[Trudeau89]

Hello all,

2009 Honda CRF250r
JD Jet Kit
Quickshot 2

Lex .12 Rex.12
Lin.05 Rin.06

I am looking for advice, knowledge and everything else that can help me get to the bottom of my current random difficult starting issue.

I will try to give as much info as possible to help diagnose the problem but the long story short:

Bike starts well cold with choke.
Bike randomly doesn't like to start when warm and or hot, but not all the time.

For example on Sunday bike starts fine at the truck, waiting on the line for practice for a few moments then takes 15-20 kicks.
-starts fine the next two races, once hot after tip over in corner.
-3rd race have to bump start it on the line, tip over in corner on lap 2 wont start DNF

Aggravating......




My thoughts/ additional info:
I have raced the bike for about 3 seasons, had the bike completely dialed for first 2. Late in the second season started getting bad bog and kept turning the fuel screw in until I exceeded minimum range. Took the carb apart during the winter checked float level, replaced needle and diaphram. Still terrible bog. Had the bike evaluated by a shop and they switched out the jet. bike since is running good on the track but started giving me slight troubles starting. Bike now is acting up much more regularly.

Also the valves are within spec but I have 72 hours on the bike and have yet to have to adjust them.

I'm wondering if there is some mysterious carb issue I can not determine or if it something valve related.


If I can not come up with any ideas or solutions soon I am going to take the carb off my brothers bike (stock 04) and see if it the issue continues. Unless someone else knows of something I am missing. Running out of ideas and patience on and off the track......



Thank you in advance.

Anhy more info needed or additional questions feel free

[Trudeau89]

Here is the link to my post concerning the 'bog' issue at the end of last year...

http://www.crfsonly.com/forum/viewtopic ... highlight=

[crfsonly]

have you done anything with the carb? if so, list what you've done. areas of interest: hot start system, floating valve plate/seal, AP diaphram.

ken

[Trudeau89]

have you done anything with the carb? if so, list what you've done. areas of interest: hot start system, floating valve plate/seal, AP diaphram.

ken

Over the winter I took the entire carb apart cleaned everything, blew out the jets. Had the float level checked replaced the steel rod that pushes the diaphram, replaced the diaphram along with o rings.

Hot start system I have only removed and cleaned.
Floating valve plate cleaned, no new seal.

[crfsonly]

check the floating valve plate and seal and make sure they are installed correctly and the seal is in good condition. check the AP diaphragm and make sure it is installed in the correct orientation and that the o-ring and d-ring gaskets are installed correctly. also check the AP is delivering a strong squirt. replace the pilot jet just to be confident there are no issues with it. also, removed the emulsion tube and verify it's in good working condition.

we have how-to in our how-to area for the floating valve plate/seal and the AP.

after you do the carb work verify the hot start cable is seated and hot start nut is install and not broken.

also, any history of engine damage?

[Trudeau89]

Taking a look at those forums now, thanks.

No history of engine damage, the only other issue I have had is increased fluid in the crankcase breather hose but that has since resolved itself after getting the bog issue under control.

I know valves being out of adjustment can cause hard starting problems. Mine are within spec so does that mean we can completely rule out that option and know that it is something carb related?

[crfsonly]

if it's not the valves the next likely place to look is the carb.

[Trudeau89]

One more question to ease my curiosity.

Is it normal to have to ocassionally re jet carbs that were dialed in, to address bog issues when no other bike changes were made.

Just wondering if when we figure out what is causing this problem if it is also cause for the development of the bog issue last year.

[Trudeau89]

Just started removing the carb.

It appears the hot start threads are stripped



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[Trudeau89]

also, removed the emulsion tube and verify it's in good working condition.

?

What specificaly are you looking for when inspecting the emulsion tube

[crfsonly]

replace that hot start with the Zip Ty version we offer. make sure the emulstion tube is clear of any deposits/debris and is fully threaded in place.

[Trudeau89]

AP looked good, O rings good.
Valve seal look to be in good condition.
Emulsion tube free of damage.

There was a bit of blue/green coating on some of the o rings and emulsion tube. Wiped it clean.

At this point I think I am going to re install everything and hope that the hot start was the issue.

Unless anyone has any other suggestions before re installation.

[crfsonly]

let us know how it goes. should not be any coating on the emulsion tube or the o-rings.

[Trudeau89]

Update.
New hot start not solved the tough starting problem. 100% improvement starts up without the hot start when warm/hot, otherwise ye hot start works.
Only set back is now the bike isn't running as great any more (bog came back) Got it running acceptable prob about 90% Ill have to keep messing with it I'm wondering if I should go back to my original settings...

[crfsonly]

that's progress. now look at the fuel screw, pilot jet and the AP diaphragm. make sure all of these are perfect working order. the pilot jet may look clear but can be partially obstructed and this will have a negative effect. check for strong and long AP squirt.

ken