Hi guys

Got my yfz500 running smooth ... but only with a few problems that i think could be easily solved ...

first , the bike smokes like a two stoke except at a very high rev then it stops completely , the engine is laying a lot forward could this be why it smokes , i had the head off once and the bore was still good but it had the normal wear since its a 92 .

second , is the exhaust header suppose to get hot (very) at a cruise in 4th ? almost burned my skin off my leg today. And if it gets so hot is it lean or rich ? and which way does one turn the screw to tune it ?

third , when i felt the exhaust get hot it started spluttering at low rev , if i kept it in a high rev it would keep running , i thought it was broken so i let it cool down and about two hours later i started it up and it ran fine , apart from the smoking , anyone got some ideas ?

fourth , the engine sweats a bit through the head gasket and when the drop of hot oil hits me it burns like hell , i also installed a oil cooler and it really helps the engine temp

and fifth , i got the engine in a yfz 450 and i am sometimes a bit lazy to shift , so does anyone know of any high performance automatic engines ? I wold love to have another project !

I can post pics if necessary
Many Many thanks !

how many miles are on the bike? sounds like the cam chain could be in need of replacing that is why it is getting hot and when it gets hot with the timing advance it idles off. do you hear any slapping or pecking noise in the top end. lean/rich adjustment will cause it to run hot but I wouldn't think it would be that hot. by the way you are in the honda forum and your yfz500 is a yamaha.

electric outlaw, on 28 January 2012 - 12:09 PM, said:

Thanks for your reply ,I don't know how many miles are on it becuase I bought the engine without the speedo The chain still looks good and is at a good tention and I hear no noise only at a rev but it comes form the flywheel side I was rold that it is the ballencer chain ,but I had it sorted out but still makes a bit of noise ,could it be the timing what could cause this heat from the exuast headers ? ,The temp felt normal at the engine , it was just the headers that almost got red hotAnd it didn't idle off , it started backfiring and spluttering Oh and the yamaha thing , its a yfz 450 with a xr 500 engine .Thanks

Any one else with opinions ?

there was another thread on here of the same thing with a video of the header vetting red for the heat. you can search it for the cause I think he had a couple of things wrong. yfz 450 with a xr500 motor we need pics of the machine.

Thanks electric outlaw ,will be posting pics on the weekend ,was riding the bike today and it did the same thing , when it heated up at the header it cut out at loww revs luckily I was going at speed and could drop gears to get it running again but it splutterd until it got to very high revs ,it cut out completely at the end of the road and I gave it about 2 minutes and I started it up normally and it ideld nicely ,it got me to my gate and it cut out again ! ,same thing cut out at low revs, let it stand a bit more and I could start it again to drive it to its garage , can someone please help with this problem I am really puzzled ! , thanks

Exhaust headers get hot full stop. No way are you ever not going to burn your leg/hand should you touch them. There is no such thing as a 92 XR500..they didn't get built after about 1984..Your engine is the same as an early model twin carb RFVC XR600 barr bore and Piston size differences., If it's smoking like hell it needs a rebore with new Piston and Rings added and or Valves and valve guides doing and valve seals replacing., The cutting out may be a poked CDI or a poked ignition coil or some problem with the ignition wiring coming from the Stator,,ie,,(a short)..,,and or maybe a problem with the kill switch,,

I can't begin to guess what the problems are without more information on wha the engine actually came from. As Horri said, there was no XR500 after the '84 model year, at least not an RFVC. The GB500 street bike, however, had an RFVC 500 and was built for a few years spanning the very late '80s and early '90s.

1.) Is it a dry sump RFVC engine?
2.) What numbers are cast into the lower right (clutch) side of the jug?
3.) Two carburetors or one?
4.) Jetting?
5.) Regarding the header, how hot is "very hot" to you? Glowing is not good, but all bike headers are going to throw a lot of heat, twin-primary aircooled singles like an XR especially.

HeadTrauma, on 01 February 2012 - 09:22 AM, said:

Hi ,I can answer all of them , 1 .its a wet sump ,I don't know what head was on it but I now have a xl 500 head on it , they say it increases performance2 PE01E51095423 its a single carb , note xl head4 stock jetting5 its not glowing it just gets hot (maybe not very hot becuase I was wearing a shorts , but I had to keep my leg at least a rulers length away)

Sounds like it has a 79-82 XL/XR/FT500 motor in it,,Still who can be sure without a picture.,Headers get hot as HT said,,So long as they aren't glowing red I wouldn't be overly concerned,,Be more concerned on what angle the engines sitting in the frame regards oil delivery,,Still,the old 500s used to be wheelied for miles in a one wheelstand fashion running right through the gearbox while up from 2nd to fifth along beaches/roads down here in a vertical position and never seized so you may be ok,,

Hi
I will be posting pics at the end of the weekend,but I can tell you that its mouted aat a angle that is opposite to a wheelie , like wwhen front brakes is applied and tthe whole bikes rear end is lifted up ,can that result in it smoking ?
And does anyone have any clues about the sudden spluttering ?
Thanks

hi guys
pics as promised

http://s1130.photobu...et_action=album

http://s1130.photobu...nt%3Dyfz500.jpg

thanks

Yup, that's a pre-'83 engine.

Interesting project.

Anyone got some clues about the problems ?
Thanks

Not really..It's a hybrid so who knows whether the oiling system and everything's ok.

The spluttering could be anything,,Ignition coil or CDI or maybe an intermittent
electrical short or possibly something to do with the heat of the engine and gas delivery.
Sounds to me like it needs re-jetting as well,,What's the plug look like after an average ride??.
No points in those engines so that's out.
Smoking is as has been stated previously.

It has something to do with the heat , because just as it starts getting hot it starts doing it , is there any suggestions about it ? Thanks

Ok , let's leave the xr 500 out ill find a solution , but another question , does anyone know of any high performance AUTOMATIC engines ? Kind of like the kawasaki kfx 700 . Thanks

Bump

Guys , please help me !
I need to have a possible solution so I can ride the bike , my dad says I can't ride it only if I can find out what's wrong and get it running 100% . We know that the problem could be linked to the heat of the engine
Thanks