The old parts bike was a 3LN3 an had a blue switch block. Taillight is the same as both cherry and parts bike. Headlight says 3ln3. There are single and double projectors for 3LN3 onwards. Pretty sure it's a 3. But parts have been changed over in these bikes lives at some point.
The frame has 3LN 282*** which makes it a 3LN3. The compliance plate doesn't give much info, just "1991 FZR250". So I took her for a much longer (flat!) run today around the block and I'm noticing a few things now that weren't apparent before. When riding at low RPM she almost feels like she is dropping cylinders out. Probably starting to hit the gunk. I did fill her up with premium fresh fuel so that's not the issue. At the higher revs she seems to do fine, the more I ride the less problems I am seeing but still enough to suggest to me the carbies need a look at and clean. To be expected though, it had been sitting for a while. The throttle definitely needs new cables as the lack of any spring makes it a bit annoying for someone as pedantic as me. She sounds a bit "ticky" to me at idle the more I listen,but hard with nothing to compare to. Perhaps the valve clearances need doing too (a pain, but doable none the less). For the most part everything else seems pretty good
] what info are you after exactly? dimensions or some kind of serial number on the rear sprocket? I'll look at the front sprocket later. The only marking I can see is "56" (assuming number of teeth).
If u remove your front sprocket I would like to know if it has a 7mm or 9mm thick sprocket and if theres any spacers used etc. The output shaft increased in length from the 3LN1 to the 3LN3 and later models. The story is very longed winded and discussed + a few pics on grasshoppers thread
It may be a case of flooding at the lower revs, but yes, carbs are almost definitely going to need a re-do. I have the same tick on mine. I think a thinner oil may be required, and the valves adjusted. I wondered if its the cam chain that may have an issue too. Grey, I have a number of sprockets from a 3ln1, and the old one from mine, and also the parts bike (both 3ln3) do you want me to dig them out and have a measure and let you know the findings? I put the sprocket I got from slipstream went straight on....
get some 3bond engine conditioner and go nuts on those carbs you have @GreyImport who knows fizzer carbs better then the back of his hand i'd recommend to change all your fluids and sparkplugs and filters, then see if its still ticky on idle before delving into valve clearances. For peace of mind atleast
Mate ...that would be great ...... its still really an unsolved mystery ...... the only reason the 3LN3 here is a goer is I used a spacer on the front ...... far from perfect in my opinion.
@GreyImport Ok when I get to the front sprocket I'll let you know. @Th3_Huntsman Thanks for the tip, I'll start digging deeper over the weekend.
Heres a rundown on checking the cam chain/cam chain tensioner http://2fiftycc.com/index.php?threads/my-fizzer.872/page-4#post-7827
@GreyImport any tips for removing the front sprocket cover? cant' seem to get the dang thing off, have removed all the bolts though.
Assuming, youve taken off the gear shifter linkage..... Grab a mallet and give 'er a couple of meaty whacks. Dont smash it, just loosen up the dirt, grime and oil that combine to become a glue to hold parts like this on. Then, grab a screw driver, and give a few light twists on the edges against the frame to get a bit of lateral breaking force on it. Should pop it.
Awesome cheers. By the way, how is the sump plug threaded? it seems to have a screw in it I can't turn and I don't want to force the main plug if I'm supposed to undo one then the other....? I don't think these things have been looked at in a while heh The more I dig the more I think this bike was made for lefthanded people. oil filter is very difficult to grip with my right hand lol so much fun.
Oil filter will be stuck drive a flat blade through it and undo that way when putting new one on but of oil on oring will make it easy to take off with filter wrench
Done that before LOL. Left hand thread for the oil filter the sump plug SHOULD be standard but im open to suggestion fro ma bloke thats worked on one @Grasshopper @GreyImport
Well, an afternoon of digging has been mostly eventful. - The exhaust header has obviously seen better days. Any tips on how to restore these? can you simply run them back with a wire brush, prime and paint with some sort of heat resistant paint? No holes though, but with the amount of rust I'm going to do something about it. - The coolant was quite nasty, brown and a bit lumpy. Took the radiator off and gave her a quick flush through with the hose and I think she'll be right. Water came out clear pretty quickly and can't see any evidence of rust flakes etc. - Fairings in very good condition actually, I was a bit surprised. Only a couple of small cracks at the base where they join that I may strengthen the inside with a bit of fibreglass to prevent them growing. - Pretty clean and tidy throughout, few places that need a wipe down and a clean up but for the most part is looking pretty good. - opened up one of the carby bowls to see what was going on, they look like they have been overhauled before as they are very clean and had some sort of gasket goo on them. I ordered a Litetek kit (thanks to @maelstrom) and I'm toying with not actually doing much. I may use the Litetek on the bowls and save the others for later (the old adage if it aint broke don't fix it). I guess there's positives and negatives, worst that can happen is I put her back together to find I have to pull her apart and do them anyway I guess. If not she may go for a bit longer... who knows. - Spark plugs are rusted and carboned up, probably driving the performance issues I was having. New ones are a goer I reckon, if that doesn't drastically improve things I may need to take a closer look at the carby. - Got the damn front sprocket cover off, don't know if the photos are helpful @GreyImport but that was the best I could do without taking the thing off. She's pretty pointy and gunky though so I'm doubtful its ever been looked at and probably needs replacing. Don't know how to get the sump plug off though, it seems to have a philips screw in the centre then on the outside somewhere for a socket. Either way I can't seem to budge it even with a couple of mallet taps so that's gonna hold me up doing the oil change... Any advice from others? Which way is it threaded? do I even need to touch the screw - can I just undo with a socket?
Not too many gremlins! - The sump plug should be right hand and a socket should be fine to remove it. the phillips head thing is to undo faster when cracked i believe. (you read Japanese check that manual) - for the header a wire brush is sufficient or if available a gurney and compressed air after. Don't worry about primer just get VHT high temp header paint. Do not buy brake paint even though the temps should be high enough it melts away. - Those plugs indicate it is running rich but that may be because they are well and truly shagged. - That front sprocket is horrid please replace ASAP. New chain and rear sprocket at the same time Get a red o ring chain - i don't like the look of those flakes from the gasket goo some of that may have went through and blocked the jets (worst case and probably not necessary but not worth the risk). Good stuff on getting the LiteTek kit have some proper gaskets, I would clean your jets and passages again just in case, you wont need to split the bank and it cant do any harm.
