i brought my bike as a non runner. all it need was a head gaskit. i got hold of one and put it on, but where it was left to sit, water and crap got in to the bottom end, i manged to sort that out and got the bike running. i went out on the field and it was running great for about 15mins when it started to spluttter and the it finaly stopped running. i havent had it running since!! tried cleaning the carb, as it had a lot of **** init. but when i kick it over its like its back firing through the carb and out the air filter. any idea's lads?? :ride:
i need help with 83/84 rm125
- Thread starter chunkus04
- Start date
Have you got spark?
Compression?
Fuel?
Reeds?
An engine needs air/fuel mix, adequate compression, and enough spark, all occurring at the correct time to ignite and burn the fuel mix.
From what you have given, there isn't anything decisive that points to what it is that is causing it. You need to check some of these things and report back to give more clues as to what is causing it and where you need to look to find the cause. Backfiring through the carb is normally a lean condition, but you don't really give enough information to ascertain what is causing your issues. Check some of those things, report back, and don't be afraid to update us with more information and ask more questions.
Compression?
Fuel?
Reeds?
An engine needs air/fuel mix, adequate compression, and enough spark, all occurring at the correct time to ignite and burn the fuel mix.
From what you have given, there isn't anything decisive that points to what it is that is causing it. You need to check some of these things and report back to give more clues as to what is causing it and where you need to look to find the cause. Backfiring through the carb is normally a lean condition, but you don't really give enough information to ascertain what is causing your issues. Check some of those things, report back, and don't be afraid to update us with more information and ask more questions.
- Thread starter
- #3
TimberPig said:
i know its got a good spark and loads of compresion. i also know the fuel is getting through to the carb and is the right mixture. my father in law has suggested i could have got some muck in the reed valve. how do i check and if needed clean them? do you know tyhe setting for the reed valve distance?? thanks for ur much needed help :bang:
rm_racer
Member
- Mar 15, 2005
- 501
- 0
Take off the carb, the rubber boot closest to the engine, then the reed cage should pull out. The reeds should not be chiped or cracked, and should be tight against the cage. I also suggest picking up a manual for your bike, their worth their weight in gold in many cases.
chunkus04 said:
Most manuals have a section called troubleshooting which will help you determine what is causing it. Check yours and it may help you.
Have you actually ascertained that the compression is good with a gauge, or is this just the it kicks over hard so compression must be good guess you are making? Bikes with weak compression can kick over hard if you have seized the piston and the dragging is causing it to kick over hard.
As you are finding out, working on bikes, or other mechanical objects, requires more than a manual telling you what is wrong. You have to be able to use your head and make observations to be able to determine why it isn't working as it should. No book can tell you what the problem is, and neither can we, only possible sources for the given problem. You have to be able to troubleshoot what the cause and solution to the problem is, based upon what it is or isn't doing.
Check the reeds, and get a compression tester and give us an actual gauge reading of the compression. Those two things right there will make a big difference in whether it will run or if more work is required. Also make sure your spark plug is good. If fouled, it could fire outside the cylinder of the bike, but under compression could fail to fire. Replace it if in doubt.
- Thread starter
- #8
of course i've read the troubleshooting section, and it says nothing about the problem im having. so without knowing anything about a motorbike engine, i thought i would try here to see what else i can do to find the problem not be partonised. thanks for you help but im not thick!!!TimberPig said:
I'm willing to bet that it actually does give the information you need in that manual, but you don't know what to look for. Your problem isn't going to be written out as you have here, because you likely have more than one problem and don't know what to look for. Thus far you have been given lots of suggestions, that you have not reported back on having checked. All you have done is come back with the attitude that your manual should tell you exactly what is wrong and how to fix it, and that we are being jerks because we are telling you that we can't tell you "replace this part and it will solve it" because there could be multiple causes. Start using your brain instead of your mouth and check out the things already suggested. There is no magical solution to your problem, only suggestions on possible causes. If you're not willing to make use of them, thats your problem. You are going to need to start doing some systematic troubleshooting to eliminate some parts from being the cause. Thus far you have cleaned the carb, but did you clean the tank? You haven't given a gauge reading of compression, or checked the reeds, or anything else besides saying it died and is backfiring out the carb. If you want help fine, but you have to be willing to help yourself by trying the suggestions you are given.
TimberPig pretty much summed up my thoughts, we can't give you a magical solution without you attempting some of the suggestions and reporting back. Since your not "thick" I'll assume you've done the absolute basic and replaced the sparkplug with a new one.
Chili said:
Thanks for the backing Chili, I hoped I wasn't the only one annoyed by his lack of attempting to make use of the suggestions. I figured I was going to get flamed for telling him to use what he's been given and go see if any of those are the problem.
- Thread starter
- #12
it has a brand new plug, the only things i havent checked yet because of the weather are the reeds and the compresion, i have spoken to one of my mates and he is sorting the tester out for me, i wasnt asking for a magical solution i was only asking what could be the problem! once i have found the problem then i can look at the solution. most of the suggetions have been checked while putting the bike back together so i know they are ok. like cleaning the tank as well as the carb, thats just common sence. by your replies im drawn to beleve that i need new reeds, but without checking i cant be sure. timberlog- wasnt ment to be funny but it just seemed like you were trying to talk down to me. so sorry and thanks for your help all of you.
chunkus04 said:
I wasn't trying to talk down to you and I'm sorry if it sounded that way, I was trying to tell you to get your butt back out to the bike and start checking those things and reporting back. We're not there, and since we can't observe the bike, you have to do it and report back in order for us to help you get this sorted out.
Also don't automatically assume that something you checked once isn't the problem, I've had times where I did that, and then finally checked it again, and it had loosened up or failed, and was the source of my problems.
I believe Chili is correct that the cylinder has to come off to actually access the reeds, but by pulling the carb out and looking in with a flashlight, you should be able to tell if they are intact and if the ends are chipped and cracked, and if they appear to be sealing. You can at least see enough to determine if they are definitely in need of replacement, although you cannot inspect them really well. Then once the cylinder is off, you start figuring I'll just toss in a piston and rings, as well as a fresh cylinder base gasket and it gets more costly. Get that compression test and take a peek through the carb boot at the reeds and start there. Report back with your findings and we'll go from there.
elcamino12sec
Member
- Jan 16, 2006
- 412
- 0
I had an 83 rm125, if I remember right you did not have to pull the cylinder to inspect the reeds. The 82 and later had the reeds in the case if I remember correctly. If its back firing through the carb it may be flooded. Install new plug, and kick. If you have a clean carb, good reeds and the right spark at the right time it should start. My rm125 never gave me a problem, it was a great bike. Just make sure you disassemble and lube all the swingarm and suspension parts. It has that full floater rocker arm thing that has allot of expensive needle bearings, seals and pivot bolts. Also check that your coolant is not leaking in the case. I had to replace the water pump impeller seal once. Other than that its a real solid bike.
I just checked the parts fiche and the reed block does come out of the cylinder on the 83 RM 125, so it is easy to pull it out and check the reeds. The 84 does indeed go back to the bolted to the reed block on the cylinder base style, that requires the cylinder be pulled to change or check them.
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- Thread starter
- #17
this was the case, but i had my father in law take a look and he said the reeds seem to be in good condition. but without taking the head off we cant be sure.just gotta remember where i put the rest of the gaskit set :think: while we was looking i noticed id left the fuel tap on thus having no petrol in the tank, so i thought i might have been a complete idiot and not had petrol in it when i thought it wasn't working!! so put it all back together and put more juice in it, warmed the sparkplug and tried to start it. but it just wasn't having it!TimberPig said:
crazyrydermx
Member
- Feb 4, 2006
- 72
- 0
Maybe he means he got a spark plug with a hotter heat range? Don't know by warmed the spark plug?
- Thread starter
- #22
sorry i havent replied, ive been working away all week, yeah i ment heated the plug up with a torch, and just in case the plug is naff im gonna get another one on tuesday when i get paid. if it still wont go it looks like im gonna strip down the whole engine and clean and change anything that need changing.
