of mods. Near 450r power on a 300ex clutch needs a little help. ;) And with this.. may want to look into an easypull clutch lever w/ hotstart lever you can use for the reverse mechanism.

Thanks for the suggestions! I'll edit it right now.

[dork]

you can buy a magneto puller from dennis kirk for cheaper than $35. motion pro makes them, its really just a bolt.

[300exil]

great post ! Thanks!
just wanted to ask what about bore it to 330 remove the air box and put outwears with K&N and rev limiter...whill i need to change the exhaust ?
Thanks

[Jonesboys]

If you want to do it right get yourself an HMF pipe : a rev box; a 400ex carb ; if you are planning on riding in the woods and mud , do not get rid of the air box. get a K&N filter, and open the back of the box up or buy one of the lid top cutouts with the outer wears mounted to it. maske sure you have cam for what style of riding you are planning on. have the head work and valves done. The HMF pipes creat a lot of bottom end power . add a modified header to it it really screams.

[bwamos]

Originally posted by Moto49X
another thing. a 13:1 piston will put alot of stress on the little stock 300ex rod. Your starter will also have a rough time turning it over.

Very true. My starter has a hell of a hard time with the 330cc 11:1, lol.

[300exil]

so theres need to change the rods?

[Cody_300ex]

Originally posted by 300exil
so theres need to change the rods?

You Don't HAVE to but to be safe I would if your gunna run 13:1

[big bad beny]

Brad are you sher you can handle all that power LOL.

[gearhart.29]

has anyone ever bothered to blueprint their 400ex carb to get more flow?

[bwamos]

I doubt it would ever be necessary.

BluePrinting is the process where they add or remove material to get it to factory spec.

Heads are cast, this is where they get the large variances.

Carbs are cast.. but the center is bored, so it should already be made to blueprint spec.

[Treehunter]

Now wouldn't milling the head change the cam timing?

[countypark]

Just sell yours and buy mine. $3000

[hondardr4life]

Well I figure I'll throw my 300ex motor knowledge in here too. I have built 3 or 4 300ex race motors. First off, you must get a port and polish if you want to unlock the best power out of your 300. Second, I reccomed FST's 330 big bore kit, I have it in my 330 and it runs amazing. I would also reccomend a stage 3 web came ( I was stupid and got a stage 2). With those mods you will need an oil cooler. Now if you really wanna get crazy, go for oversized valves, and order the Sparks 345 big bore kit. Get the head shaved, and do not run a base gasket. Not running a base gasket will boost your compression a little bit. But, there is a plastic piece in you motor that the cam chain runs along. It is the one that comes out wiht the jug. If you dont run a base gasket, you will have to file down the top of the 2 little lobes on that piece so that the head will fit on tight.

[Cody_300ex]

bump this for the noobs.

[elementryder]

dose shaving the head give you more bottom end power and als does a stroker motor give you more bottom end power than a bored out engine if sow how close can you get to 300cc with the stroker

[Cody_300ex]

Originally posted by elementryder
dose shaving the head give you more bottom end power and als does a stroker motor give you more bottom end power than a bored out engine if sow how close can you get to 300cc with the stroker

Shaving the head raises the compression by decreasing the piston to valve clearance. Increases power everywhere. You would be better off just boring to 297cc on a 300ex but to get there on a 250x most engine builders do put a stroker crank in.

[elementryder]

i have a 300ex and i am going to start raceing the (13-15) class mx.i will be running up a gainst mohvies and blasters with up to 1500 inveated. here it is/400ex aarm/450r shocks/relocator kit/mxr4 18x10-9 back/mxr4 20x6-10 on +1 off set rim/rear wheel spacers/sparks x4/wiseco 11:1 76 mm piston/web racing profile cam/web shortened valve guides/web racing valve spring kit/web over sized intake valve/ if there is any other thing i need to best them please let me know . i am very good rider. alsow want it to bea reliable i weigh 195 lbs:) :) :) :) :)

[Cody_300ex]

bump for the noobs

[humblesquirel21]

are there any reliabuilty isses with the 330 kit from fst should i go with a smaller bore

[Out_Sider]

i having built many 300ex motors for me, and other people i race with, have to say that any of the overbores (.020 to .080) are all about the same. You don't really feel a difference in any. The strongest under 300cc ex engine i built had an .060 bore custom JE 12.5:1 compression piston, +2 intake valves, +1 exhaust valves(mm's), Stage 4 Web cam (.360 grind), adjustable Cam gear, Wed hardweld rockers, 2004 YFZ450 carb, HD springs w/ titainum retainers, shortend valve guides, HD cam chain, 3 angle valve job (done by me using 30 and 60 degree griding rocks) and a Head ported by me via portflow bench (find the correct air flow angles and what not) and the quad used HD clutch springs and Barnett Fibers and plates. This particular motor was used for the local drag races in the 300cc and under class. The quad dyno'ed at the track at 31hp which was considered 'incredible' by the guy dyno'ing the quad. Quad was dyno'ed w/ .125 douglas wheels and hoosier slicks and 14/34 gearing, and NO air filter (open carb).

Any questions just ask.

[Cody_300ex]

Originally posted by Out_Sider
i having built many 300ex motors for me, and other people i race with, have to say that any of the overbores (.020 to .080) are all about the same. You don't really feel a difference in any. The strongest under 300cc ex engine i built had an .060 bore custom JE 12.5:1 compression piston, +2 intake valves, +1 exhaust valves(mm's), Stage 4 Web cam (.360 grind), adjustable Cam gear, Wed hardweld rockers, 2004 YFZ450 carb, HD springs w/ titainum retainers, shortend valve guides, HD cam chain, 3 angle valve job (done by me using 30 and 60 degree griding rocks) and a Head ported by me via portflow bench (find the correct air flow angles and what not) and the quad used HD clutch springs and Barnett Fibers and plates. This particular motor was used for the local drag races in the 300cc and under class. The quad dyno'ed at the track at 31hp which was considered 'incredible' by the guy dyno'ing the quad. Quad was dyno'ed w/ .125 douglas wheels and hoosier slicks and 14/34 gearing, and NO air filter (open carb).

Any questions just ask.

Weak! lol J/k man!

[willow2679]

Anyone have pics of how to mount the oil cooler in this quad?
I think it has to be made holes in the oil pump that why I ask (to know where I can do it
And I read somewhere that this is one of the best mods to keep your air cooled engine reliable isn´t it?

[bwamos]

You dont have to drill anything.

You cut the copper tube running from the tranny up to the head.. and install the oil lines going to the cooler to each end.

[Cody_300ex]

Bump For some of the newer people, maybe QJ will run across it and sticky it....:D

[kd5sfq]

Originally posted by Out_Sider
i having built many 300ex motors for me, and other people i race with, have to say that any of the overbores (.020 to .080) are all about the same. You don't really feel a difference in any.

There is a good reason why there is little difference in power and I think I might shed some like on it. That or really put a shroud of darkness over it…

According to my calculations, there is only a theoretical difference of 2 HP between a 74mm and 76mm piston of the same compression ratio and an engine efficiency of 100%.

The majority of high performance engine builders get between 50% to 60% efficiency while only a select few are capable of 75% or higher. That boils down to only .5 horsepower difference throughout the range of efficiencies between 282cc and 298cc. I suspect nobody would notice such an insignificant power gain because it’s to small for our senses to discriminate.

Since size doesn’t matter much in this case let’s say we have a 298cc engine that we want to maximize. The theoretical maximum horsepower is 48.42 according to my math that is based on the 300ex engine design. Almost anyone can easily reach 50% efficiency with off the shelf parts and a little mechanical ability. That renders an honest 25 HP on a dynamometer which is a significant boost from the factory average of around 16 HP.

So the real question is however, how does one go about the business of boosting the efficiency of this four stroke engine that is more in line with what the top builders do? Increasing the compression ratio will net the fasted improvement in efficiency and it provides a very noticeable increase in power. Head porting to improving how the fuel and air mixes and flows in and out of the cylinder will also give a healthy performance boost.

Everyone has their own ideas. Most builders who are obtaining the highest efficiencies are not going to tell you how to eek out more power but they will build an engine for you at a price. If you are serious about engine building and really want to learn… as I see it here are two paths to take… One is learn the physics and math. The other is gain experience. Here is the rub… Experience will teach you that you need to know the physics and math…. Go figure… If you don’t believe me go try and mess with a flow bench sometime. Without learning the physics, you will feel like Alice in Wonderland.

There are lots of engine building pages on the web. A few almost go to the quantum level. So dig deep and learn all you can…

The more about engineering you know
The faster you can make your quad go!



Good luck with your engine building!

[PolarisRider]

^^^ that was a good post

[Cody_300ex]

Originally posted by kd5sfq
There is a good reason why there is little difference in power and I think I might shed some like on it. That or really put a shroud of darkness over it…

According to my calculations, there is only a theoretical difference of 2 HP between a 74mm and 76mm piston of the same compression ratio and an engine efficiency of 100%.

The majority of high performance engine builders get between 50% to 60% efficiency while only a select few are capable of 75% or higher. That boils down to only .5 horsepower difference throughout the range of efficiencies between 282cc and 298cc. I suspect nobody would notice such an insignificant power gain because it’s to small for our senses to discriminate.

Since size doesn’t matter much in this case let’s say we have a 298cc engine that we want to maximize. The theoretical maximum horsepower is 48.42 according to my math that is based on the 300ex engine design. Almost anyone can easily reach 50% efficiency with off the shelf parts and a little mechanical ability. That renders an honest 25 HP on a dynamometer which is a significant boost from the factory average of around 16 HP.

So the real question is however, how does one go about the business of boosting the efficiency of this four stroke engine that is more in line with what the top builders do? Increasing the compression ratio will net the fasted improvement in efficiency and it provides a very noticeable increase in power. Head porting to improving how the fuel and air mixes and flows in and out of the cylinder will also give a healthy performance boost.

Everyone has their own ideas. Most builders who are obtaining the highest efficiencies are not going to tell you how to eek out more power but they will build an engine for you at a price. If you are serious about engine building and really want to learn… as I see it here are two paths to take… One is learn the physics and math. The other is gain experience. Here is the rub… Experience will teach you that you need to know the physics and math…. Go figure… If you don’t believe me go try and mess with a flow bench sometime. Without learning the physics, you will feel like Alice in Wonderland.

There are lots of engine building pages on the web. A few almost go to the quantum level. So dig deep and learn all you can…

The more about engineering you know
The faster you can make your quad go!



Good luck with your engine building!

Very Good post!! Did you go to a collage or technical school to learn this kind of info?

[Cody_300ex]

Bump...

[Blue250X]

great thread, why not a sticky?? i def think it should be a sticky!! there is so much great info in this thread

[Cody_300ex]

Originally posted by Blue250X
great thread, why not a sticky?? i def think it should be a sticky!! there is so much great info in this thread

Try PMin a mod.

[quadfamily]

Good idea, this thread is worthy of a sticky.

[Chazz88]

Cody id like to just upgrade the cam, valve springs rockers and shave the cylinder head and get the 400 ex stock carb. my question is i want to keep the stock exhaust on my 300 ex... i know that sounds stupid but people ***** alot around here and we ride at night alot so will the stock exhaust work with this setup or am i dooomed.. any help will be great.. and also where would you go to shave the cylinder head? LOcal machine shop or send it out somewhere.. thanks

[2muchquad]

it would be hard to make power with a restrictive stock exhaust.what goes in must go out.the engine must operate in unison as a system for optimum performance,so a bigger carb with headwork isnt really gonna be of much benefit with the exhaust restricted.there are aftermarket systems that arent as offending as most race systems.

[Cody_300ex]

Originally posted by 2muchquad
it would be hard to make power with a restrictive stock exhaust.what goes in must go out.the engine must operate in unison as a system for optimum performance,so a bigger carb with headwork isnt really gonna be of much benefit with the exhaust restricted.there are aftermarket systems that arent as offending as most race systems.

Yep, FMF sales a system called the Q, very quiet, might wanna look into that.

[Chazz88]

k sounds goood... ill check out that exhaust sysytem

[oldfartracer]

"GREAT POST"
We have a WB-Etype muffler where can we get a HMF head pipe.
Do you have part # for the over size valves and the harden rockers,
Thanks

[TRXRacer1]

Great thread!!!

When installing the 400ex carb do you need a different intake boot or can it be fitted to the stocker? Thanks

[Cody_300ex]

Originally posted by TRXRacer1
Great thread!!!

When installing the 400ex carb do you need a different intake boot or can it be fitted to the stocker? Thanks

You'll need a 350x air boot..

[Boweman]

Is there one particular place that I can go and get all of the engine mods that I am wanting? Currently all that I have is access to the net to do my searching. I am looking into the GTTHunder's 350cc kit or the 330cc kit. I want to keep the 11:1 compression ratio and go with the .80 over with sleeve. New valves and doing some porting and polishing. A new camshaft and hardened rockers. This bike will be used primarly for woods and Hare Scramble riding so I am not giving myself any restrictions. I have been reading about different setups, but have not completely decided on which one to go with. I am a little confused about the valve selection. I have seen both the +1 and +2 Kibblewhite valves used. What is the main difference? Would it just be easier to find an engine builder and ask them to get all of the parts for me? What modifications would you recommend being done to the lower end once I start beefing the top end up? I have already taken the clutch into consideration and have that covered along with the carb and exhaust. Does anyone have a preference on the rev box?

Any info would greatly help. This will be my first engine that I have had built. I dont want to go into this build blind. Who would anyone recommend me sending this off to, to have done?

I only have the net due to the fact that I am sitting my butt in the middle of Baghdad trying to do this. So everyone out there getting the chance to ride, put a few laps down for me. Hopefully, I can get everything lined up while I am here and sent off so it will be ready for me once I get home. Dont want to delay this to long you know.

[muddy300ex]

could someone post me the link for the fst web site or where to buy the stuff and the link for that i tried searchin google but couldnt find anything

[Mx_523]

Four Stroke Tech (www.fourstroketech.net) :)

[bustedknuckle]

we went 20 over,wisco 11.1 piston.stock carb,big gun rev box. and a hmf full system pipe.its worked fine so long this year running the gncc. stock cam.

[booger]

I'm running 400ex carb wit a tc cam...and it runs just great.....i ran a 11:1 piston and it got too hot

[booger]

yea...+ pipe and rev box..and a port job............

[ssduane]

Reading in your second paragraph you mentioned shaving the head .020", and I was looking at my old head gasket and noticed its a 3 piece compositie gasket that is .027" compressed, any thoughts on removing 2 pieces and just using one thats .009", that should do the same as decking the head .020". Just wondering how the gasket will hold up afterwards. Anyone tried this?

I all ready got the engine torn down for tranny work so since I'm in there I'm all ready thinking of doing a little work here and there. Maybe the cam you mentions with springs and a +1000 CDI. Scored a wb head pipe from Motoworld for 75 bucks the other day, so figured with a slip on added and some other parts should should be funner (if I get the trans fixed).

[modifyit]

I've read post on rev limiter but still having problemes revlimiter kiking in too soon??

I have remouved all of the revers wirering and gears (for mx racing) and have an after market (hetrick) rev box + edel.carb yosh. pipe and open air box. Do you think the rev.box is a defect? or the removal of the wires?

please help thanks

[honda250xrider]

try regearing if you are constantly on the rev limiter

[modifyit]

Thanks regearing made the quad work better.

Whent back to it's original front sproket (13 vs 14) and carb.
still hitting the rev limiter but not as quick, i will try a diff. revlimiter.

[Romper444]

Bump! Bring this great thread back!