Big end gone honda fes 125

[Paulf]

I got my bike running top end good, however when ticking over I have good a knock most likely big end as gone as well. I managed to get a honda workshop manual so I have a clue. But splitting the crank case seem to require a splitter, looking on eBay they are around 200 quid. Do I really need a splitter or is there another way. Thanks in advance Paul

[neptune8]

I will try to help, because no one else has volunteered yet. Before you split the cases, strip down the engine top end, thatis. head and barrel. You can check the big end by putting the crank at top dead center, and trying to move the connecting rod up and down. There should be no play or movement. Also check little end for play. It is possible to split cases without a puller. Remove all bolts, and try to tap the cases apart with a rubber mallet. A home made slide hammer could work . Do not insert wedges or screwdrivers into the joint. If all else fails, take the engine bottom end to a motorcycle workshop, and ask for a quote to split it. With the right tools, it would cost half an hours labour. Hope this helps.
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Enjoy yourself, its later than you think

[Paulf]

Thanks I will do as you suggest the manual will help to strip the engine ready for the split.

[cazmac1]

Good advice here, I too recommend stripping the top end down first and checking for play, where the noise is coming from can be very deceptive.
I done my top end with the engine still in the bike even though the manual says it must be dropped. Good luck.

[Paulf]

Big end bearing has gone and with the amount of free play 1/4 to 1/2 inch it has really gone. Engine is out head,barrel, piston and right hand crankcase cover off along with flywheel nut. Ran out of time and got to get flywheel puller. A new crankshaft is £120 of ebay hopefully split case and fit a new one. Keep you posted I bought very cheap and the ex polish owner said it was inactive now I know what inactive means.

[stevo as b4]

It will of ran out of oil or had a bad leak, or 3rd most likely reason is it's never had an oil change. These bikes are too new and generally don't clock up enough miles to wear an engine out.

My mate ran a main bearing at 38'000 miles on a CG125, I reckon it was missed oil changes or letting the level drop a tad low before long motorway rides that did it. Otherwise it would have sailed to over 50'000miles IMO, and a CG has to be an older and crapper engine design with its OHV design etc.

[Paulf]

Oil change likely culprit the drain must been gunned on I had to use nut extractor and breaker bar I thought for sure the sump would crack. And oil was getting black must have been bearing.

[Paulf]

Case split, thanks for suggestion to try with a rubber mallet it worked! Crankshaft out signs of overheating and no balls or rollers, they are metal flakes in the sump. Well what to do next have the crankshaft refurbished or new complete with bearings. Anyone gone the route of refurbishment is it a cheaper alternative or I could follow the Thai guy on YouTube ....joking!! I tempted to get a dubious (not oem) crankshaft assembly for £120. Thanks in advance Paul.

[Robby]

How much is a used engine?

If the crank is fucked, the cam probably isn't far behind it.

[iansoady]

As said, a used engine is probably your best option if you can find one.

By the time you've bought all the spares, gaskets etc you need you'll probably spend more than the bike's worth.

https://www.ebay.co.uk/itm/Honda-FES-125-Pantheon-year-2000-Engine-/272534763487?hash=item3f745677df:g:8ToAAMXQNo5TYkWo
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Ian
1986 Honda XBR500
1952 Norton ES2

[neptune8]

IMO, a substitute engine is not always the best option, as it is a gamble. Unless you have ridden it, you have no idea what it is like inside. Also, unless you find one of the exact year, you will have problems, for example, the exhaust might be different. At least if you rebuild your engine, and do it right, and runit in carefully, you will have a long term investment. You will also have cause to be proud of your work.
____________________
Enjoy yourself, its later than you think

[cb1rocket]

What year is this bike? Currently rebuilding one myself now. A 2008 bike. The fuel injection 4 stroke.
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Honda H100S2 Rebuild - https://www.bikechatforums.com/viewtopic.php?t=253852

[stevo as b4]

I used to think your way, but let's be honest here if you want the bike to ride and do a job as opposed to being a pampered garage Queen, then a used motor is always cheaper than a full engine re-build on a modern four stroke.

And also being honest, what are the chances of every second hand used engine being fucked like the one you already have, I'd say very slim based on my 2experience's with fitting used engine's to bikes.

Of course if you were talking two stroke engines, then all of the above does not apply, but saying that it's still a good idea to have a spare, crank/bottom end/cylinder etc sat around for re-conditioning and spares, as well worn two stroke's can often go pop without much obvious warning.

[Robby]

I always imagine Stevo sat in a large chair made entirely of spare KMX parts.

On topic, I'm suggesting a used engine because I wouldn't bother with the existing one, and I rebuild engines for fun. If the oil is full of metal shavings, then the engine is too. This means that during the rebuild you have to assume that everything is fucked, and spend an awful lot of time stripping, cleaning, inspecting and measuring many things - then replacing a load of them.

An engine is made of a large number of fairly cheap components. A rebuild after this sort of damage will easily cost £300 in parts, although I wouldn't be surprised to spend £500.

[Paulf]

I have a 2005 fes I brought the crankshaft off maxmotorcycles for £115 and a gasket set for £28. Been rebuilding today got the crankshaft in and built up to fitting oil pump, starting gears, stator flywheel, and crankcase cover. Run out of time. I did look at 2nd engine one off ebay had broken cylinder head cover bolt, a mangled drive for the water pump etc and that's what I could see off the photos and £100 price tag. A tip when building up to pull the crankshaft bearing though the drive cover, left when riding, use the inverted stator flywheel and starter ring assembly with washers and pull using tightening the nut, it worked for me. I found out in desperation not having a puller.

[Paulf]

Engine back together and back in frame, all connected up. Ran without spark plug in to get the new oil circulating. It had a complete strip down and new barrel set £58 plus the new crankshaft and gaskets. Replaced spark plug and fired up on second hit of the button. Had a slight leak on thermostat assembly stopped and re bed the seal and start and ran until rad fan kicked in. Ran like a sewing machine and no further hassles. I know some people will think what a waste. Call it a senior moment I am 60 plus and the joy for me was stripping an engine and getting it running. I did many times to 2 strokes when I was a teenager they were a bit easier. Now to sort out the other problems possible oil seal leak on forks and sticking rear disc plus other minor niggles.

[Stalk]

Yes, it may have cost you a few pounds, but there is nothing quite like the feeling of success! Well done chap!

[cb1rocket]

Hi Paul, what puller did you use to take the stator flywheel off?

I also got a crank from maxhonda too

here is mine in bits!

https://lh3.googleusercontent.com/ZIj5B-WBK3__HNlWHS8csROzZ4zzMUGX8SSaXcHFZB4r16KDDJCDLZik5oNYbyX_zhIfSIwPM826CSIWRfi0Shgxr7mVdSTV3Dek22YGR7AtMODLNFzt4ZVh7bFqj8iLUUtDMCK7S9iFpPcixpaFzozG55sU4raL9PYi6wLEhptF2sdF5tHahs7p5SK1dG5C9-ajzt5uewN445UotomXQfYfRWNKS8n702YlVVIbhWytgsI2rF_or2aoSQusmRNT4IamXnHfriZ3U7G4Htp_l5g7HxObb3ctIhyKvcUaNu22V_UjVWrz2vwoW-pSsh2pBs2D59jJqgNZtHofoy4q5XQx6hXznue5wBkLnS5PykMCfg3dHJ16qCdq-Qh8M2Jy2HKOhF2Dsk3Z3xYsbcY3PPz8AdvGzxsO4YIw1bBL_nVZU8C4HNKzDbioAeRLJ8ibpPkdnxcpINsnJR3K3JfNI_lA1AC4fUmE1aP0rqCXgLvNY71VHQScB-SoHpoXcLq6ipbUf92YJEaOHXZsiFwueMYImpUhwp7P52Qv00GcnDSw35fK8kRKLV8Wv0NAhAFf-oTTu6G3M94xImwMxXg2ZYhiF1xKjsLE8B7dRsSCHHow-gmH=w852-h639-no


https://lh3.googleusercontent.com/SuW2xIu2VoC4b4kKbxxRFF77B5wkuoFzxcUI84ffURNMM3IAEjNv2nYTClvQ1htZG5x4V69PRHFJbbL2ar3YDt5tlyq9sEREBb3ESxJxWrJK_5XP8eZt50uym-bl9g6V3pkmZZGHN_5-FS3aWk_LgoPi4xW_c1J_0Jwz7n4vlknxAk3MsYWSy30aIsYfskREl3liw3RB-8gkCD1w-qvI_u1rw5cLOVAwEjia1KzTVkM5X1289ID8vobiJMlMBn4RYkTx4ToIS5c6BYzmrsrv_KkNFpNnl4SoNXXgIA8QAZMPumoHpRYSixtJMGgPxruCGscLtaVcYzyrt00OdWl2IKjIPhl_1hxKMUQBPhgqycxdBNPTV9d_FcrGGCIZR4nl3Vrj6gA9Hp2i1MQnRcYpMiqWnOrcTrzBooWnqTGiIFuuR-j8WODqOj3dGK9EfCs0ac4Sl4kbWCTa0Zzx3ElQvWwe0Dqjhh1WXfZcXPX15clHD6o3BoASPYYFYFEISnT93JlD5c4vcJHEzYK1MYtkgjtBuyNxZCOrD4VggW_I_ScIpDqM1_ex05I0bW06rvxp5OHd5nC1LoA9oamnY0gj2oKsrJqq4_LmDt5t97WRbE51q--Lxz2s=w479-h639-no



and a video of buggered big end

https://goo.gl/photos/CZdC3JCtmDzxxwyeA[img]
____________________
Honda H100S2 Rebuild - https://www.bikechatforums.com/viewtopic.php?t=253852

[Paulf]

I used a 3 leg puller from amazon, a set of three for £10. The largest one is the one to use. But because the bottom edge of the stator is radiused to stop the legs from sliding off I used the cable ties to form a ring round the bottom edge of the puller. Make sure the cable ties are tight. Then slowly turn the extractor screw. The stator is then pulled off. It goes with a bang. Leave the stator but on loose to centralise the screw and to stop it flying off. Once the stator is off there are three bolts to undo take the oil pump out. And the starter gear. I then used rubber mallet on the left protruding shaft of the crankshaft, the left whilst riding. It only took 1-2 blows to get it to separate. Then knock the right crankshaft out. Be prepared for some oil. Then clean the crankcase halves out there will be the remains of the bearings, I used a strong magnet. Pull the cankshaft on see above using the stator. The seal knock out using a big socket I found a 32 mm was OK. It needs tapping out. If you need any help give a message and I will answer mostly after 6pm.

[Paulf]

Stator but on to centralise the puller. And cable ties in a circle at the bottom of the legs to stop them splaying. Sorry on phone.

[Paulf]

Stator nut dam predictive text

[cb1rocket]

Cheers Paul
____________________
Honda H100S2 Rebuild - https://www.bikechatforums.com/viewtopic.php?t=253852

[cb1rocket]

so I didnt have much luck with a 3 legged puller so i opted for the real thing!

Progress to follow!

https://lh3.googleusercontent.com/WlTso2dAJ51ocfGKmh-cgkwmhusbemoIuZBqn3-xWIvSAOwSaMqMuI1VJVA8a-w6EkIrWfPI5C8PgQGfPvBI4kAd12YtBB3WYq0kkB14qyUsMlNYPFt4PPe7UKG4E_y3KBhW_Tvom7o8V_LItT464lto8ja-zG8K6Fwu9HgmbbqWOHe3Ji5mhXNKSOLRB_WtL69KAeviT5OaPd4ol3hFIJvBD_JCFa3fJsv9HlXxS5lybG85LIe6HqfDp-_gOz3ghcBkvwqYmY5La5ejPFJ4TMrNQGyySr_GUFqZA6TmM6tngCt0udBtvkzfVrl3KwskoeT9CYGMw3ARI0ImI_tSiys1mesRLyZ8m8r38eT5Sh0il-b8atH6DKhNRj54SPDvNd2h-sGH7Mx3tosBnNFK9Ssu2ajqRVpZZrnxR3Sq-t23csdzDxT77F9akO3m6ftllVoQM9ZcVr8tuf272fhZ6JD093aZ5tMbPWL4E6MvubPY4swR15xHyNF0rVHzSZ146qghYdSFouth3jiHiMqDtYr8glYErGlMXrsWVgnamr0tT1mX3-8Pp-lchdlsajSuVTyacoBTPgCwiL-SHfgFlmLf6r2_1FHvMAJ0i-SC2uExd_2rRwvq=w443-h589-no
____________________
Honda H100S2 Rebuild - https://www.bikechatforums.com/viewtopic.php?t=253852

[Paulf]

Well it should be easier good luck.