I have a 98 TRX300FW that just wont crank when cold. I took the bike to the repair shop and they said the CDI was bad. He pulled it out and warmed it up and the bike cranked. Then he took the box and froze it and after reinstall the bike wouldn't crank. He did this a few times to confirm his suspicsion.

My problem is no one has a CDI box in stock. EVERY place I call says it's on national backorder. Here's my two questions. First, could this problem be something else besides the CDI? It seems that if the box was bad it wouldn't crank at all or when it was hot, not cold. Secondly, if the box is bad, do you know of any places where I could purchase one? It's been down for over 3 weeks now waiting on the part and I really need this bike up and running. I know several places sell CDI boxes that improve power but that's not what I'm looking for. I'm looking for one that PRODUCES power! lol

Someone suggested the valves may need adjusting. Could this cause this problem?

Thanks for the help. I'm a bit new to this.

 

Never heard of that myself. I would think just the opposite would happen meaning that if it got hot it would shutdown. Most solid state devices prefer cool temps to work properly. Try blocking all the vents on your pc and see how long it runs before it shuts down from heat.
That's my opinion.

Dennis Kirk lists a replacement CDI box for that machine in their catalog.

 

electronic modules can fail from cold too, i see it all the time with cars. the cold causes things to contract and circuits to open up, etc.

BUT, my question is this- when you mean it doesnt "crank", does that mean the starter doesnt engage and turn the engine at all, or do you mean then engine cranks over, but doesnt actually start? When you say it doesnt crank, to me it sounds like the engine physically doesnt move when you go to start it, and doesnt really sound to me like CDI, as the CDI just controls your ignition and advance. It would be your starter button, relay, battery and starter motor to look at.

but if it's cranking over, but not starting (not firing up) then yes, it's a good bet you have a bad cdi box, since it controls the ignition system.

 

He will have to confire this i know , but it sound's to me he meant it turn over the engine but just wouldn't fire when cold ; i could be wrong though just what i got and i have seen this on other brand quads with the same symtom's ! ...............williebee

 

I should have been a bit more clear. It will turn over until the battery dies, as it did on me yesterday. If you warm up the CDI box then reinstall it, the bike will fire and run fine. Let it sit over night, even if the temps don't get that cold, and it will not fire. It just turns and turns and turns.

Now the problem is I can't find anyone that has this box in stock. It's hunting season here and I need this thing running. I thought by getting it to the shop a few weeks before the season began I would have been fine. I guess I was wrong. My option now is to bring the CDI box in the house with me and only install when I get ready to crank it. Then I would have to remove it when I get to my stand and take it with me to keep it warm. Man what a pain!

Someone (outside of this site) suggested the valves may need adjusting and could cause this. Is that possible? Still doesn't explain why the thing fires when you warm the CDI box. I'm just trying to figure this thing out in my head I guess. I've worked with electronics for almost 10 years and it doesn't make sense that it's fine when warm but not when cold. Of course I didn't think about the cold making it contract and open circuits.

Thanks for your suggestions so far but if you have any more please send them my way.

 

Sorry man but if it was just the valve's needing adjusted that wouldn't cause the CDI firing problem ! I've been a small engine tech over 20yrs. so i can say for sure this wouldn't be the fix ! If it was the valve's it would be hard to start warm or cold ! I could suggest warming up the CDI with a small propane torch , but you would have to be very carefull about not heating it up to fast , you could fry it if you weren't very carefull doing this ! You could try it at home first , and might get by untill you can get a new CDI ; it would be safer using a hair blow dryer but this wouldn't work out in the wood's with no electic outlet's handy ! Or if you had a cordless hair blow dryer this would be perfect , but i don't know if they even make a cordless hair blow dryer. Wish i could think of something else but i just can't think of anything offhand ! ...............williebee

 

yes, valves probably not it. Yes, it may cause a hard starting issue, and it may run like crap, but they would have to be WAY out of spec to not fire at all.

I guess to be sure it's the cdi, let it sit out cold and remove the spark plug first thing and see if it has spark when you try to start it, if no spark is there, it's probably the cdi.

as for finding one, well, you're on your own. You could try ebay for a used one, might get lucky.

good luck

 

Ive never seen a cdi fail when cold but good when warm. This might be a first but i doubt it.
Check the intake valve for being too tight. The first sysmtom of tight valves is hard to start cold.
To confirm the cdi is good, do like quicksilver suggested...put in a spark plug, and ground it out...crank and look for spark when cold. My guess is youll see spark, then do the valve adjustment.
If the valves are good, check the enrichener sircuit of the carb for proper operation. If the motor is warm...and you pull on the choke...does the motor run badly or die?
Ebay usually has one or two of the cdis for sale, at any time.

 

Thought I would give an update on the situation. I brought the bike home from the repair shop because I needed it this past weekend for deer hunting. I had to charge the battery back up to full since it was drained earlier by trying to get it to fire. I brought the CDI box inside with me so it would stay warm. I loaded up everything and headed for the woods with the bike on the trailer and the CDI in my shirt pocket. When I got to the woods I plugged up the CDI and it fired on the first revolution. Ran like a champ as best as one could run when the temps are around 35. When I got to to my stand I removed the CDI box and put it back in my shirt pocket. I did the same thing when I came down for lunch. Plugged it back in and fired right up.

Well I started thinking, what if it was the battery that was causing the problem. I wasn't ready to test anything since I was returning to the woods that evening. Well, I got back to the woods and repeated the same process and didn't have any issues. When I loaded up the bike to come back home for the night I left the box attached to the bike. After my 30 min ride back home I went to unload the bike and store it in my building and it would not fire. I brought the box in the house while I ate supper then went back out and tired it again and it fired right up. It must be the CDI box. I've ordered one from a company online. Once I get it, hopefully today, I will install and let you know if it worked or not.

Thanks for all the suggestions.

 

we will be waitng to hear how everything turn's out , and i'm sure the new CDI will be the fix that you need and i will keep my finger's crossed ; and keep you all in my prayer's ! If you get a deer take some photo's to share , hope you get a trophy buck and meat for the freezer ; it's been a few yrs since i've been hunting myself the last deer season for me was 2001/2002 season ! I used a new Thomson Center GreyHawk 50 cal. saw over a dozen good buck's they were all out of range for a sure shot , but i got a massive 8 pointer dec. 3rd with less than 150 feet ; it was kind of scary at such a close range if i hadn't gotten him he would have gotten me ! I was on the ground between the buck and a dozen does i had called in with a Loman grunt call with Tinks No.9 on my leggin's , this is the most heartponding extreme style of Big Game Hunting i've ever used in my life ! All my bud's thought i was crazy using this hunting style with me being a Bilateral Amputee , both leg's off at the knee's since a auto accident back in 1975 at the age of 21 ; but this was my best chanch at getting a deer in the area i hunt in NorthWest Ga. and it payed off for me big time ! Have a good season to everyone on the forums.............williebee