A forum for owners of Yamaha TTR250 trail and enduro bikes!

It is surprising what performance you get if you use the revs and keep the motor spinning 

I did the Rally of Discovery North Devon a few years ago and managed to keep up with my mates on a WR450F (Hampster) and a CCM 650 (Big Jim). I needed to do a lot of gear shifting to keep it in the power band and be a bit brave on the corners. I only lost them on the longer straight road sections. They were quite surprised at how well the TTR went. I certainly decoked the engine that weekend 

Air filter needs to be clean, spark plug properly gapped (maybe an Iridium would help?), plus Super Unleaded petrol but most importantly valve clearances set correctly and the engine to have good compression. If the piston is worn and the valves need grinding in then you will lose performance.

You are welcome to have a go on my spare unmofified 250 if you want to compare it with yours? Same engine etc.

Brian

We are running the iridium plug, a short primary pipe, FMQ muffler, 140 main, 52 pilot, needle up one notch, no snorkel and 14/46 sprockets. Performance is excellent both on and off road.

Hi shack

The bikes (two of them) were new in 2010. The stock jetting as supplied (Aussie model) was 140 main and 50 pilot. We changed to 52 pilots without first testing based on what we read on some forums - flat spot, lean on part throttle etc. However have since realised we probably did not need to as we ride in over 30deg ambient temps and 50 pilots would probably have been ok. The needles were also raised one notch at this time, one was put back to original some time later with no noticeable difference.

The exhausts were replaced after the carbs were altered so we didn't actually rejet to suit the exhausts. The FMQ website said no rejetting required, but with the current carb setups they go like rockets.

The biggest initial improvement came from removing the exhaust restrictor in the original primary pipe, this allowed the engine to rev through it's entire range. The next big improvement came from totally removing the airbox snorkel and fitting the short primary pipe. However I wouldn't recommend removing that snorkel if you are going anywhere near deep water. Some owners cut it back - we tried that and it helped, but removing it really opened the airflow up.

Doubt that the iridium plug makes a huge difference - we fitted them because they last much longer than the standard plug and changing the plug is not an enjoyable job.

I guess they best way to judge the performance of your TTR is to ride a "known good" one as Brian suggests.

shack wrote:

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I will have a look at my exhaust (oem at present) as removing that restictive collar seems an easy mod 

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 I think you may be disappointed Shack. I have only ever seen the restrictor fitted to blue TTRs but I would be happy to be proved wrong 

Brian

shack wrote:

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Hi all, had my first big blast on new bike, and just wondering how my old raid compares to other TTR's out there, now I took it over Exmoor and up Porlock Hill (steep and a little cheeky if your not familiar with it) and made it up and down without issue.

I have to work the box a lot more than any other bike I've had recently (say 15 years or so) and often downshift to keep progress at a sprightly 50mph, I've got dual purpose tyres and road pressures at the moment so road manners aren't bad, tis just slow off the mark with a top whack of about 65 (and happy to stay at 50 all day)

I've not counted the teeth on the sprockets but from the history I know of the bike, I'd guess they are what Yam suggest (a garage replaced C and S as part of MoT)

I have changed air filter and reduced the snorkel al la pictures in mod section and TBM mag.

Do I need to just to get used to the 250, or does what I say sound very diferent to your performance? and what can I check?

 

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