Gen 1 - low compression - build questions

[rubbersidedown]

Sounds like maybe it had a fueling issue,
Rubb.

 

[JaiHutcherson]

Man I’ve been saying that for two months. Mechanic that did the lower end replacement/undercut said no. Then I continued and work with a guy that did some of the other mods and he said no. I’ve checked tank it’s like new inside. I’ve ran seafoam green through no change. When I get my cylinder and head back I’m going to change fuel pump/filter assembly just to make sure I’ve taken care. Someone tonight said something about a TPS. I’ve had family here today so I’m getting ready to dive in the manual and see what where how why of that.
Thanks

 

[202mphbusa]

So compression did not go up with oil in plug holes
compression is on the low side
Valves look like poop.
simple
pull the head. disassemble. clean the poop out of everything. Lap the valves. fresh valve seals
reassemble with fresh gaskets AND crush washers to fix your leaks
presto She will be good as new

 

[JaiHutcherson]

So compression did not go up with oil in plug holes
compression is on the low side
Valves look like poop.
simple
pull the head. disassemble. clean the poop out of everything. Lap the valves. fresh valve seals
reassemble with fresh gaskets AND crush washers to fix your leaks
presto She will be good as new

Thank you 202mphbusa!

update:
I have pulled motor, head, cylinder and taken to a great machine shop. It’s nice living in DFW where we have everything!!! I was surprised at how easy it was to get it all out, labeled, and prepped to get everything back from shop and assemble back together. It was my first time breaking my bike down.

guy at the shop was super cool. Took the time to go over all the components I took him; head, cams, pistons w/rings still in place, and cylinder. He basically showed me what my leak down test revealed. #3 and #4 cylinders running cooler than the rest per coloration of head and valves. Looking at those pistons he showed me discoloration past the 3rd ring (told me that should never be unless bad rings). Also looked at #1 and #2 on head and was able to show me where oil was leaking past.... valve stem seals. It was pretty cool getting to see what I heard in leakdown and be able to put it all together now. Much better understanding. Obviously all you guys right on the money.

got rings yesterday. Hoping the valve stem seals come today so I can take up to the shop. Said he would have it all back to me In a cpl days. They are about 3 weeks out but since I’m a DFW guy and this is my only mode of transportation he hooked me up. He is doing a full head job; CNC port and polish, etc. the cylinder was in great shape only needs minor honing, and pistons in hood shape except all the trash that came in from valves via air box. Reading comments here and talking to folks I decided to keep stock pistons and bore. I am putting the money in head work now. After Christmas I’ll get new cams that adjustable. That’s a whole new world I need to study for. I need a bike that’s got torque and quickness not top speed. I also need a bike that can stand in Texas traffic in 108 degrees and not melt.

thanks to all for the help and guidance. I seriously could not have done what I’ve done without y’all and this site. Here are the final out pics and I’ll post more of the rebuild...... oh gawd I have to remember where all this crap goes!

jai

 

[JaiHutcherson]

Update:
Listen to most of y’all and stuck with the stock pistons/rings. Went with a cnc ported and polished valve job and new cams. Hopefully soon (6months) I’ll be able to go with a big bore. The machine shop was great. Showed me the issues where things went wrong why and how. Looks to be too hot an ecu flash was burning things up on two cylinders. So hopefully all hood and I’ll be able to put it all back together now that i been a few weeks. Lol seriously.

 

[busakiller]

If your worried about over heating I wouldn’t go big bore unless you do the dual fan mode.

 

[JaiHutcherson]

If your worried about over heating I wouldn’t go big bore unless you do the dual fan mode.

Thanks! I did the dual fan mod last year. I live in Texas and was commuting 45 min in killer traffic all summer. Was t really over heating, but the heat coming up was over heating me. Lol

 

[Dopey]

Update:
Listen to most of y’all and stuck with the stock pistons/rings. Went with a cnc ported and polished valve job and new cams. Hopefully soon (6months) I’ll be able to go with a big bore. The machine shop was great. Showed me the issues where things went wrong why and how. Looks to be too hot an ecu flash was burning things up on two cylinders. So hopefully all hood and I’ll be able to put it all back together now that i been a few weeks. Lol seriously.

Out of curiosity where did you get your flash done? If you don't wanna put names out there I understand but was just curious if it was just a basic flash or if you had it tuned in a dyno thru the ecu.