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View Full Version : Trouble with sputtering on top end


DareDevilQracer
10-09-2007, 07:14 PM
Ive got an 86 R with a newer motor in it, not sure what year though. Ive got a 310 Pro X cylinder, dynoport pipe, Delta V force reed cage w/ carbon fiber reeds, and 38mm airstryker carb. Ever since I bought the bike it has been sputtering on top end. It is especially noticable when coming out of corners and trying to get up to speed for jumps in 2nd and 3rd gear. IT will pull hard up until the very top where it sputters like crazy. I tried jetting the carb on it and it never got better. I switched to another 38mm airstryker and tried all kinds of jetting in it and still no luck, although it runs best with a 170 main. I have inspected the reeds, they are fine. I have no leaks anywhere in the intake. My plug is properly gapped, and my airfilter is clean. This week I am rpelacing the right side crank seal in case the top end was sucking oil. Im going to put ti abck together this week and ride it, but if that doesn't fix it, does anyone else have any ideas? I have not checked compression but the bike starts second kick every time.
redrooster310r
10-09-2007, 07:21 PM
open air box lid? k+n w/ out ware for dry .. foam for wet but def open the box . top off.
RedRider23
10-09-2007, 07:29 PM
I've had the same problem before. i already had my lid off my airbox. but i didnt realize that i just had a junky k-n air filter on. changed my filter and ran awesome.
redrooster310r
10-09-2007, 07:31 PM
Originally posted by RedRider23
I've had the same problem before. i already had my lid off my airbox. but i didnt realize that i just had a junky k-n air filter on. changed my filter and ran awesome. yeah. what he said. ... a choked up filter will do that
Rollscanardly
10-09-2007, 07:38 PM
If you are already changing the right oil seal cause its leaking it would probably be a good idea to change the left seal also...if it leaks its game over...Just my opinion though and im no expert by any means.

Hunter
atvmxr
10-09-2007, 07:54 PM
Id try trouble shooting the electrical before you tear it all apart. my was doing that and a stator swap fixed it.

and try a new filter...
DareDevilQracer
10-09-2007, 08:47 PM
Im running a k&n filter w/ outwear and no airbox lid. The filter is in good shape, guess I could try a UNI though.

Rollscanardly, I dont know if the right seal was leaking, just running out of things to try.
Aceman
10-09-2007, 11:02 PM
Have you tried narrowing the plug gap to .020?

It doesn't sound like a filter problem though.
my88r
10-09-2007, 11:09 PM
Originally posted by DareDevilQracer
Ive got an 86 R with a newer motor in it, not sure what year though. Ive got a 310 Pro X cylinder, dynoport pipe, Delta V force reed cage w/ carbon fiber reeds, and 38mm airstryker carb. Ever since I bought the bike it has been sputtering on top end. It is especially noticable when coming out of corners and trying to get up to speed for jumps in 2nd and 3rd gear. IT will pull hard up until the very top where it sputters like crazy. I tried jetting the carb on it and it never got better. I switched to another 38mm airstryker and tried all kinds of jetting in it and still no luck, although it runs best with a 170 main. I have inspected the reeds, they are fine. I have no leaks anywhere in the intake. My plug is properly gapped, and my airfilter is clean. This week I am rpelacing the right side crank seal in case the top end was sucking oil. Im going to put ti abck together this week and ride it, but if that doesn't fix it, does anyone else have any ideas? I have not checked compression but the bike starts second kick every time.

make sure you have proper slack in your throttle cable. i had my to tight and it was holding the slide up giving me the same problem as you.something to check out:macho
DareDevilQracer
10-10-2007, 04:40 AM
Originally posted by Aceman
Have you tried narrowing the plug gap to .020?

It doesn't sound like a filter problem though.

Yes the plug is properly gapped.


Throttle cable is fine too.
86250rrider
10-10-2007, 06:05 PM
Originally posted by DareDevilQracer
Yes the plug is properly gapped.


Throttle cable is fine too.




he didnt say to gap properly...he said set to .020. stock is like .035 or so. i makes a huge difference on mine! try it ,its free:rolleyes:
my88r
10-10-2007, 07:09 PM
Originally posted by 86250rrider
he didnt say to gap properly...he said set to .020. stock is like .035 or so. i makes a huge difference on mine! try it ,its free:rolleyes:
did you get those pms i sent you:cuss:
DareDevilQracer
10-10-2007, 09:43 PM
Plug is gapped at .020, new crank seal is installed and I replaced the ignition ground and added an extra ground somewhere else just in case. I wont get to ride it until Saturday, when I do I will let ya'll know how it runs. I appreciate the input!
DareDevilQracer
10-12-2007, 03:05 PM
Well its fixed and running 100% now after I jetting it again. I replaced the k&n filter with a UNI, replaced crank seal, added extra ground wires, gapped plug even smaller and leaned out my gas/oil mixture to about 35:1. One of those things (or a combo) did the trick.