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

Members Login
Post Info TOPIC: James' 350 build


Member

Status: Offline
Posts: 9
Date:
James' 350 build
Permalink  
 


Hello,

I am a new member, and about to start a 350 build, I have a 2004 Blue bike and am new to everything to do with motorbikes, apart from falling off!

I have got my shiny new 350 kit from Steve and have bought a pair of crank cases to work with. I have removed all the bearings and seals from the cases and they are away being machined. I am picking them up on Tuesday. I have bought new bearing and seals from a mixture of Steve, Bearings are us and Simply Bearings.

So to start off with I have a couple of questions for those who know more than me. First, two of the bearings I removed from the crank case are sealed, but on one side only, the open side being the side inside the crank case. The replacements are sealed on both sides. Should I remove the plastic seal on one side of the bearing (presumably to allow the oil from the crank case to get into the bearing) ?

Second, having read the other threads about 350 conversions, it seems that there is some talk about painting the outside of the bore, what type of paint would people use for this and would you use something different for the rest of the engine, in which case what?  

I will try and post some pictures of things as the build progresses, and will no doubt have many more questions.



__________________


Super Guru

Status: Offline
Posts: 1248
Date:
Permalink  
 

Wow! In at the deep end or what?!

Welcome to the forum James.

Yes, just pick one seal out with a pointy thing.

Technically, a heat resistant paint should be used for the barrel, but it's not too important. I use a heat resistant satin black, but a silver would be a closer match to the cases. You could leave it bare, but I think that leaves it open to furring up corrosion from salty roads. If you like the self-coloured look though, there are heat resistant clear engine lacquers available. Take your pick...

Good luck!

Simon.

__________________


Member

Status: Offline
Posts: 9
Date:
Permalink  
 

Hello again,

I have now managed to get the bottom end of the engine back together and am just about to put the new bore and piston back on, I notice from reading other 350 threads that the upper two rings are marked for their upper side, but could someone tell me if I should assume that the gaps are correct, or do I need to measure them.

Thanks for any advice.



__________________


Super Guru

Status: Offline
Posts: 1248
Date:
Permalink  
 

So far I have not come across any rings that were incorrect. Marks uppermost, correct.
Make sure you space the gaps evenly, not all in a row down the piston.

__________________


Member

Status: Offline
Posts: 9
Date:
Permalink  
 

Thanks for that, I have now fully re assembled the engine, and amazingly it runs!!

I could do with a bit of advice on jet sizes though as it seems that people are getting good results with a variety of different jets. I have 147 main, 48 pilot and my needle was on the second ring from the bottom. I have moved the needle up one ring, on the basis that it seems the new engine needs a richer mixture.

Any advice on whether to change it more or to leave it as is would be very welcome, also other that checking the spark plug colour, does anyone have a good method of checking if it's right or wrong.

Thanks in advance to anyone who can offer help



__________________


Member

Status: Offline
Posts: 9
Date:
Permalink  
 

Forgot to say I have a shorty header pipe and one of Steve's Phoenox exhausts, if that makes any difference.



__________________


Super Guru

Status: Offline
Posts: 1248
Date:
Permalink  
 

Well done!
The 350 runs richer than the 250 with stock airways, but as you have freer flowing pipes the carb should not be too far out.
Run it it carefully (see link in the 350 thread) and enjoy!

__________________


Super Guru

Status: Offline
Posts: 2510
Date:
Permalink  
 

Glad it's up and running, Whats up with the bike then, popping like running lean and hits flat spot?



__________________

totallyttrs.com

 



Member

Status: Offline
Posts: 9
Date:
Permalink  
 

Thanks for the replies, my impression is that the engine although running is running very rich, plug is covered in black soot when removed, so I think I will bring the needle up a notch back to where it was and see if that improves things.

Unfortunately I think I have another much more significant problem in that the gear change doesn't seem to be working properly. I can select 1st and neutral . but I cant get any other gears at all. When I was assembling the engine, I tried the gear selection in both directions after I had joined the crank cases together, and they seemed to work fine, but now no luck. Has  anyone got any ideas as to what might be going on before I take the entire engine to pieces again. - Very frustrating!

Also I was wondering if this thread might be better moved to a different area, but if so would have no idea how to do it.

Any help or ideas welcome



__________________


Super Guru

Status: Offline
Posts: 8376
Date:
Permalink  
 

Hopefully the gear change issue is something simple James! 

What has changed since you checked the gears?

I guess that you are turning the engine over whilst trying to change the gears.

Sounds like you may need, as a first step, to remove the clutch cover and check what is happening at the selector.

The symptoms you describe are the same as when the gearchange spring retaining post has broken.

See the attached photo and check yours looks the same. Also, with the cover off you can try changing gear and see exactly what's happening. 

Brian

Steves clutch side complete without casinga.JPG



__________________

Exeter, Devon, UK

http://www.ttr250.com  - The one and only dedicated TTR250 FAQ! 
 

TIP: For easy viewing bookmark the "Recent Posts" view - http://ttr250.activeboard.com/p/recent/ 



Member

Status: Offline
Posts: 9
Date:
Permalink  
 

Hello again, thanks for you help Brian, I seem to have solved the gear change problem, but I'm not quite sure how! I fiddled around a bit with the position of the selector arm on it's spindle and now it changes ok thank goodness.

I now have a slightly different worry, which is the carb jetting. As I mentioned earlier, I am running a 147 main jet with a 48 pilot and I had the needle in the middle grove. I am running a shorty header and one of Steve's Phoenix tail pipes. The engine is running ok, but it crackles a lot on releasing the throttle and when not moving, the header pipe is starting to glow red where it leaves the head. - I would have thought that was an indication that it was running lean. At that time I had a home made side panel on the air box with lots of holes in it and no snorkel. After a conversation with Steve, in which he pointed out that this would contribute to it running lean, I put the side panel and the snorkel from my other bike on and left the carb settings as they were. - No change at all, didn't even alter the idle speed! still crackling on letting the throttle go and exhaust beginning to glow. So now I have moved the needle to its lowest slot and tried again, with the air box as it should be. This seems to have helped, the crackling much less (almost gone) and the exhaust does not seem to get so hot.

Anyone got any ideas here, because it seems that the thing should be running very rich with that set up especially when I compere the settings with what others have said they are using.

Could it be something really basic like deposits in the jets effectively making them smaller in which case can I simply open them up again and if so how best to do it? or is there so much individual variation within the different engines that this is within normal limits.

I notice some of you are talking about using an air fuel gauge to see if you are running rich or lean, it this a sophisticated expensive bit of kit, or are the ones on ebay for about £30 any good 

Sorry to have so many questions, but any help would be much appreciated.



__________________


Member

Status: Offline
Posts: 9
Date:
Permalink  
 

Just had a bit more of a look at air/fuel ratio gauges, it seems you need to have a hole in your header pipe for the sensor, anyone know if its possible to get something that does it at the tail pipe?

__________________


Veteran Member

Status: Offline
Posts: 60
Date:
Permalink  
 

Well, with that setup, you need a bigger pilot jet, 50 or 52 even better and find the sweet spot for the screw. No need to buy a gauge, many owners here have the same setup and measured AFR.

__________________


Super Guru

Status: Offline
Posts: 2510
Date:
Permalink  
 

Agree Christos.

James after talking on the phone, I remember altering my needle clip and it made the bike run rough, went up on the pilot jet 54 ( though that seems crazy large) and all was good, can't remember what my main jet was though, maybe 147, whats yours?



-- Edited by ttr steve on Wednesday 29th of June 2022 08:38:04 PM

__________________

totallyttrs.com

 

Page 1 of 1  sorted by
 
Quick Reply

Please log in to post quick replies.



Create your own FREE Forum
Report Abuse
Powered by ActiveBoard