300ex problems

[andyyurko]

I just rebuilt my 300ex a few weeks ago. I broke it in and it was running like a champ for a couple weeks untill the last ride. It had a hard time starting up (it was pretty cold out but nothing unbearable) and whenever i would top it out in 5th gear it would start bucking and loosing power. It seems like its either loosing spark, misfireing or not getting enough feul. The low and mid rpm's are fine and it has tons of bottom end. Thers a wiseco 13to1 piston in it (.08 over), new cam and rockers, and a new clutch. I was running 93 in it while breaking it in but it would run pretty hot so for this ride i ran a mix of clots and premo, about 3 klotz to 1 premo. Do you have to adjust the jetting when you run klotz? Or could it be the valves, timing, etc.


any ideas would help

Thanks

[redrunner]

Sounds like you are hitting your rev limiter...

[pimpin330ex]

hows your plug looking for color

[bwamos]

1st switch back to 93. New fuels will usually require a rejet. Different concentrations of fuel to additive ratios. More additives = less fuel per ounce = lean condition.

If it is that you need to bump up your main jet.

If it's not that..
The 300's CDI thinks it's in reverse.

Clean the connection behind you're foot brake. Under the sheet metal cover theres to wires connecting to studs on the case. Remove them both, clean them up, and reconnect.

The one Marked R is most likley a little corroded and causing your reverse limiter to think it's in reverse causing you to cut out at about 60%. Get's that hard rev bounce going. Use electrical contact cleaner.

If you clean that connection and it is still doing it, you need to clean up the connections in the big wire harness connector in front of your motor just above your coil. A real pain to get apart.. so don't get too frustrated.

[andyyurko]

il give it a shot

thanks a ton for the info

[Sjorge450R]

check the electric, but you say your runnign a 13:1 piston. I didnt even know they made one otherwise I would have chosen taht for my motor. if it si a 13:1 you need some sort of 50/50 mix fuel. Dont over do the race gas tho.

[bwamos]

I beleive he's running a mix of 2 race fuels, no?

[andyyurko]

Im running 93 pump gas mixed with klotz 113.

[400exrider707]

The cold itself could have simply affected your jetting.

[andyyurko]

when i go home this weekend il check the plug to see what it looks like, il also clean up that reverse plug. Il let yaz know how it goes and thanks for the ideas.

[Kaleigh]

Originally posted by andyyurko
I just rebuilt my 300ex a few weeks ago. I broke it in and it was running like a champ for a couple weeks untill the last ride. It had a hard time starting up (it was pretty cold out but nothing unbearable) and whenever i would top it out in 5th gear it would start bucking and loosing power. It seems like its either loosing spark, misfireing or not getting enough feul. The low and mid rpm's are fine and it has tons of bottom end. Thers a wiseco 13to1 piston in it (.08 over), new cam and rockers, and a new clutch. I was running 93 in it while breaking it in but it would run pretty hot so for this ride i ran a mix of clots and premo, about 3 klotz to 1 premo. Do you have to adjust the jetting when you run klotz? Or could it be the valves, timing, etc.


any ideas would help

Thanks

you're probably running rich.. drop down jet sizes til it goes away..

[250X_project]

Originally posted by Kaleigh
you're probably running rich.. drop down jet sizes til it goes away..

Just don't be drastic. Too lean is worse.

Maybe the rev limiter is lower than meant to be, because of a faulty CDI.