CR125 '98: Any other year's have interchangability with the crank cases?

So pretty much the old left crank case had the case saver broken off, and the right crankcase had a stripped thread (where the long bolt for the case saver goes). Anyway, the bike came with a another set of cases which I presumed were for the bike but were not. No idea what year they are, but the original cases have a bit missing around the bearing on the input shaft on the right crankcase, whereas this older case does not (it just has a raised ring around the bearing), thus unless I get it machined it won't really work since the output transmission shaft gets squashed between the cases due to this raised bit.

 

So, I bought a new right crankcase but the seller sent me a case that was repaired with JB Weld (yep, they thought that was OK) so it's unsuable. Anyway, I can't find any '98 cases for a decent price at the moment so I was wondering if cases (from '98 onwards) would be alright to use? From my understanding, the '99 bike is pretty much identical in the bottom end. Any other years maybe? From my memory, the only differences for the 125s were the cylinders.

Edited by KICKERMAN360

As far as i know you could pretty much use any case from 90-99 and it would fit. Only 98/99 have slightly wider transfer ports but you could also adapt older cases to make them fit. Just put a 98/99 base gasket on them and you'll see the overlap.

 

Other than that there is no difference! Basically cases from 90-99 are all equal except for the mentioned transfer port width.

 

Check the picture below where i put a 98/99 base gasket on a 90-97 case:

15457360785_75ef3ff973_c.jpg

 

Here i matched a old '90 Mugen (with narrower ports) to the wider 98/99 cases. Again-check the overlap by putting the 98/99 base gasket on the old cylinder:

8524512880_83692a2d02_c.jpg

 

after some minor dremelling:

8523401987_c37791e79c_c.jpg

Thanks for the information! I looked at getting other cases but decided I'm just gonna mill the bit around the bearing to allow the gear to rotate. I have access to a drill press that was formally used for milling so it should be fairly easy. Otherwise I might look at using the old case since I just need to repair a stripped thread in

Wait so your tell me that all the cases 90-99 are pretty much the same even though the 98 went to a whole new frame? So mounting points are all identical?

Wait so your tell me that all the cases 90-99 are pretty much the same even though the 98 went to a whole new frame? So mounting points are all identical?

Correct!

That said even cases from 2007 would fit! The only thing that changed is the bolt diameter. From 1999 -2007 they have upped the diameter by about 1mm when compared to 1990-1998. They went from 8 to 9mm engine bolt diameter.

How bout the later years clutch? Will they fit Pre 2000 motors?

How bout the later years clutch? Will they fit Pre 2000 motors?

no-since they use 1 set of discs more they ae wider and won't fit. Unless you change some things like the cover and hub etc...

 

BUT why would you want the new clutch anyway? The old one never had any issues, was long lasting and lightweight...no need for an additional set of discs and all the added weight that comes with it! That was the major drawback of the later models anyway: too much weight and resistance in that tranny. All gears are way too fat and heavy. Too much power is lost just inside the transmission!

 

Want and example?

 

Waterpump gear of latest models (111,2 grams)

15514050426_18e431c57a.jpg

 

Same gear of earlier years ('90-'96)--------> HALF the weight !!!!

15535062291_44b24c1923.jpg

 

When i ordered that gear for one of my engines i got the new and heavy part instead as it replaces the other one. Just holding it in my hands told me it was too heavy compared to the worn part. So i set out to find one of the original parts and was able to get one ;) And it was not the plastic gear that was worn but rather the flat part which got a groove from the rubber seal.

15514109636_b9bba2a895.jpg

Edited by nino

Correct!

That said even cases from 2007 would fit! The only thing that changed is the bolt diameter. From 1999 -2007 they have upped the diameter by about 1mm when compared to 1990-1998. They went from 8 to 9mm engine bolt diameter.

Nino I've seen your bikes they all look awesome, some day I hope to have a few 125's that special. But if what you are saying is correct I can buy an old say 93 engine off ebay throw it my 98 frame and go riding with no modification, I mean other the spacing and positioning the boot or something minuscule? And have a back up motor?

Nino I've seen your bikes they all look awesome, some day I hope to have a few 125's that special. But if what you are saying is correct I can buy an old say 93 engine off ebay throw it my 98 frame and go riding with no modification, I mean other the spacing and positioning the boot or something minuscule? And have a back up motor?

Correct!

Engines from 90-97 are basically identical. The only thing that changed was some porting and ignition timing etc...minor things really.

 

As mentioned elsewhere 90/91 had round pistons and obviously different heads to go along

92-99 all have flat pistons so you can swap cylinders and heads as you want from 92-97 and 98/99 (remember the slightly wider transfer ports on those two years, but that can be made to fit)

98/99 have slightly wider transfer ports at the cases but nothing that you can't get to match with minor work.

'99 is still the same but has slightly wider diameter at the motor mount bolts. You could still enlarge the holes on your chassis though....or still use the slimmer bolts.No issues.

90-97 are 6s while 98/99 are 5s. But transmissions can be swapped out. A complete 6s tranny will fit 98/99 cases and viceversa.

Tip: on ALL HPP engines the valves&guides off the 98/99 models work best.

 

ALL other parts are basically the same. No mods needed. You can install a '90 engine in your '98 without any issues.

 

By the way - that's what i have as well: i was able to buy a complete '99 with a blown engine for 400$. I rebuilt that engine with new crank,bearings and everything so i have a new '99 engines as a "spare". I now have 4 engines for my three 125s and they range from 93-99 and all fit into the other frames as well.

 

3 of my 4 engines....93, 98 and 99 all outfitted with '90/'91/'90 Mugen kits....basically all engines identical

 

9464853177_b7b8d6b263_z.jpg

 

....and fit in all 3 of my bikes: '90 with VRP aluminium chassis, '98 and '12 AF

13483689804_a4f6603be7_z.jpg

Edited by nino

Correct!

Engines from 90-97 are basically identical. The only thing that changed was some porting and ignition timing etc...minor things really.

As mentioned elsewhere 90/91 had round pistons and obviously different heads to go along

92-99 all have flat pistons so you can swap cylinders and heads as you want from 92-97 and 98/99 (remember the slightly wider transfer ports on those two years, but that can be made to fit)

98/99 have slightly wider transfer ports at the cases but nothing that you can't get to match with minor work.

'99 is still the same but has slightly wider diameter at the motor mount bolts. You could still enlarge the holes on your chassis though....or still use the slimmer bolts.No issues.

90-97 are 6s while 98/99 are 5s. But transmissions can be swapped out. A complete 6s tranny will fit 98/99 cases and viceversa.

Tip: on ALL HPP engines the valves&guides off the 98/99 models work best.

ALL other parts are basically the same. No mods needed. You can install a '90 engine in your '98 without any issues.

By the way - that's what i have as well: i was able to buy a complete '99 with a blown engine for 400$. I rebuilt that engine with new crank,bearings and everything so i have a new '99 engines as a "spare". I now have 4 engines for my three 125s and they range from 93-99 and all fit into the other frames as well.

3 of my 4 engines....93, 98 and 99 all outfitted with '90/'91/'90 Mugen kits....basically all engines identical

9464853177_b7b8d6b263_z.jpg

....and fit in all 3 of my bikes: '90 with VRP aluminium chassis, '98 and '12 AF

13483689804_a4f6603be7_z.jpg

So does this mean that a 97 transmission will fit in to the newer cases I know you can do it with the 98/99 cases, but never heard of anyone doing it with anything newer.

Also what about stator/ stator plate and the cdi's can you take a 93 stator and run it with a 99 cdi, or do you have to run to whole 93 system or vise versa with the whole 99 system.

Sorry for all the questions but this is new and exciting info for me haha.

Edited by funke5372

Hey I know this is old but I have a 97 cr125 and I'd like to know if the cdi unit on it is the same as the one on the 96, thanks.

So i'm late too haha. i have a Honda cr 125 (2002). my left crankcase is cracked. too cracked 2 fix. so the question is can a 97 crankcase fit on my 02 motor? looks the same and has the same numbers (54.5mm) or do i need to buy a new one? and if so can you send me a link where i can find a perfect match? thanks! :)

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