Question about 2002 Honda CRF 450 R

1 Answer

It just began smoking a bit,hope new std. top end can apply.

Looks as though the carbs float seat took a dump and flooded into the motor oil from what i smell.As soon as i saw the puff of white blue out the pipe i took it out of service @ 80 and a hair hours showing.I tore it down for inspection and found the cylinder is true top to bottom within .0008'' and clean,and the valve guides pass also. , With new std piston specs to what the bore is at, a snug .002'' is what i have.So first: what are the recomended service specs for piston to cylinder wall? Second:What does Honda grant for the top, second, and oil ring end gaps (if at standard bore)?

Posted by on

  • 1 more comment 
  • Wall Billeaud
    Wall Billeaud Jul 25, 2009

    Please excuse me,I was requesting tolerances,not put it back together with a scuffed p. skirt and obvious ring wear,you seem such an intellegent fella,so forgive me if you would dear sir .I is jus so we todd did,with my top certification on very many makes and all the models under each,for a bit over 35 years. Just looking for the specs from good 'ole Honda on this model.So hey, when you get stumped,get with me and i'll be glad to inform & get you goin by diagnosing the root of a problem with all the needed facts and info to help keep down alot of your uneeded trial and error waste of time :)!sorry you do not know these specs either.

  • Wall Billeaud
    Wall Billeaud Jul 26, 2009

    I Was Totally Wrong for that ,I Must Admitt. And Yes I do happen to have a Zone litterally rite next door to my home ,and i sure did'nt know they had anything but vehicle info,thank you a bunch, kind sir,i'll walk over and see.Peace to you and yours,wallace.

  • Wall Billeaud
    Wall Billeaud Jul 26, 2009

    how did you figure miles for amt. of hours?I thought that was really neat,whats the formula?



1 Answer

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points


    An expert that got 10 achievements.


    An expert that got 5 achievements.


    An expert whose answer got voted for 500 times.

  • Honda Master
  • 3,433 Answers

You opened the engine for a ouff of smoke at roughly 48,000 miles? A bit premature for a honda. Yes, ring end gap is necessary. Put it back together and change your oil. Finding out where the gas came from should be your concern. Sorry.

Posted on Jul 25, 2009

  • Ned C Cook
    Ned C Cook Jul 25, 2009

    did'nt mean to upset or insult you. I searched references I have on hand but ,nothing on the 450. Where are you located? If you have a autozone around you, They carry Clymer repair manuals for cars and bikes. The specifications tables are very comprehensive. . zGood luck.

  • Ned C Cook
    Ned C Cook Jul 26, 2009

    No problem wallace, The formula isthe average now of 60 mph x the number of hours. You said 80 hrs so, 80x60 is approximate mileage equivalancy.I wasn't aware of the scoring and skirt issues or it would have been a stand down for me, because if I can't see it, It would be wrong to advise ignoring. I hope you found the references you needed. Depending on the wear and severity of the scoring, You may end up buying a new cylinder kit. You know how to mic out all the tolerances, so I wish you luck. All is good, just a misunderstanding.



1 Suggested Answer

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

A 6ya expert can help you resolve that issue over the phone in a minute or two.
Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
The service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.
Good luck!

Posted on Jan 02, 2017


Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer


A) I didn't know Yamaha makes a Desktop PC.

B) So far, I don't know of any desktop computers that use an internal combustion engine, and use a fossil fuel to run it.
Hope not because this is going against the grand scheme of things, lol!

C) Fresh top end, and a carburetor fuel induction system; plus flooding out?

1) Float level is set too high.
Readjust level. Worked fine before top end job?
Maybe it got bumped.......umm, like dropped.

Carb was rebuilt too? Float level is not correct.

2) The tip of the float needle is Neoprene. As such it can be damaged from a fall.
It can also be deformed from having too much pressure applied to it, when installing.

3) Float needle seat has come loose from carb main body.

4) Float needle seat is damaged. Tightened too tight, etc.

5) Junk in fuel tank has made it's way into between float needle, and float needle seat.

6) Float needle hair spring clip, was not properly installed on float.
(If used)

7) Carb was Not rebuilt, has sat while top end was done. This took some time, like weeks, months, to get too.
All the cr@ppy additives in the gasoline, has collected in the float bowl; and causing float needle to not set correctly in float needle seat.


(Now watch. You'll come back with a voice like Stimpy, and state;

"joecoolvette, you stink-ing idio-t!
I was referring to my Yamaha desktop computer. It's spraying gas out of the carburator. You have no idea of what you're doing.

Signed, Stimpy)

Mar 26, 2013 | Computers & Internet

1 Answer

When i start the lt1042 cub cadet riding mower it smokes from the exhaust and oil is in the carb

sounds like the needle valve inside the carb has failed dumping gas into the crankcase and into the cylinder this overfills the oil and dumps it change the valve and seat change the oil a couple times add a fuel line shut off and run the carb out of gas when your done using it the newer fuel we get melts the rubber seal

Apr 25, 2012 | Cub Cadet Riding Lawn Garden Tractor 25hp...

1 Answer

I cleaned the carbs it ran great for 10 miles and then began flooding.replaced the gross jets in float bowles. ran good but had to pull of carbs again to fix float bowl leaking now it floods so badly it...

Sounds like you need to check the needle and seat for dirt etc. or one of your floats may be sticking. A simple way to check is to connect the fuel pipe to carbs upside down with float bowl off and you will see if it is leaking or not. If that is ok then make sure that the floats are not sticking or holed. Test again by inverting the carbs again with no fuel in them and you should not be able to blow into the chamber until you turn the carbs to normal position. Hope that helps.

Sep 24, 2011 | 1989 Yamaha YX 600 Radian

1 Answer

Virago 250 ran good until last parking. then, about two weeks later, what looked like a gas/oil blend began pouring out of the breather when cranking. engine would not start. removed carb and replaced...

Check you oil level first and foremost, sounds like your bike IS flooding. When you replaced your float needles did you inspect the seats they sit in?? if they have a nick in them they wont seal and flood. remove the carbs and bench test them. you may need to lap the seats if they are nicked if you need to please contact me and i will give you step by step on that part.
Good luck

Apr 19, 2011 | Yamaha YZ 250 Motorcycles

1 Answer

I have a Craftsman Yard Man 6.5hp push mower with a Briggs & Stratton engine. The engine starts and runs fine for about 30 seconds or so then slowly dies out. It turns over slower and slower until it...

Have you checked the choke that it is off after you get the engine started,the black smoke is definitely from the choke, if you take the carb off and check that the needle closes when it should,as one can easily do an adjustment by bending the float/tab,rgds

Sep 25, 2010 | Briggs & Stratton Garden

2 Answers

12hp brigg & stratton engine gas mixing with oil in engine block..when start engine runs high rpm can not idle & look like gas come out carb air cleaner overflows & flood out & stop engine...

Sounds to me like the float needle valve in the carb is leaking. This will cause fuel to over flow out of carb, and will even get into the engine oil. Check to be sure that float is not got gas in it the can go bad. Also check float adjustment. Check needle and seat very carefully for dirt or wear. Just the slightest bit of dirt or wear can cause it to leak. Hope this helps.

Sep 17, 2010 | Parks Optical 13.5hp Briggs And Stratton...

1 Answer

There is smoke coming out of my lawnmower

did you check oil level . what happens is the carb float sticks and dumps gas into the motor crank with the oil,(oil will smell like gas) to much oil = smoke.(rebuild carb change oil). IF this is a bad or weak motor use STP OIL treatment the thick stuff and use the whole can when you do your oil change . this will help you sneak a year or two more out of a bad motor

May 21, 2010 | RTO Husband on Lawn Mower Whirligig

1 Answer

LT 1000 flooding gas out muffler and stalls, then pours in carb.

Check your oil. Does it smell like gas? If so, don't run it even if you could. You will fry your engine. The float needle and seat in the carb are leaking. In other words, the float needle is not shutting off the gas when the bowl is full. You need to have them replaced.

Jun 18, 2009 | Craftsman 17.5 hp 42 in. Deck Lawn Tractor...

Not finding what you are looking for?
2002 Honda CRF 450 R Logo

166 people viewed this question

Ask a Question

Usually answered in minutes!

Top Honda Experts

Arnie Burke
Arnie Burke

Level 3 Expert

4736 Answers


Level 3 Expert

78267 Answers


Level 2 Expert

342 Answers

Are you a Honda Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides