stuntmonkee Posted May 17, 2011 Report Share Posted May 17, 2011 Good folk of PBMF please help me, for I am at my wits end... In April 2010 I bought a 2003 Honda Crf450 Supermoto. It was a non runner, due to a bit of the carb breaking and going through the intakes and taking the head, barrel and piston with it. Had I known what trouble the bike would be I wouldn't had bothered, but I wanted a SM, and at the time they seemed to be fetching a higher price than they are atm and it was in my price range. It also had a few trick bits on it such as a Wiseco Hi-comp piston, ASV levers, Talon wheels etc etc. To date its had the following: Summer 2010 Secondhand replacement head Standard Piston Barrel re-lined Secondhand carb Full gasket set New spark plug (good spark) Standard flywheel (had a weighted item with out the ignition timing mark) After all this, it ran twice...never off the kick start, I could kick away at it for hours and it wouldn't even fire. Its impossible to bump start. It only ran after I completely lost it a cut the bend off an allen key, stuck it in an electric drill and turned it over off the crankshaft. It wouldn't idle, but seemed to run ok aslong as I was blipping the throttle. Then the drill died...and I gave up and stuck it back in the shed. I started work on it again last month. and its now had - The head professionally refreshed with stainless inlet valves (the stock Ti valves give lots of probs), all the clearances set, stem seals etc. I just re-built the carb with a kit from the states - all the jets, needles, gaskets etc etc Top end gasket set Fresh fuel The carbs getting fuel, its sparking - but it still wont fire or run...so a few points- Pilot jet settings - 1 1/2 turns out. I presume I wind it in till it stops, then count the turns back out... Starting drill as from here, thoughts http://www.thumperfaq.com/starting_drill_02.htm What have I missed :eusa_wall: Link to comment Share on other sites More sharing options...
stuntmonkee Posted May 17, 2011 Author Report Share Posted May 17, 2011 Yes to all the above in pretty much every combination - jets are brand new, no shit in tank etc Link to comment Share on other sites More sharing options...
Hendo Posted May 17, 2011 Report Share Posted May 17, 2011 Cam Timing? Link to comment Share on other sites More sharing options...
stuntmonkee Posted May 17, 2011 Author Report Share Posted May 17, 2011 Cam Timing? Is spot on So, just clarifying now, is the engine flooding with fuel? or is it ok? I'm wondering, is there enough air getting in - air filter ok? No I don't think its flooding, but I'm not going out to check again tonight Link to comment Share on other sites More sharing options...
chancho196 Posted May 21, 2011 Report Share Posted May 21, 2011 Are you sure on cam timing? I know someone who had a similar issue with a CRF250 and put it back together 180 degrees out (he went by what he thought was correct). You have good compression? If I remember correctly, the stator gave up the ghost when it was stripped down too. Link to comment Share on other sites More sharing options...
millerich Posted May 21, 2011 Report Share Posted May 21, 2011 I had a pig of a Husky for a while that was a nightmare to start and never ran right until I forked out for a new stator. It would break down under load so despite there being a good spark if you tested it that wasn't the case when it was running. Given that CRFs are so common you might find someone to lend you various components for the ignition system to test sequentially. My money would be on a problem there. Link to comment Share on other sites More sharing options...
will#224 Posted May 21, 2011 Report Share Posted May 21, 2011 Go on seventeeninches, there are loads of guys who are experts with the crf Link to comment Share on other sites More sharing options...
kanerdog1x1 Posted May 21, 2011 Report Share Posted May 21, 2011 fuel tap off, carb drained, spark plug out and give it a good 20 kicks to clear out the combustion chamber etc... spark plug back in, fuel on, choke on, throttle closed(as in properly closed, with your hand holding the throttle tube forward) find tdc and tickle past it, and then a swift kick top to bottom(use the whole stroke of the kickstart, none of this girly half kick crap) and it should splutter, but probably not run. then choke off, throttle still very closed and another swift kick top to bottom and thats how you start the buggers. other than that, i might be 'broken' Link to comment Share on other sites More sharing options...
BudgetBoy Posted May 21, 2011 Report Share Posted May 21, 2011 To date its had the following: Summer 2010 Secondhand replacement head Standard Piston Barrel re-lined Secondhand carb Full gasket set New spark plug (good spark) Standard flywheel (had a weighted item with out the ignition timing mark) After all this, it ran twice...never off the kick start, I could kick away at it for hours and it wouldn't even fire. Its impossible to bump start. It only ran after I completely lost it a cut the bend off an allen key, stuck it in an electric drill and turned it over off the crankshaft. It wouldn't idle, but seemed to run ok aslong as I was blipping the throttle. Then the drill died...and I gave up and stuck it back in the shed. I started work on it again last month. and its now had - The head professionally refreshed with stainless inlet valves (the stock Ti valves give lots of probs), all the clearances set, stem seals etc. I just re-built the carb with a kit from the states - all the jets, needles, gaskets etc etc Top end gasket set Fresh fuel The carbs getting fuel, its sparking - but it still wont fire or run...so a few points- Pilot jet settings - 1 1/2 turns out. I presume I wind it in till it stops, then count the turns back out... Starting drill as from here, thoughts http://www.thumperfaq.com/starting_drill_02.htm What have I missed :eusa_wall: :eusa_wall: I would get a leakdown test done on the bike first mate.You could be losing compression through the engine by the sounds of it.You cannot even kick it over,this points to spark or compression,it wont idle either which could also be compression (or spark/carb's).(But you say you say new plug/good spark & carb's rebuilt so i ruled them out) It maybe all new but you only need a slight leak mate and it wont go,so worth checking it to rule it out. So based on you saying its getting fuel and the spark is good i will go with bad compression mate.Hence why you managed to start it with a drill and not manually. Link to comment Share on other sites More sharing options...
YZ faybo Posted May 22, 2011 Report Share Posted May 22, 2011 Hi I ran an 02 CRF450 motard race bike for years, earlier ones are the best! On these old slags one of the biggest starting issues that gets people is getting the piston to top dead centre on the first kick, not telling to suck eggs but also zero throttle as well other wise you could end up with sore feet and a flooded engine. When you did you carb rebuild was it with stock parts or DynoJet, reason I ask i had loads of issues with dyno jet shyte, ended up only using there needles and mains rest made it a f---r to get going. Also did you play with the hot start mechanisum on your rebuild? Last when you had the top end done did you do or a shop? getting the shims right for good valve sealing on these is important, and it is easy to have the cam one tooth out so causing issues (i should know). You mention you changed the gaskets, please say you used OEM honda, as after market are shyte, and can easily go even if torqued down, one cost me a new top end after it went at Anglsey in a race! The coils and leeds on these also go with time and espcially the plug caps Oh and ditch the heavier flywheel, idealy you want to machine yours down for faster spin up If you want PM me about these things Link to comment Share on other sites More sharing options...
stuntmonkee Posted May 23, 2011 Author Report Share Posted May 23, 2011 Ta Da... Excuse the shorts, I was rather hot from kicking the fucking thing. I believe my original problem was worn valves, which the shop sorted, and the recent troubles were carb based. I struggled to get a base setting, even going off the stock carb setup settings. I also cleaned all electrical connections with electrical cleaning solvent. The rattle is the kickstart on the exhaust, I need to check the return mechanism - its seems a bit loose on the spring back. Got to tweak the carb a bit more, change the oil and filter and helicoil the rocker cover bolts so I can tighten it enough to stop oil weeping out and running onto the header... Then its a new daylight MOT time EDIT - oh and Link to comment Share on other sites More sharing options...
El Gringo Posted May 23, 2011 Report Share Posted May 23, 2011 Good Man, perseverance and a bit of motivation Glad you got it running chap, worth the effort. The hunt for a motard for me continues! Cheers Chris Link to comment Share on other sites More sharing options...
stuntmonkee Posted May 23, 2011 Author Report Share Posted May 23, 2011 Good Man, perseverance and a bit of motivation Glad you got it running chap, worth the effort. The hunt for a motard for me continues! Cheers Chris Still get me some pics of the Z over though chris - I do same some loose change weighing my pockets down... Link to comment Share on other sites More sharing options...
El Gringo Posted May 23, 2011 Report Share Posted May 23, 2011 Will do chap, made a proper start on the wiring yesterday, i gave up at 4 oclock with a headache. Link to comment Share on other sites More sharing options...
YZ faybo Posted May 23, 2011 Report Share Posted May 23, 2011 Glad to hear your getting yours sorted, just a little tease but this is my baby with they can realy shuffle and handle with the right bits. Link to comment Share on other sites More sharing options...
stuntmonkee Posted May 23, 2011 Author Report Share Posted May 23, 2011 This it with its clothes on, about 15months ago Link to comment Share on other sites More sharing options...
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