TTR325 Review/Report

Did you use the stock TTR wheel, axle and brake parts or are YZ parts needed? My guess would be that the YZ axle is a must have for this conversion.



I used the complete front end of a yz, front wheel, axel, brake disc.

I am using the ttr caliper on a custom bracket, but I see no reason why you can't just use a yz front brake. I couldn't use the ttr speedo drive as although the yz front wheel i got has the housing for it, it was smaller than the ttr one. (my guess is the front wheel is actually off a WR?)

So all I need to do now to get it through its MOT next year (MOT is a yearly test to make sure the bike/car etc is road legal her in the UK) is to put on a cats eye speedo.

Thanks again MrFlaky! That's what I needed to know. I figured the best (read: easiest) solution would be to use all the YZ parts. Makes sense. I am starting to aquire all the parts for my winter conversion now. All my bike needs to be streetlegal is a speedometer/odometer. The Trail Tech Vapor is the one I have decided on. I don't need the stock tripmeter anymore. All that goes!


Hey all sorry been away for a while, I have been in the hospital and am just now getting good again. a little report on the bike after a year, the motor is great and works like a dream I am thinking of playing with the gearing a little but it will have to wait for spring, I am going to put the studded tires on as soon as the doc says it is ok to ride. Now for the front end, it has been revalved with gold valves and set up for my style, I road two enduros on it and find it pushes in the corners I am going to lower the forks in the clamps and see if it helps. if not I am going to go with bar risers and lower them a little more, I think I just need to get a little more of the weight to shift to the front end. the race sag is set and other then a little push it is great, I could use a new front tire also but I think I just need to get the balance worked out for the cornering thing.

Oh yea on the 325 kit I would suggest getting the kick starter kit that comes with a hand compression release, it seem to work the starter motor a little and I had to put a new one on, but the old one was 7 years old so it was a little tired, the kick starter kit you can get from yamaha. I am going to get one this winter.

what did you hate so much about the wr?

Nice conversion, very similar to the KDX/KX front end swap that I did last winter. The only difference being that the KDX stem must be pressed out and pressed back into the KX lower clamp. I used the extra stem nut as a spacer and had to shim around the stem a little as it was a bit small for the upper KX upper clamp.

what did you hate so much about the wr?

If I recall correctly, Bryan's main beef with the WR was that it was peaky and it didn't lug as well as the TT-R (I agree). The 450s are the best of both worlds :thumbsup:

Still though, riding technical terrain (albiet a little bit slower) nearly pinned on a small mellow trail bike makes you feel like a hero. Riding the same terrain on a faster more high strung bike barely on the throttle and slipping the clutch to keep from stalling makes you feel like a squid :busted: I've been on both sides of that scenario and fully understand some rider's appeal for mellower trail bikes like XR's, TT-Rs, and DR-Zs

So Bryan hows the 325 going now?

Hows it holding up reliability wise?

My current ride is An Australian model 1997 TT350, I'm considering buying a 2000 TTR250 that is due for a piston and putting the 325 kit in, but i want the bike to be ultra reliable and not have overheating issues etc.

Also how much die the kit cost in total (adding cost for machining and rejetting at the end)


I am curious as well... How's the bike holding up? Any other mods you'd consider?


It is holding up great, I have about 500 miles on it.






On a side note I just order the kick started kit for the TTR 250 , it ships today I will give a report when it is in, I mostly order it for the compression relese, the big bore kit seems to work the starter and it kick out sometimes and it has shredded the teeth so I order another starter and it is doing the same thing, I think if I have the compression relese and use it when I first hit the starter buttom it will get things moving with less effort and save the starter, that and I want the kick starter for the time you are in the deep woods and the batt might go just as a back up.

Ya I know more weight but hey it is a TTR 325 not a wr and is the weight really an issue for a guy like me, I think not :eek:

I have the kick starter and one kick normally does the trick. I had the comp release installed then took it out as I didn't need it. It also took up valuable space on my bars that I didn't have to waste.

Have you changed gearing due to the increase in power?

Hey bryan i am considering getting this kit for my ttr. Has the extra power stuffed your gear box or did you have to get stronger gears made up for it? any other comments would be really helpfull.


hey bryan, i got a ttr250 2007, i think is the same than lower years. i got exhaust and jetting mods. but i thinking about get the 325 kit. do you need to get the whole engine or only the cilinder case to get it bore.

also i install an oil cooler i think it will work better with the 325 kit doesn´t it.


I had a look at this kit in a UK website, and they said they would not deal with anyone in australia, like myself, so do you know of anyone over this way, doing the kit?

was it all that hard to put the YZ front end in it? is there any bad bits about the change? I have an 07 i wouldn't mind doin this to, as the YZ front end would be lighter too.

yes , I would like to do so as well. I t will be nice. but we will have to change the complete front end including brakes.

Two of us in the UK have just taken delivery of ThumperRacing's 325cc kit and are looking forward to getting our engines done and in our bikes.

Sadly there are no specifications included for anything with the kit and I need to know the tolerance for the piston/barrel when I take it to be bored. Does anyone know please?

Also, anyone else in the UK fitted the kit?


Amazing bike- what sort of headlight is on it? doesn't look like OEM, how does it go compared to the factory? I will be attempting to duplicate your mods on my TTR250.

Two of us in the UK have just taken delivery of ThumperRacing's 325cc kit and are looking forward to getting our engines done and in our bikes.

Sadly there are no specifications included for anything with the kit and I need to know the tolerance for the piston/barrel when I take it to be bored. Does anyone know please?

Also, anyone else in the UK fitted the kit?


It has taken a long time but at last we got the machining done and the engines running. First impressions are good. The extra grunt is very noticeable. Sadly there was a problem with the machine work (done locally in the UK) and the barrels are back in the machine shop for remedial work.

What we noticed on removing the barres is that there are some hairline cracks running horizontally between some of the fins that are allowing oil to seep out. Not in great quantity but enough to make the barrels mucky. This has happened on the forward facing (exhaust) and the LHS and rear of both the barrels. Anyone else experienced this and know a possible remedy please?


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