Cange front sprocket?

Have a look here HO, might help.

 

Hi HO, first of all let me say that my comments are based on the work I did on my 2010 T100 which had an 18t std front sprocket.

1. When I changed from an 18 to a 19T front sprocket it dropped the revs at 60mph by approx 300 - so not that much.

2. Changes in how the bike rode - I needed more clutch when taking off, particularly if two-up; but once running it felt good - but I should say that I had modified the engine to give more torque,so maybe that's why it coped with the higher gearing quite easily.

3. With your bike - 5000rpm at 70mph sounds to me like someone had changed the front sprocket for a 17t as that is revving quite high for the speed, imo.

4. As you can buy front sprockets for about £12-15 apiece, why don't you buy both and experiment between all three? I used to change mine often, depending on what I was planning to do with the bike over the following week.

5. I believe that if your bike has a std.length chain, the tensioners will cope with fitting an 18t or a 19t front sprocket.

My advice? Buy a couple of sprockets from here and do some experimenting.

http://shop.tecbikeparts.com/products/19-tooth-gearbox-sprocket

 

Good advice from biglad as ever. I had an 04 Bonnie with the 18 tooth sprocket and changed quite happily to the 19 tooth one from tecbikeparts. I remember a drop of about 300rpm at 60mph being about right - 5000rpm at 70mph sounds like a 17 tooth one as that's a wee bit high.
It will feel more relaxed on longer runs and leaves you less likely looking for that non existent 6th gear.

 

Yo, I'm with t'others, my SE Bonnie had 19T, toured Belgium no probs

 

Hi HO,you might find this interesting,there are some good tips here for doing the job.

 

You can H.O., you can.

 

No you can do it that way.

 

You can do the job by:
1. slackening the front sprocket nut

2. slackening the rear axle, moving the adjusters all the way forward,

3. there will now be enough slack so that you can then lift the chain off the front sprocket;

4. Replace the current sprocket with the new one and refit the the retaining nut using a small amount of locktite and a new tab washer;

5. Re-set chain tension.

It's good to have a couple of new tab washers in stock, part number

21. PFKL1182311 NUT. GEARBOX SPROCKET £ 4.25(€ 4.85)
22. PFKL1198524 WASHER.SPROCKET £ 6.30(€ 7.18)
23. PFKL1198671 SPROCKET. G/BOX. 17T £ 20.28(€ 23.12)

 

Hi Terry you are certainly getting there, well done