450er starting problem

[scott84]

hey everyone,

I have had my 450er for a month and have noticed a problem with starting the quad when the throttle is opened. It starts fine with no throttle, but that will hurt me in GNCC starts. I think that I read a fix for this problem on this website just a few days after I purchased my quad. I just did a search and couldn't find it.

The solution involved the two wires coming out of the thumb throttle.

If anyone can help me on this problem please let me know.

Thanks!

Scott

Someone please help him id like to know too

[Prey]

i can, those 2 wires coming out of the carb are the carb micro switch, you cut those 2 wires and solder together (on both sides to be simple)

HOWEVER..... this DOES NOT solve the starting issue with throttle, it just creates a new problem

when the the carb switch is active, it will not allow spark to the plug if throttle is added........

when the wires are cut and twisted/soldered, it will spark but......when you add throttle (and this is only my theory) i beleive the fuel added to the cylinder forms a better seal between the rings and the cylinder thus raising compression a touch.......

with that said........if you try to start the bike with throttle on, it will hang the starter........ i have yet to have a successful start under throttle since i performed this mod.

i even tried switching from the stock 6ah battery to a 8ah battery, it turned over better but would not stop the starter from hanging up

[Prey]

also, i have wrote up a tech article on how to do this in addition to some other 450ER related wiring/mods that i need to give to the admin, i will let you guys know when it is up and posted to this site

[Prey]

hey guys, here is a link to HMF that talks about jetting and richening up to solve some of the start issues......... this is one of the reasons that the HRC guys are claiming better starting......the jet/needle/AP bypass that come with the kit richen the bike up.

http://www.hmfengineering.com/forums/showthread.php?t=1310

this will not help with the weak battery/starter motor or whatever the electrical issue is


i will be trying out a 10ah motorcycle battery this week, i have concerns about the starting gears being able to handle the additional power but will let you guys know how it works out

[quadracer12]

Originally posted by Prey
i can, those 2 wires coming out of the carb are the Throttle Posistion Sensor (TPS)

you cut those 2 wires and solder together (on both sides to be simple)

HOWEVER..... this DOES NOT solve the starting issue with throttle, it just creates a new problem

when the TPS is active, it will not allow spark to the plug if throttle is added........

when the wires are cut and twisted/soldered, it will spark but......when you add throttle (and this is only my theory) i beleive the fuel added to the cylinder forms a better seal between the rings and the cylinder thus raising compression a touch.......

with that said........if you try to start the bike with throttle on, it will hang the starter........ i have yet to have a successful start under throttle since i performed this mod.

i even tried switching from the stock 6ah battery to a 8ah battery, it turned over better but would not stop the starter from hanging up

i can pull my plug out and get spark with the throttle pushed. it wont start but i have spark. i was told that it retarded the timing.

my question is do they have it where it runs better with the timing retarded and just have to advance it to get it started? so if you go and take out the TPS, will you always be advancing the timing. therefor maybe it wont run to all its ability?

if anyone knows for sure id love to know. ive hated this starting issue since i got it.

[Prey]

let me start of by saying that i am not exactly sure how the TPS works, i have heard like you that it makes small adjustments in timing to improve throttle response (i dont know if it has any effect on starting)

i have also read that the accelerator pump and a TPS work together to enhance accurate fuel metering. this makes more sense to my little brain. maybe someone on here can elaborate on what exactly the TPS does.

at any rate, i have heard C&D have some solution to the slow starting........ but this still does not cure the weak battery/starter motor issue

[Prey]

just finished testing the battery it was 14ah with 220ca, worked like a charm, would start in .5 seconds warm or cold.

it would still not start with throttle on though?? ?? ??, but it WOULD turn over and continue to, it would just not fire up...........i am getting closer :)

[Pappy]

did you use a YTX14BS Yuasa battery? thats the closest thing we could find to fit in teh stock tray but havent attempted reassembly yet.

[Prey]

no pappy, size wasnt even close, i dont have access to a huge number of batteries, so i was just going to figure out what AH and CA i needed to make the bike turn over well.

now that i have the numbers, i will look for the closest size battery and get ready to mod the battery box :ermm:

[Prey]

ps pappy, it was a 14L-A2 Champion/exide battery

[Pappy]

a 14LA2 will not give you more power..especially from exide. cheap made in china and will not meet thier own cca ratings 95% of the time. that unit isnt even sealed nor AGM technology so you would have to contend with the battery venting and the possibility that the chargiung system would over charge it severly.

ill take a subframe to work and see what i can come up with, ive got a few thousand on the shelf:chinese:

[Prey]

oh, i would not use that particular battery, again, the guy had it just about brand new, so i asked him to use it (its a replacement battery for his vfr800)

i just wanted to know if the additional amp hours and CA would make a difference in starting.

i will look for a YUASA battery with the same AH and CA as that one, plus the battery was huge and i think i can get the same power from YUASA in smaller dimensions

[kyex40047]

Prey I think you cut the wire to the carb heater. The TPS has three wires (ground, voltage in, and return voltage)
A tps works like this.
Thre is a constant voltage coming into it. As you apply the trottle, it rasies the resistance and less voltage is returned. The computer can tell were the throttle is, by how much voltage is returning. The more throttle you give it the more the computer advances the timming. That is just the basics.
Like I said before, it sounds like you cut the wire to the carb heater.

[Prey]

nope not carb heater, turns out after talking to colby at c&d, wasnt tps either, it was something else that is a safety, but it does allow the bike to fire under throttle

[WhiteZee]

Originally posted by Prey
nope not carb heater, turns out after talking to colby at c&d, wasnt tps either, it was something else that is a safety, but it does allow the bike to fire under throttle
i think it would be best for everyone if you stopped posting about this. you have no clue what your talking about. i hope no one tries to cut their tps wires.

[Prey]

i did call the micro switch by the wrong name...... thats my bad.......... for the rest of your comment...........if you were shooting for *******, you nailed

[Dave400ex]

The HMF post is very good. When you cut/solder the two wires together inside the carb like they show, do you still have to disconnect or mess with something at the throttle?

[Prey]

Originally posted by Dave400ex
The HMF post is very good. When you cut/solder the two wires together inside the carb like they show, do you still have to disconnect or mess with something at the throttle?

ya, there is a sensor in the thumb throttle, follow those 2 wires under the hood and unplug them from their cannon plug.

[4ABURN]

Timing makes a big difference on starting, I have seen on some high compression motors 2 and 4 strokes (alot of hill climbers short runs) that have a switch on the handle bars for 2 timing curves one for starting and soon as it starts flick the switch. But I would not fool with the TPS on the trx it is telling the computer where the throttle is at ALL TIMES not just at starting.:D just my 2 cents.

I think we are looking at just a bunch of bad batteries.Any one with a good battery does not have these problems.:)

[QuadRacer041]

[QUOTE]Originally posted by 4ABURN
Timing makes a big difference on starting, I have seen on some high compression motors 2 and 4 strokes (alot of hill climbers short runs) that have a switch on the handle bars for 2 timing curves one for starting and soon as it starts flick the switch. But I would not fool with the TPS on the trx it is telling the computer where the throttle is at ALL TIMES not just at starting.:D just my 2 cents.

I think we are looking at just a bunch of bad batteries.Any one with a good battery does not have these problems.:)





prey was just calling the part by the wrong name its not the tps, just a micro switch that tell the cdi/computer that the sllide is open, its purely a saftey item.

[4ABURN]

OK cool thats good.:D Just trying to help didn,t want anyone to hurt there quad.:ermm:

[Prey]

4ABURN,

i also have the TPS disconnected, unplugging the TPS just assumes the WOT timing curve, i have read that natalie and wimmer are both running their bike with the TPS disconnected.

[4ABURN]

the CDI or computer will just default to a less advanced timing curve if there is no input from the TPS,no biggy I guess. Sorry for any hard feelings.:cool:

[kyex40047]

Originally posted by Prey
4ABURN,

i also have the TPS disconnected, unplugging the TPS just assumes the WOT timing curve, i have read that natalie and wimmer are both running their bike with the TPS disconnected.
It would run like **** if the timing was advanced for w/o all the time. So thats not true.

[Prey]

na, it runs fine, when i get a chance, i will dyno it with and without the TPS connected

[Prey]

here are some pics of bypassing the micro switch so your bike will fire under throttle, also you must follow the wires out of the thumb throttle, under the hood and unplug them from their cannon plug

this pic is a little small, but the 2 wires that run into the carb above the idle speed adjustment and throttle cable are the ones to look at

http://i27.photobucket.com/albums/c156/kstanka/DSC00714.jpg

[Prey]

http://i27.photobucket.com/albums/c156/kstanka/DSC00715.jpg

[Prey]

http://i27.photobucket.com/albums/c156/kstanka/DSC00716.jpg

[Prey]

http://i27.photobucket.com/albums/c156/kstanka/DSC00717.jpg

[KRMit]

I don't guess it matters, but why bother soldering the wires together that come out of the carb? That's just a switch and the wires shouldn't matter anymore if you cut them.

[Prey]

Originally posted by KRMit
I don't guess it matters, but why bother soldering the wires together that come out of the carb? That's just a switch and the wires shouldn't matter anymore if you cut them.

i soldered them all the way to the plasticwire coating on both sides just to make sure no moisture or dirt found its way up the wires, so when i sell the bike i can recconect it and be fairly confident i wont have issues.

[kyex40047]

If the computer thinks it is w/o, it is going to send the spark too soon, when the motor is in the low rpms.

[Prey]

you should go read some of the threads on it at thumper talk, dirt bike guys have been going back and fourth over it for years along with the yfz guys

[kyex40047]

well considering I just got done taking auto electronics, and we learned a lot about 3d ignition and TPS, I think I have a pretty good idea of how it all works.

[Prey]

you should go look anyway, there are some dynos over there to back it up for the yz motor

im not saying anyone else should do it, but i did and i wanna dyno both ways so i can speak with fact instead of guess.......is that cool with you........

[prepracing]

has anybody heard anything about putting a Hotcam in the 06' making it even harder to start than before ? I know someone that done this and their's will sometimes not even start when being pulled off :confused:

[Dave400ex]

So you just have to solder the 2 wires at the carb, and unplug the wires coming out of the throttle under the hood? You don't have to cut/mess with the wires actually inside the thumb throttle?

[kyex40047]

Originally posted by prepracing
has anybody heard anything about putting a Hotcam in the 06' making it even harder to start than before ? I know someone that done this and their's will sometimes not even start when being pulled off :confused:
they most likely have the cam timing messed up.

[kyex40047]

Originally posted by Prey
you should go look anyway, there are some dynos over there to back it up for the yz motor

im not saying anyone else should do it, but i did and i wanna dyno both ways so i can speak with fact instead of guess.......is that cool with you........
Go for it, But its already been done.

[Prey]

Originally posted by Dave400ex
So you just have to solder the 2 wires at the carb, and unplug the wires coming out of the throttle under the hood? You don't have to cut/mess with the wires actually inside the thumb throttle?

no, you can leave that switch in place as long as you have unplugged it under the hood

[Prey]

Originally posted by kyex40047
Go for it, But its already been done.

do you know where the dyno sheets are? that would save me a few $$

[kyex40047]

trx450r.org there is some thread where this was being dicussed. I am not for sure which one it is. I will try and do a search.

[Prey]

thanks man

[WhiteZee]

http://www.trx450r.org/forum/index.php?showtopic=11954&hl=ignition++timing