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brettb34

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About brettb34

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    TT Member

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  • Location
    Colorado
  1. brettb34

    400 toasted need help and advice please

    looking at pistons 85mm is standard bore correct? many pistons are coming up "5.25 and 5.50 standard bore" since my cylinder appears to be in good shape should be able to do the 85mm 10:1 compression without bore work correct.... remember i have never cracked into an engine before, any alternate pistons suggestions.... thoughts on going larger? since i live at 8500ft. and ride mostly above10,000 i lose a bit of power compared to you guys in the low country! thanks again for any help or advice offered.... i also found a Weisco 85mm 11:1 for 135$... thinking about pulling the trigger on that one!
  2. brettb34

    400 toasted need help and advice please

    thanks for the advice and offering of help... i may need some for sure i have to figure something out... while taking it apart I never saw the little spring near the cam ! and have not found it yet... I've been huntingelk the last 4 days and season is over so i will look into "finding" the spring this week and investigate the bottom end a bit...
  3. brettb34

    400 toasted need help and advice please

    yeah upon looking closer after a good degreasing its obvious the the cam and rocker arms are toast when i changed the oils i found no metal shaving...perhaps too fine for me to see? any idea how to check oil pump while torn down? and what i would be looking at for bottom end damaged? seems fine metal shavings arent likely to create really obvious damage. or am i wrong? guess this will be a much bigger project for this winter! was hoping to not have a project this winter... and just ski and work! also not having the $ to do top and bottom engine... crazy ...frustrating that rushing an oil change and complacency killed my ride! take your time everyone.....
  4. 1998 xr400 bought 4 yrs agao in rough shape but still running strong with a valve clearence check oil change and some upgrades... so new in last 2yrs. mikuni pumper, new CR Hi bars, Q4 exhaust, tires, bark busters, front wheel etc. also fully plated in Colorado with all the new additions i cant bring myself to part it out. So after all these years.... while in a rush I did the fatal rookie mistake! oil filter in backwards!!!!! one long 3 hour ride and after that it was all i could do to start it in order to move the bike a couple blocks to my new place. never having torn into an engine i pulled it apart last night after trying to adjust the valves with hopes that i could do valves oil change and fire it up but... 3 valves were way looseand adjusted fineBUT the passenger side exhaust valve i couldnt get the feeler gauge under no matter how much i turned out the screw! to me... being un-knowledgeable about inside of engines i notice the cam looks rough...where it sits looks worn and some of the rocker arms look worn and 2 feel sharp on the edges (closest to spark plug)... piston allthough not removed yet looks ok but would like to replace since Im in that deep along with CRF450 cam chain... cylinder/sleeve looks ok to me? and not sure ...what am i looking at needing done given the limited view of pics and knowledge of my fatal mistake??? and if you know a reliable shop that can help me out for services in the Denver area????
  5. brettb34

    XR 400 help

    RE: Float...I will try to figure something out? Started up today 4th kick full stroke....idle raced the quickly leveled out to a nice idle then move t 1/2 choke and engine raced for a few seconds then came to a decent idle the run and the engine gasped and died! started back up on full choke, worked idle screw once warm to get decent idle at run position... hit throttle and engine raced and eventuall came down with some help from idle srew.... then turned the fuel screw in to about 1 turn out then 1/2 turn out until i noticed a difference! closed it completely and after a few seconds idle dropped to a sputter as if it were about to die? I will try to check the float/float valve soon... likely monday night or tuesday morning thanks for the help thus far
  6. brettb34

    XR 400 help

    removed and cleaned the throttle tube and lubed the push and pull cables as stated earlier and they seem to move freely.... feels like I'm missing something? I'm fixated on the carb... when I went richer everyone in TT said I was way too rich and they run the 50/150 3rd position! seems like I shouldnt have severe problems running same jets? I have the richer jets recorded in an older post labled XR not right? I will check them....
  7. brettb34

    XR 400 help

    nope have always avoided float height... dont really understand how to measure it? sounds simple but its not computing... what tool do i need to measure it? and would that efffect idle?
  8. brettb34

    XR 400 help

    havent driven it much since I bought it last fall because I had 2 other bikes and this was going to be a "fun" winter project... when i test rode it,,, it was hard to start but pulled strong ... cleaned carb and it started better...seemed to run lean so richened it up and then tt members said way too rich.. so went to tt members recommendations... also did the valves etc. as per tt members recomendations and now that everything done stated earlier and my idle is acting up BAD.. got some snow up here now so i cant and almost dont want to ride itlong enough to get a good plug reading... but before the valve adjustment and and rejet it was pretty fouled up... cleaned the New fouled up plug have put it back in and the short 2 mile ride around town and plug is pretty black but not nasty fouled.. going leaner seems logical but I'm at the lean side of recommendations... had 1 gal of gas in it over winter with stabilizer in it... tore carb out and it was still clean as a whistle... filled up with high octane for the ride hoping it could be the stabilized gas but no differences? and the decomp lever is not attatched.. never needed it anyway.. sold one bike have bites on the other and soon this will be my only bike:lame:
  9. brettb34

    XR 400 help

    1998 XR400 living at 8,500 ft 50/150 A16A Needle 3rd position from top uniair filter /Airbox opened/ aftermarket exhaust fuel screw 2 turns out cleaned thoroughly carb/linkages and lubed throttle cables valves adjusted properly no leak in air intakes choke plate appears to be in good working condition Problem: Bike starts about average to hard at full choke and idles smooth once it warms a bit move to 1/2 choke and bike races (idle fast) run position idles a bit then stalls and run position once warm will idle smooth with some idle adjustment, but when i hit throttle a little or a lot the idle races again and takes about 10-20 seconds to come down.... also when riding the fast idle disappears when gear engages and tires roll! when i come to a stop sign the engine races again!! (clutch pulled in) when tires roll engines runs pretty good! i found that in 2nd and 3rd sometime i will feel the engine race almost like a stuck throttle???? any help would be greatly appreciated! thank you
  10. brettb34

    XR4 not right??? help or ideas

    come to think of it the engine may not have been cold when i did it also.. I read somewhere that it needs to be cold..pretty much not ridden? is that true? I had been working on the jetting also that same day... what is the straw technique i've read here? i see how you put the straw in the plug hole and watch go up and down but when according to the straw is TDC on Compression? hope its just valves... seems likely for it now that I realise I adjusted valves when warm and it started easy and when cold now it just wont crank over for me
  11. brettb34

    XR4 not right??? help or ideas

    Been real busy but now looking back into my project xr400... Since adjusting the valves I cant seem to start it??? it was on the compression stroke (slight wiggle valves) does not seem to have compression? decomp lever was removed prior to me buying it.. cable still attatched... could something be wrong with it? would a stage 1 cam remove that decomp all together?
  12. brettb34

    no rearend rebound on xr400

    I have a shop manual and fixed the front fork issuue and tried adjusting the rear shock in both directions (S/H) both compression and rebound set back to "standard" how much to get it serviced.... I would work on it myself but whats the deal with the Nitrogen??? I wouldnt really know where to start
  13. brettb34

    XR4 not right??? help or ideas

    when I purchased the bike one month ago .. I tore down the carb and cleaned everything except the air cut offf chamber??? checked boots prior to test run looked good and solid .....and I started with 50/150 middle position and 2 turns out rode it again last night to try and get a better description of what I'm experiencing and also realised that I max out each gear pretty quickly up to 3rd/4th... didnt get out of 3rd much... a noticible micro hesitation during wide open throttle in middle of 2nd gear any other tests I could do? was thinking about timing and compression?
  14. brettb34

    XR4 not right??? help or ideas

    i rejetted to 50 /150 per tt recomendation and had alot of decel popping and irradic idle and tough starting too! went to 60 150 and most mid range smoothed out and bottom end bog mostly gone? went to the 162 main and mid range got better!! thats why i'm so confused?
  15. 98 XR4 California bike now in Colorado at 8500 ft smog junk removed opened up air box uni air filter fmf megamax exhaust (came on the bike) jetted to 60/162/middle position stock needle 3 turns out on fuel screw Finally got it running decent...then checked valves... exhaust valves were loose...intake valves fine checked stator everything seemed good... pulled exhaust everything clear no apparent air leaks problem is difficult starting and just doesnt run smooth like mid range miss or something....its hard to explain feels like it could be fuel but plug looks god once warm it starts 1st kick any advice or if your in CO and want to test ride I'm open to that too
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