CRM AR 250 Engine Rebuild Costs

[Mudfacetony]

I've looked very hard to find what Maico conrod they might use and haven't found anything yet of the same dimensions as a CRM (I've tried a lot of other bike manufactures as well). As far as I know the original source of the LT conrod being Maico was 'Johnny's tool box' (or something similar). However I have found that there are some untruths in the story told on his website and he has never returned any emails I have sent. Thus I am not sure of the 'Maico' provenance .

Has anyone had LT say to them that the conrod is Maico .

Also I have never heard LT talk about Maico pistons . Before it has always been TRX pistons. Is this something new in that the conrod and piston give the same stroke and piston height dimensions as a CRM

Tom who works on the parts counter told me it is a maico rod but did not expand on it. i understand it is a trx piston because of the little end. i thought about contacting one of the ebay sellers of maico rods with the sizes of the crm to see if they can come up with anything

[fallenmikethebike]

I've looked very hard to find what Maico conrod they might use and haven't found anything yet of the same dimensions as a CRM (I've tried a lot of other bike manufactures as well). As far as I know the original source of the LT conrod being Maico was 'Johnny's tool box' (or something similar). However I have found that there are some untruths in the story told on his website and he has never returned any emails I have sent. Thus I am not sure of the 'Maico' provenance .

Has anyone had LT say to them that the conrod is Maico .

Also I have never heard LT talk about Maico pistons . Before it has always been TRX pistons. Is this something new in that the conrod and piston give the same stroke and piston height dimensions as a CRM

Tom who works on the parts counter told me it is a maico rod but did not expand on it. i understand it is a trx piston because of the little end. i thought about contacting one of the ebay sellers of maico rods with the sizes of the crm to see if they can come up with anything

That's worth pursuing as a line of enquiry, at some point every one will need a replacement.
Mike

[helisupp]

Trouble is if you use this non standard conrod the AR must have the barrel re machined larger and replated, expensive solution to not having an original conrod available.

[Active Rascal]

The con-rod also doesn't have the holes to allow fuel to lubricate the small end bearings so well!! :(

[knackeredMk1]

With respect to Helisupp's post above - If you use the 'Maico' conrod then you must use the TRX piston as the little end on the new conrod is 1mm smaller than the original CRM one. TRX pistons are sized 66.0, 66.25, 66.5, 66.75 .................. NOT 66.4 (CRM250AR)

[knackeredMk1]

I've done some further research.

As far as I can measure the CRM250 is - 132.5mm between centres, 23.0mm little end, 32.0 x 16.5mm big end. Can someone confirm these measurements

I can't find any Maico rod that fits. There only seem to be two rods that they use :

250 - 131.7 between centres, 22 little end, 31 wide by 17 thick big end
400, 420, 440, 490 - 137, 22, 31 x 17

I have found a Rotax BT20 rod that is closer -

132, 22, 31 x 17.

Only the between centre length cannot be easily overcome. I understand that the LT conrod has a 22mm little end.

[Active Rascal]

I have my old CRM conrod... And possibly could get someone to accurately measure it at work. More difficult jow as Ive moved jobs. I didnt measure the new one but there's pics of it in my project write up. I'm almost certain LT said it was from Italy but they wouldn't say what bike it was for.

[knackeredMk1]

I'm going to stop looking into this. I've spent a lot of time on it and though I don't like being beholden to someone about the source of parts - at least we do have a source. I very much doubt that if we do find the source we will be able to buy conrods cheaper anyway. So I'm settling on the stats quo unless someone says the centre to centre measurement is 132mm.