[madhondalover]

i have a 1998 honda 300ex and just put in new rings. has a big bore kit in it. timing is right on and no odd noise when idle. fires right up and sounds great again but for some reason it will only rev half throttle and then revs out. all power is gone at that point. need some help i have tried going one tooth back on the timing and goin on tooth ahead and does not change,.any if would be great.

 

[Helmut]

Welcome to the forums. Did it just start this after installing the new rings and was it already running right with the big bore kit before?

 

[TRX2fiveO]

Agree^^^^^ also the valve adjustment may be off maybe too tight? check your choke lever too

 

[madhondalover]

the big bore kit was already in there when i got it and i have checked the choke if the choke is at half or full still does it. i have started going threw the wires. and have not found any losose or broke yet.

 

[madhondalover]

o and the valves are at stock.

 

[jgar]

Has the carb been cleaned?

 

[TRX2fiveO]

yeah clean the carb especially the jets and their seats

 

[Helmut]

X3 on cleaning the carb. Carb cleaning is a good first step.

 

[madhondalover]

the carb was not touched when the rings were put in only thing was i pulled the old piston rings off and put on new ones. sounds like the rev limiter is peging out when its only at half throttle. i will clean the carbs though. thank you everyone and any more info will help.

 

[TRX2fiveO]

When you set the cam in how did you install it and what did you adjust the valves to?

 

[Helmut]

the carb was not touched when the rings were put in only thing was i pulled the old piston rings off and put on new ones.

Did the ATV sit any length of time without it being started prior to you replacing the rings? If it did, there's a good chance the carb could need cleaning. If they sit long without starting, the gas will evaporate, leaving deposits behind that can stop up the carb.

 

[madhondalover]

the valves were left alone only checked to make shure they were at stock

 

[madhondalover]

is has a wisco piston kit in it when i bought it and my son went threw some water and burnt out the oil ring. the motor has been flushed when i put the new rings in. other than checking that everything else was at stock i dont understand what happend. would the silonoid couse this?

 

[Helmut]

would the silonoid couse this?

No, the starter solenoid wouldn't cause that.

 

[madhondalover]

i was wondering if a week spark would have something to do with it i have checked 3 plugs (new) and all the same spark so i did a contitnuaty ( how ever that is spelled) test and it has a weak pass through of elect. in the starter solinode. ok and i have gone threw all the conections and all are tight and good.

 

[Helmut]

i was wondering if a week spark would have something to do with it i have checked 3 plugs (new) and all the same spark so i did a contitnuaty ( how ever that is spelled) test and it has a weak pass through of elect. in the starter solinode. ok and i have gone threw all the conections and all are tight and good.

All the starter solenoid does is to send power from the battery to the starter, when the start button is pushed. It doesn't have anything to do with the spark and after the engine starts, it does nothing.

If you have a weak spark, it could be the ignition coil or stator. Did you have a good, bright blue spark at the sparkplug or was it weak? If it's red or orange colored, it's too weak.

 

[jgar]

When you put a big bore kit in do the valves get adjusted to stock spec.??

 

[madhondalover]

yes the valves were and are at stock spec/ timing and all are at stock.

 

[TRX2fiveO]

You may have a ring that is not spaced properly, when you installed the piston kit did you check the end gap on the rings before you put them onto the piston? Also when the cam was installed after the top end was rebuilt, the Lobes should have been facing downward and the 2 "-" marks allign with the top of the head. The valves are set at .004 int and exh. I'm not trying to belittle your mechanical abilities I'm just trying to get all the facts form the time you removed the old piston to the time you re installed everything.

 

[Helmut]

You may have a ring that is not spaced properly, when you installed the piston kit did you check the end gap on the rings before you put them onto the piston? Also when the cam was installed after the top end was rebuilt, the Lobes should have been facing downward and the 2 "-" marks allign with the top of the head. The valves are set at .004 int and exh. I'm not trying to belittle your mechanical abilities I'm just trying to get all the facts form the time you removed the old piston to the time you re installed everything.

I agree. I was going to ask the same question about the ring spacing.