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

SussexTony · Senior Member

Hard starter

ttboof · Super Guru

As you have a voltmeter once it's running does the voltage rise to around 14v

If so it's charging

If the battery is at 12.7 it's prob charged.

If the voltage drops when you crank it's likely the battery has no cranking capacity (dud)

If the motor doesn't crank and the voltage only drops slightly it could be solenoid or brushes (low current draw)

SussexTony · Senior Member

Thanks for reply but I’ve bypassed the solenoid? Put wires to back of starter, I will check starter under load , but the starter is new and when I put old starter on bike same problem! Could it be big end bearing!

SussexTony · Senior Member

It’s definitely worse when cold, but when engine is hot seems to turn easyer! And the battery is new , and I’ve even tr a car battery witch reads 12:9 v ! I think there might have been a problem with this before because the last owner left the shims off small idle gears I think to try and make things abit loseer! but now bikes had new piston and rings ,it’s made things tighter ! is there any way of me finding out?

-- Edited by SussexTony on Tuesday 24th of November 2020 08:18:38 AM

-- Edited by SussexTony on Tuesday 24th of November 2020 08:35:28 AM

ttboof · Super Guru

Just like to rule out the odd things

Is the earth wire nice and tight

Are the terminals crimped to the leads OK (the ends would heat up if they are) both positive and negative

SussexTony · Senior Member

Thanks again for your reply, all wires tight, I’ve spoke to vortex racing, who used to have work on my bikes back in the day, and he didn’t think it would be big end bearing because the bike runs fine on bump start , he said double check everything from starter to sprag, if I still have no joy take everything I’ve got old , starter, old sprag, old idle gears, , and engine, does not need the bike just engine, and he will sort it out , the more i spoke to him he seems to remember me, and laughed and said what was I doing on a ttr 250 but I said I bought it to teach my boy how to ride, and he got it! I was thinking now my boy nos how to ride it would be nice to give him more power. So looks like 350 kit ! Does not look like any in stock, but have seen something in USA , so we will see , thanks again

TTRfan · Super Guru

Hi Tony

If you take the spark plug out and try turning the engine over on the flywheel bolt, does it turn easily? It should do. If not, it may help to identify the problem area.

Brian

SussexTony · Senior Member

Hello mate I took the engine out today , and thought I would have a last look at it before I take it to the shop, and it definitely getting lock up! Flywheel, small idle gear spin freely, starter good spins freely, but as soon as u fit the idle gear on. Starter it’s binding, feels like it hitting side caseing I bought a pair of idle gears together from eBay, the thinking there was so they would mesh together, are all side caseing the same?

-- Edited by SussexTony on Tuesday 24th of November 2020 06:38:14 PM

ttboof · Super Guru

I haven't had any experience with the side covers.

I'm sure you will get an answer soon

I have read some crack. The binding seems odd though.

The engine might be an easy check just by getting a socket on the end of the crank and feeling how it turns

My bike has the wisco oversized piston and new battery can be a bit reluctant to turn over on hot rides over 35/40odd Deg days when stalled . It's a 2010 blue with a kick start as well but don't use it

TTRfan · Super Guru

Could the idler gears be mismatched? See here

SussexTony · Senior Member

Thanks for your reply’s ! Well all I can think of is to try and count the amount of theeth on idles , and go from there? Well a quick change of subject , I went to bikes of Brighton, ( motorcycle shop) and I had to wait for the shop to open , so I parked just down the road. I was laying back listening to elvis on cd quite loud , next minute I had a tap on the window it was the man from the motorcycle shop he was pointing at 5 or 6 people dancing and singing,it happened I had parked outside of a post office they must of been in there 70’80s all dancing so funny so it didn’t matter what was wrong with the bike today, thanks to elvis I’ve had a big smile on my face all day!

ttboof · Super Guru

Thanks for the story smiling here as well

SussexTony · Senior Member

Just had phone call from vorex racing, he seems to think that where the last owner had left out the shims off of the small idle gear it then progressed to make movement on the larger idle gear ( by starter) even though the small bearings had not fallen apart in my hands and they fitted on the pinion they are f,,, ! And that is why it then naffed the starter up , so that’s sorted , well let’s hope so? So on the tear down of the engine,he noticed that the timing was out that much he was shocked the bike still run ! Unless chain had jumped, so then I started talking about the 350 kit , he said the crankshaft and bearing all look good the piston still looks good , I think he said the design of small end bearing probably not the best, witch I didn’t understand what he meant by that ? And then he said he’s going to do something with the cams? He said about the 350 kit , if it was him he would leave it and if I love the bike that much I should probably get a second engine and rebuild that , so that’s what’s happening well at least my boys will have his engine back by next weekend and he. Seems to think it’s going to cost between £ 150 , 250 depending on cams so not that bad!

TTRfan · Super Guru

Thanks for the update Tony! So, are the starter gears 1 and 2 properly matched?

PS There TTR doesn't have a little-end bearing as such. The gudgeon pin runs directly in the conrod. I have only ever seen a problem where the owner had run the bike out of oil - and I have seen the innards of dozens of TTR engines over the years wink

SussexTony · Senior Member

Thanks for that, that’s good to no, well all I no is that I had two different sets of idle gears I can’t remember what my old ones were but I No that new ones were 16/14 and 19/72 , but the old ones definitely different, hopefully when I get the engine back next week I will no more ! I no that marcanic said he agreed with everything that Steve u and everyone said that Chinese stuff is crap ! And he’s only had a couple of things that were any good over the years, he stays away from it unless he can’t get hold of something and it’s still pop luck? He said that he’s got to service his husky next week and he will let me have ago around the track! Can’t wait!

SussexTony · Senior Member

Brian cant you move to East Sussex , lol I would love to move to west county but I’ve got a building company, maybe one day when my boy older enough to run it , I’m half retired now , just noticed that you’re all tier 1 , well at least u can go for ride ! I’ve

-- Edited by SussexTony on Thursday 26th of November 2020 06:54:13 PM

TTRfan · Super Guru

Lucky folk in Cornwall are Tier 1. Us Devonians are in Tier 2 sadly so grandsons still won't be able to come for their weekly tea with us cry

Devon's problem is caused by our cities (Exeter, Plymouth and Torbay) who are letting the side down very badly meaning the rest of us in the rural areas (with hardly any cases) have to suffer restrictions unnecessarily cry