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| Air Cleaner For CR Cylinder Swap? https://vintagedirtbikeforums.alp-sys.com/viewtopic.php?f=21&t=3054 |
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| Author: | ~JM~ [ Sun Jul 10, 2011 6:39 pm ] |
| Post subject: | Air Cleaner For CR Cylinder Swap? |
A question for those of you who have swapped a CR top end onto their MT250. What did you do for an air cleaner? I have one set up that worked OK for the MT cylinder, but it isn't going to work now for the CR top end. Thanks ~JM~ |
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| Author: | woosh [ Mon Jul 11, 2011 4:24 pm ] |
| Post subject: | Re: Air Cleaner For CR Cylinder Swap? |
I just put a uni filter on the carb and called it good. It has no airbox to speak of just a carb out in the wind. |
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| Author: | woosh [ Mon Jul 11, 2011 4:24 pm ] |
| Post subject: | Re: Air Cleaner For CR Cylinder Swap? |
I just put a uni filter on the carb and called it good. It has no airbox to speak of just a carb out in the wind. |
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| Author: | JonW [ Tue Jul 26, 2011 7:35 pm ] |
| Post subject: | Re: Air Cleaner For CR Cylinder Swap? |
My worry with just a uni filter is that if you hit any water your engine is going to suck it right in, I am about to fit the CR250 top end on my MT and was hoping i might make the original filter box work with a filter from ReMx, is that a goer or will it be too restricted? Ive not seen any photos of how big the 73/74 CR airbox was originally compared to the MT so its hard to know. |
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| Author: | ~JM~ [ Wed Jul 27, 2011 11:28 am ] |
| Post subject: | Re: Air Cleaner For CR Cylinder Swap? |
The CR box will not fit the MT frame from what I've been told. The CR cylinder/head is taller than the MT & places the carb up higher. The carb outlet & the frame are very close to each other, limiting your choices for an air-boot, air-box, etc. |
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| Author: | JonW [ Wed Jul 27, 2011 3:18 pm ] |
| Post subject: | Re: Air Cleaner For CR Cylinder Swap? |
Ahh, now i see. Cheers for that. back to the drawing board! LOL |
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| Author: | rayivers [ Wed Jul 27, 2011 4:58 pm ] |
| Post subject: | Re: Air Cleaner For CR Cylinder Swap? |
I wonder if the MR250 unit will fit? The 34mm MR250 carb has a 62mm mouth, 43mm spigot, and is 98mm long. http://cgi.ebay.com/ebaymotors/1976-HON ... 8301157598 Ray |
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| Author: | JonW [ Wed Jul 27, 2011 5:28 pm ] |
| Post subject: | Re: Air Cleaner For CR Cylinder Swap? |
Looks quite different, but i expect you could make it fit... anything will fit given time and a few deft hammer blows. In think part of the problem for the MT is that the battery sits under the airbox so that leaves a smaller box that sits high in the frame, the lid is on the top as the sides are too small. What I may end up doing is fabricating a box to fit the frame if i go that route, but its a pain as it stands. Perhaps if i ditch the battery... i guess the turn signals will still run when the engine is running, id just need a one of those battery eliminator resistors to stop the charging circuit from buring itself out, hmm... then maybe the MR box might fit... tho isnt the MR based on the 76 CR frame, whereas the MT is the 73/74 CR base? the plot thickens... |
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| Author: | rayivers [ Wed Jul 27, 2011 7:13 pm ] |
| Post subject: | Re: Air Cleaner For CR Cylinder Swap? |
Jon, If possible, it might be worth a try keeping the MT airbox and trying to mate it to the bigger carb (Vintage Iron may have a smaller-I.D. accordion-looking 250 air boot like they have for the 125). The early CR250M and MR250 air boots are also worth looking at. I used an MT250 air filter for two years on my MR175 until I got one of the UNI filters from the eBay guy in New Zealand (dabbernz). The MT filter worked fine, it was certainly plenty big enough for a modified 175 motor. I removed the airbox lid and ground off the top lid ridge, which created an opening around about 70% of the filter's top circumference and let a lot more air into the box and sides of the filter (before that, the top would get dirty way before the rest of the filter). Ray |
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| Author: | ~JM~ [ Wed Jul 27, 2011 10:10 pm ] |
| Post subject: | Re: Air Cleaner For CR Cylinder Swap? |
JonW wrote: ...id just need a one of those battery eliminator resistors to stop the charging circuit from buring itself out, hmm... I tried one of the battery eliminator capacitors on my MT & it kept blowing out the taillights. I ended up using a small AGM 6V battery that sits in my original tool tray. ~JM~ |
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| Author: | JonW [ Thu Jul 28, 2011 1:37 am ] |
| Post subject: | Re: Air Cleaner For CR Cylinder Swap? |
Ahh yes JM, i remember your thread on that, good call. |
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