hahaha, I just came to the realization that I now have a box containing 4 different pistons out of 4 different motors that I have trashed so far.... Thats sad.
- Justin
- Justin
YamaSaki YFSex-250 build
- Thread starter justin.naekel
- Start date
Yeah they work now.
Ouch, that looks bad, but I think you can just clean it up with a toothbrush and car cleaner, lol
Ouch, that looks bad, but I think you can just clean it up with a toothbrush and car cleaner, lol
A little simple green and some duct tape should do the trick. Will report back with the results.
There is an old saying for times like this. DPO. Dreaded Previous Owner. I learned it well working on old bikes.
So the new top end is back together. Only thing left is to adjust the valves (gotta pick up a new feeler gauge) and then install the cam chain tensioner and recheck timing and torques and then new oil and were good to go I think.
Tha was a f*cking marathon though. Split case, cleaned everything, put bottom end back together, clean up new top end, install top end using combination of old motor parts and new motor parts. Take top end all apart again after glancing down and seeing my shiney new base and head gaskets still sitting on the bench. Install gaskets and reassemble again. Oh and let's not forget searching for my tourque wrench that was still packed from the move.
Thank god for pirated repair manuals though.
Will report back more tomorrow. Im f*cking exhausted.
- Justin
Tha was a f*cking marathon though. Split case, cleaned everything, put bottom end back together, clean up new top end, install top end using combination of old motor parts and new motor parts. Take top end all apart again after glancing down and seeing my shiney new base and head gaskets still sitting on the bench. Install gaskets and reassemble again. Oh and let's not forget searching for my tourque wrench that was still packed from the move.
Thank god for pirated repair manuals though.
Will report back more tomorrow. Im f*cking exhausted.
- Justin
Its...... its...... its alive! ITS ALIVE! BUAHAHAHAHAHA
[/MadScientist]
It runs. And seems to run good. Now I need to get the rest of the bike back together, get it tuned and jetted right and we are back in business.
- justin
[/MadScientist]
It runs. And seems to run good. Now I need to get the rest of the bike back together, get it tuned and jetted right and we are back in business.
- justin
sounds good brother... Now get some vids or at least more pics up before the pic whores come out to play lol.
so more (long overdue) updates...
Finally got the whole thing back together and running and tuned up and all I can say is HOLY SH*T!!! it is amazing what a Ninja 250 motor can do when properly jetted and tuned and all of the top-end parts are in the motor.
It still needs to be geared, but the test ride today was very sucessful. I was paced by my GF in my truck at 67mph - and I still had 2 more gears to go. Whats more is that in 1st it had no problem with any obstical i threw at it. Granted, I have not tried it in the sand yet, but on the trails this thing is just plain stupid (in a VERY VERY good way).
I will get some more pics up shortly and video hopefully if I can figure out how to get it off of my GFs phone. the kinda cool thing about this is that first is so tall that it basically covers me for everything - 2nd and up are just bonus gears!
Heading to MOAB on thursday and will report back after a few rides there and hopefully (if starbucks in moab has wifi) I will get some video up as well. I have 2 GoPros and 4 SD Cards ready to go for this one.
I'm going to work on the carbs a bit more and see if I cant squeeze a bit more out of it. I know right now my biggest restriction is the exhaust but not much I can do about that right now. It seems to like to peg out the rev limiter pretty quick and the backpressure helps with the low-end so I may not mess too much with it but I might be able to get a bit more from it. Man does it sound mean as hell with those dual pipes!
- Justin.
Finally got the whole thing back together and running and tuned up and all I can say is HOLY SH*T!!! it is amazing what a Ninja 250 motor can do when properly jetted and tuned and all of the top-end parts are in the motor.
It still needs to be geared, but the test ride today was very sucessful. I was paced by my GF in my truck at 67mph - and I still had 2 more gears to go. Whats more is that in 1st it had no problem with any obstical i threw at it. Granted, I have not tried it in the sand yet, but on the trails this thing is just plain stupid (in a VERY VERY good way).
I will get some more pics up shortly and video hopefully if I can figure out how to get it off of my GFs phone. the kinda cool thing about this is that first is so tall that it basically covers me for everything - 2nd and up are just bonus gears!
Heading to MOAB on thursday and will report back after a few rides there and hopefully (if starbucks in moab has wifi) I will get some video up as well. I have 2 GoPros and 4 SD Cards ready to go for this one.
I'm going to work on the carbs a bit more and see if I cant squeeze a bit more out of it. I know right now my biggest restriction is the exhaust but not much I can do about that right now. It seems to like to peg out the rev limiter pretty quick and the backpressure helps with the low-end so I may not mess too much with it but I might be able to get a bit more from it. Man does it sound mean as hell with those dual pipes!
- Justin.
I had my KTM/Blaster sprocketed up to over 70mph for a bit.
Doesn't this seem a bit too fast on a short wheelbase with 4psi tires?
I know, I know... There is no such thing as too fast!
Doesn't this seem a bit too fast on a short wheelbase with 4psi tires?
I know, I know... There is no such thing as too fast!
and as promised... some video from moab.
This is the first. I have 4 days of video to edit so there is more to come. I will do another with no music in just a bit.
more video and info coming on performance.
- Justin
This is the first. I have 4 days of video to edit so there is more to come. I will do another with no music in just a bit.
more video and info coming on performance.
- Justin
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dude, it looks like it does REALLY well on trails.
Glad to see you found the weak link on 4 different ninja 250 engines but found a combo that works!
Glad to see you found the weak link on 4 different ninja 250 engines
but found a combo that works!dude, it looks like it does REALLY well on trails.
Glad to see you found the weak link on 4 different ninja 250 engines
HAHAHAHA... yeah...
Anyway - uploading a new vid right now.
It did great on trails. Climbing over rocks not so much, but on the other hand it was not designed for that kind of thing... some of the trails I was doing 50mph+ (working on finding those clips) in 4th gear pinned and having a blast.
I was having an issue with the motor loading up on me pretty bad just this side of half way through the rev range once everything was all warmed up and im not sure if that is a carb issue or a gearing issue as the gearing is still pretty bad.
- Justin
a little bit of trail followed by a high-speed run back to camp.
- Justin
- Justin
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So all in all, here is my summary of the swap (even though i havent worked out all the kinks yet):
Everything is on a scale of 1 - 10, 1 being not so good, 10 being really good
Overall Info and Ratings
Ease of swap: 3 (was easy enough for me but there are much easier swaps to do)
Fit & Finish: 6 (some minor issues but my design tailored to the oversized engine)
reliability: 8 (sans the first motor - the EX250 motor is famous for its reliability)
Overall user friendliness: 6.5
Now on to the good stuff. The motor has a redline of 14,500 RPM so the following are approximations of RPM and performance.
Power and performance (RPM Range)
Idle - 3000: 2
3000 - 6000: 3
6000 - 9000: 6
9000 - 12,000: 8
12,000 - RL: 8
Terrain and Conditions (Overall performance)
Smooth Pavement: 8.5
Smooth dirt/gravel road: 9
Smooth dirt trail: 8
rocky trail, some ups and downs: 7
mixed terrain rocky/smooth: 7
technical terrain (trees, boulders, obstacles): 5
hill-climb (mild): 5.5
hill-climb (steep): is there anything below 1?
All this said, if i had a choice, would I do this one again? as it sits now - no. BUT, the carbs still are not fully set and the gearing needs to be changed.
Is it a bad swap to do? Absolutely not. I think it is a great swap so far, but it just did not stand up to my expectations (granted I had unrealistically high hopes). If you want to do smooth terrain and maybe some flat track or ice racing, this setup would be great. I tend to ride more technical terrain so its not perfect for me, but i will reserve full judgement until i have the gearing handled and the carbs fully tuned, then I will re-evaluate the situation so I will leave this a running thread.
In terms of is this motor better than the stock motor? Yes and No. It makes noticeably more power and is significantly faster, however it has a HUGE weight disadvantage and is seriously lacking in bottom end grunt due to the streetbike gearing in the transmission.
for what its worth, I actually am glad I did this from the stand point that I feel it is a better motor choice than stock for this from a performance standpoint, but for the same money I could have gone with something in the single cyl flavor out of a dirtbike that makes more power and less weight.
- Justin
Everything is on a scale of 1 - 10, 1 being not so good, 10 being really good
Overall Info and Ratings
Ease of swap: 3 (was easy enough for me but there are much easier swaps to do)
Fit & Finish: 6 (some minor issues but my design tailored to the oversized engine)
reliability: 8 (sans the first motor - the EX250 motor is famous for its reliability)
Overall user friendliness: 6.5
Now on to the good stuff. The motor has a redline of 14,500 RPM so the following are approximations of RPM and performance.
Power and performance (RPM Range)
Idle - 3000: 2
3000 - 6000: 3
6000 - 9000: 6
9000 - 12,000: 8
12,000 - RL: 8
Terrain and Conditions (Overall performance)
Smooth Pavement: 8.5
Smooth dirt/gravel road: 9
Smooth dirt trail: 8
rocky trail, some ups and downs: 7
mixed terrain rocky/smooth: 7
technical terrain (trees, boulders, obstacles): 5
hill-climb (mild): 5.5
hill-climb (steep): is there anything below 1?
All this said, if i had a choice, would I do this one again? as it sits now - no. BUT, the carbs still are not fully set and the gearing needs to be changed.
Is it a bad swap to do? Absolutely not. I think it is a great swap so far, but it just did not stand up to my expectations (granted I had unrealistically high hopes). If you want to do smooth terrain and maybe some flat track or ice racing, this setup would be great. I tend to ride more technical terrain so its not perfect for me, but i will reserve full judgement until i have the gearing handled and the carbs fully tuned, then I will re-evaluate the situation so I will leave this a running thread.
In terms of is this motor better than the stock motor? Yes and No. It makes noticeably more power and is significantly faster, however it has a HUGE weight disadvantage and is seriously lacking in bottom end grunt due to the streetbike gearing in the transmission.
for what its worth, I actually am glad I did this from the stand point that I feel it is a better motor choice than stock for this from a performance standpoint, but for the same money I could have gone with something in the single cyl flavor out of a dirtbike that makes more power and less weight.
- Justin
JMO, but if you did 67 with two gears to go and the fact it seemed you were slipping the clutch on real rough stuff, cosider gearing down a bit. Love your riding area tho, kick @$$. I:I I:I
JMO, but if you did 67 with two gears to go and the fact it seemed you were slipping the clutch on real rough stuff, cosider gearing down a bit. Love your riding area tho, kick @$$. I:I I:I
Yeah the gearing is currently 14/40 or 2.8:1 andam looking to get it tohe 3.2-3.4:1 which should be 13/44-46... having a hard time finding a 13t front tho... haven't looked that haryet tho.
- j
** UPDATED **
And now the latest...
I finally got around to ordering gearing. I decided that I would go with the 13/46 combination as that a) gives me better low-end and b) I dont loose much ground clearance on the rear sprocket and c) I could still use my original chain and didnt have to buy a new one. So thats what I did.
What showed up, however was different. I got the front sprocket ok, and the rear sprocket, which was marked as a 46, was actually a 49. F*CK! now I gotta get a new chain because I can be bothered with sending it back and I though, we let me see what this will do.
So off to the local MC shop for a chain. $43 later I have everything I need for the gearing swap.
Got everything all bolted up and was ready to test, only to find out that the big sprocket would not clear the chain guide bracket. Off that went.
Now with every thing all up and adjusted I just have one thing to say. WOW!
this thing is a BEAST now. first gear has plenty of tourque and still runs out long enough to make it usefull. Second gear feels better than first gear did with stock gearing. I would place first gear (with stock gearing) right in between 2nd and 3rd with the new gearing.
Granted I have not tried this out on the trail yet, but that will happen later today.
That said, below is my revised evaluation thus far. Adjustments will be made as the testing progresses.
Everything is on a scale of 1 - 10, 1 being not so good, 10 being really good
Overall Info and Ratings
Ease of swap: 3 (was easy enough for me but there are much easier swaps to do)
Fit & Finish: 6 (some minor issues but my design tailored to the oversized engine)
reliability: 8 (sans the first motor - the EX250 motor is famous for its reliability)
Overall user friendliness: 7.5 (previously 6.5)
Now on to the good stuff. The motor has a redline of 14,500 RPM so the following are approximations of RPM and performance.
Power and performance (RPM Range)
Idle - 3000: 4.5 (previously 2)
3000 - 6000: 4.5 (previously 3)
6000 - 9000: 7.5 (previously 6)
9000 - 12,000: 9 (previously 8)
12,000 - RL: 9 (previously 8)
Terrain and Conditions (Overall performance)
Smooth Pavement: 9.5 (previously 8.5)
Smooth dirt/gravel road: 10 (previously 9)
Smooth dirt trail: 9.5 (previously 8)
rocky trail, some ups and downs: 8.5 (previously 7)
mixed terrain rocky/smooth: 8.5 (previously 7)
technical terrain (trees, boulders, obstacles): 8 (previously 5)
hill-climb (mild): 9 (previously 5.5)
hill-climb (steep): 7.5 (previously SUCK)
Sand on knobbies: 6 (No Traction - lots of wheel spin and no bogging)
Sand with paddles: Unknown - Didnt get to the paddles
Overall, now that I have it for the most part set up, I think this is an EXCELLENT choice for a motor swap. I realize, although not 2-stroke, it is still a kick in the pants to ride. With the gearing on it now, there is NO problem at all negotiating technical or steep obsticals and there is ample amount of thrust. It is not break-neck quick, but I didnt want that. I wanted a nice controlable amount of power that is sufficient to ride basically whatever I throw at it without being more than the chassis can handle and I think I have found that.
The only real problem I have now is the chain slack when the rear end is compressed. I am working on a spring loded tensioner to help this as with the larger rear sprocket, i have a little bit of slapping on the lower part of the front sprocket cover and if im REALLY hard on it (sitting back and dumping the clutch to wheelie) it will hop the sprocket (NOT GOOD) so I am working on building the tensioned roller for that (yes I realize I could just one but wheres the fun in that?)
- Justin
And now the latest...
I finally got around to ordering gearing. I decided that I would go with the 13/46 combination as that a) gives me better low-end and b) I dont loose much ground clearance on the rear sprocket and c) I could still use my original chain and didnt have to buy a new one. So thats what I did.
What showed up, however was different. I got the front sprocket ok, and the rear sprocket, which was marked as a 46, was actually a 49. F*CK! now I gotta get a new chain because I can be bothered with sending it back and I though, we let me see what this will do.
So off to the local MC shop for a chain. $43 later I have everything I need for the gearing swap.
Got everything all bolted up and was ready to test, only to find out that the big sprocket would not clear the chain guide bracket. Off that went.
Now with every thing all up and adjusted I just have one thing to say. WOW!
this thing is a BEAST now. first gear has plenty of tourque and still runs out long enough to make it usefull. Second gear feels better than first gear did with stock gearing. I would place first gear (with stock gearing) right in between 2nd and 3rd with the new gearing.
Granted I have not tried this out on the trail yet, but that will happen later today.
That said, below is my revised evaluation thus far. Adjustments will be made as the testing progresses.
Everything is on a scale of 1 - 10, 1 being not so good, 10 being really good
Overall Info and Ratings
Ease of swap: 3 (was easy enough for me but there are much easier swaps to do)
Fit & Finish: 6 (some minor issues but my design tailored to the oversized engine)
reliability: 8 (sans the first motor - the EX250 motor is famous for its reliability)
Overall user friendliness: 7.5 (previously 6.5)
Now on to the good stuff. The motor has a redline of 14,500 RPM so the following are approximations of RPM and performance.
Power and performance (RPM Range)
Idle - 3000: 4.5 (previously 2)
3000 - 6000: 4.5 (previously 3)
6000 - 9000: 7.5 (previously 6)
9000 - 12,000: 9 (previously 8)
12,000 - RL: 9 (previously 8)
Terrain and Conditions (Overall performance)
Smooth Pavement: 9.5 (previously 8.5)
Smooth dirt/gravel road: 10 (previously 9)
Smooth dirt trail: 9.5 (previously 8)
rocky trail, some ups and downs: 8.5 (previously 7)
mixed terrain rocky/smooth: 8.5 (previously 7)
technical terrain (trees, boulders, obstacles): 8 (previously 5)
hill-climb (mild): 9 (previously 5.5)
hill-climb (steep): 7.5 (previously SUCK)
Sand on knobbies: 6 (No Traction - lots of wheel spin and no bogging)
Sand with paddles: Unknown - Didnt get to the paddles
Overall, now that I have it for the most part set up, I think this is an EXCELLENT choice for a motor swap. I realize, although not 2-stroke, it is still a kick in the pants to ride. With the gearing on it now, there is NO problem at all negotiating technical or steep obsticals and there is ample amount of thrust. It is not break-neck quick, but I didnt want that. I wanted a nice controlable amount of power that is sufficient to ride basically whatever I throw at it without being more than the chassis can handle and I think I have found that.
The only real problem I have now is the chain slack when the rear end is compressed. I am working on a spring loded tensioner to help this as with the larger rear sprocket, i have a little bit of slapping on the lower part of the front sprocket cover and if im REALLY hard on it (sitting back and dumping the clutch to wheelie) it will hop the sprocket (NOT GOOD) so I am working on building the tensioned roller for that (yes I realize I could just one but wheres the fun in that?)
- Justin
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Just Realized i had the wrong video here.... Here is the high-speed run...
- Justin
Last edited by a moderator:
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