EXHAUST / GEARING

Paul P · Post by **Paul P** » 07 Apr 2003, 13:10

Will a cr 250 powerpipe fit on a mk3 crm 250 and if so would it be an improvement ? does anyone know what sort of top speed 14 / 48 would give and does anyone else out there own a mk 3 crm 250 with purple mudgaurds and yellew side panels

Russell · Post by **Russell** » 07 Apr 2003, 15:04

My Mk3 has a Purple tank but thank God the mudgaurds are yellow.

Luke Davey · Post by **Luke Davey** » 11 May 2003, 08:01

yes, my mudguards are purple, and the side panels are yellow, why do you ask

Russell · Post by **Russell** » 11 May 2003, 16:15

My MK 3 is flat out at about 75 with 13 50 gearing

double_clutch · Post by **double_clutch** » 11 May 2003, 23:37

75mph flat out! surely it must be restricted? my old dt125 did 70mph! im sure my crm is quicker than 75, although ive never had it flat out since my nasty accident on it

Post by **admin** » 12 May 2003, 06:45

thats not restricted, just russell has it geared very low. bet it lifts the front in third with no effort and first gear is near useless

Phil Neal · Post by **Phil Neal** » 12 May 2003, 08:36

What would be a good gearing for green laning, I think the standard may be a bit high, whats the biggest you can go on the back without changing the chain? or is it ok just to shove another sprung link in? (I never seem to go over 60-70 on the road due to traffic etc.)

Never sure at what point to go for a rivited chain, I'd heard anything over 125cc and you are risking it abit?

Russell · Post by **Russell** » 12 May 2003, 09:37

I run 13 50 gearing with 114 link chain, I replaced all sprockets and chain at same time so did not have to extened chain I simply took it to the shop and they selected the best chain. The biggest rear sprocket I have run was 53 this was great for lifting the front wheel but you had to change gear more often than a restricted moped. My bike is never used on road except to ride to garage to fill up and spends most of its life in an old chalk pit lots of hills and tight turns, I never get out of third if higher gearing so 13 50 is good for my needs but may not suit people who use on road. Mine will lift in third and on a good day you can keep front wheel in the air through first four gears.
The only change to bike for bigger sprockets is to fit a dropper plate to chain guide.

double_clutch · Post by **double_clutch** » 12 May 2003, 20:50

if you have a bigger rear sprocket the big does more wheelies but has a slower top end (more low down speed than top end speed) and if you have smaller sprocket on back it will keep the front end down and make it faster top end (less low doen speed and greater top end)?????????

help im confused

larger rear sprocket = .............................................?
smaller rear sprocket = ..............................................?

jackstribe · Post by **jackstribe** » 12 May 2003, 21:51

DC here's the explanation.

just like a mountain bike, a bigger cog at the back makes the wheel easier to turn, hence lots of wheelies. cos the wheel spins quickly more easily, then it cannot get any faster as engine gets faster, hence low top end.
the opposite is true of a smaller rear sprocket.
with a rear sprocket, the number of teeth can be quite varied eg 40 to 53 teeth difference on the CRM.

a smaller cog at the front is also same as an mtb, so to put a smaller cog on the front is OPPOSITE to the rear, ie it will make the wheel turn quicker, hence wheelies etc. a larger front sprocket makes the top end longer but accelerate slower. the difference in teeth is not very much eg on a CRM you would have either 12, 13, 14 or maybe 15 teeth at a push.

hope everyone understands this ramble!!!!!!!

SteveOldGit · Post by **SteveOldGit** » 13 May 2003, 20:22

Its nearly new C&S time for me as my chain is virtually shagged!

Is the conclusion that 13/50 (as suggested by Russell) is the best gearing for 80/90 % off road? (fairly hilly stuff)

+ any recommendations for a supplier? is it our friends at L.T.? Also, Russell, sorry to show my ignorance! but what is a 'dropper plate for chain guide'? and were do i get it from? if i go for this gearing?.

Thanks for any replys.

Post by **admin** » 13 May 2003, 20:48

The dropper, is the chain pre tensioner (located in front of the rear sprocket). If you go above 47 on the rear this catches the sprocket and isnt low enough. The modded one LT sell will allow much larger sprockets to be fitted.
Hope this helps

SteveOldGit · Post by **SteveOldGit** » 15 May 2003, 20:38

DOH!

(apologies for being a mechanical thicko!)

Thanks Admin for your advise.
Looks like there be more 'beer vouchers' heading L.T's way in the near future

Steve.

Paul P · Post by **Paul P** » 29 May 2003, 09:31

refering to the top of the page and Luke Davey I only ask because ive owned my bike for almost 1 year and I have only ever found one picture on the internet and when I go to a bike store they just scratch there heads

EXHAUST / GEARING

EXHAUST / GEARING

same colours

Recommended Gearing?

purple and yellow